Transcript for:
Human and Social Biology Crash Course

c-sec human and social biology paper two broad topics speed run let's go cellular organization so first of all the cell is the basic unit of life in each cell are organelles such as the nucleus and the mitochondrion each of these perform specific rules in the cell now these cells can be specialized or differentiated for destructors to perform specific functions so for example sperm cells have flagella or like little tails that allow them to swim towards eggs to fertilize them now many similar cells comprise tissues and many similar tissues combine to form organs in this case here we could have muscle cells that form cardiac muscle tissue which is found in the heart and the heart is part of a bigger organ system that is called a circulatory system so organs together with many tissues from organ systems and an organism so the order here is going to be organelle cell tissue organ organ system organism in terms of increasing complexity here we have an animal cell animal cells have a more globular irregular shape in the animal cell the organelles include the nucleus which contains genetic material that includes dna and rna and it regulates cell activity then we have the mitochondrion and this is a site of atp production or respiration the gel-like substance that fills up the cell and helps keep its shape as the cytoplasm and this is also the site of chemical reactions surrounding the cell is the cell membrane or the plasma membrane and this facilitates entry and exit of some molecules based on their charge and based on their size basically only small molecules can enter and exit thus it is called partially permeable within the animal cell they are small temporary vacuoles which act as water and mineral storages there's a an endoplasmic reticulum or an er and these help to package proteins and these are usually lined with ribosomes that help synthesize or make proteins here we have an undifferentiated plant cell this has a more regular elongated shape it contains many similar organelles as the animal cell which includes the nucleus mitochondria the cytoplasm the cell membrane the ribosomes and the endoplasmic reticulum and vacuoles except now the vacuole in the plant cell is large and permanent this is because the plant cannot actually get up and move around it has to store much more water and minerals than animal cell does they are true organelles that are not found in animal cells and only found in plant cells in this case here this would be the chloroplast which is the site of photosynthesis or glucose production using light the outermost layer which is called the cellulose cell wall this supports and maintains the internal water pressure in the cell and it prevents itself from bursting or undergoing lysis i would turn their starch grains which are energy reserves let's compare both types of cells the nucleus is found in both animals and plants mitochondria boat cytoplasm boat cell membrane both types of cells the chloroplast is not found in an animal cell but only in plant cells same thing release a low cell wall not in our animal cell but is in a plant cell the endoplasmic reticulum many ribosomes are found in boot the energy storage in an animal cell is due to glycogen granules being a plant cell it is starch greens and vacuoles are found in boat but in animal cells it is small and temporary in plant cells they are large and permanent specialized or differentiated cells have specific tasks in multicellular organisms and thus they have fetias and adaptations to assist in performing those tasks so below we have a few examples red blood cells transport oxygen and carbon dioxide that is the function of the red blood cells now to help with that they have a disc shape or biconcave shape similar to a donut without a hole and this easily allows oxygen to diffuse into the red blood cell it also helps to keep the oxygen within it has hemoglobin to bind the oxygen and no organelles so that it has a high oxygen carrying capacity the sperm cell helps to fertilize the egg it has a tail or flagellum that allows it to swim it has chemicals in the head of the sperm that help it to penetrate the egg the neuron transports electrical messages through the body on the cell body it has branches or dendrites that connect to other neurons they are also chemicals that are secreted called neurotransmitters that help to regulate transmission epithelial cells line the surfaces of organs such as the small intestine and the alveoli they are very thin to allow diffusion of materials and you may have hairs or cilia to increase surface area muscle cells tend to have a high amount of mitochondria to facilitate a high rate of respiration and energy release they have to do a lot of work so they can contract and they can relax egg cells are large much larger than sperm cells and can contain receptors on your cell membranes that interact with the binding of spoon cells connective tissue cells contain structural proteins like collagen and are found in tendons bones and fatty tissue viruses are not cells they are clean non-living and non-cellular they are pathogens that cause infection all viruses are harmful they contain a protein coat that houses dna and rna and these provide instructions to the ribosomes and cells to make more copies of viruses to infect more cells they are spikes on the outer envelope that act as keys that allow them to enter the cells bacteria are much larger than viruses and some bacteria can be beneficial to humans such as the ones in yogurt they do not have a nucleus instead they have loose dna in a nucleoid region and they have circular dna called plasmids they have cell walls for support similar to plants but it's not made up of cellulose and some of them have flagellar tails that allow them to be motile or be able to move fungus cells are similar to plant cells except they don't have chloroplasts they have cell walls made up of chitin or cellulose and they reproduce by budding which is breaking off a section of a cell which would then develop into a new cell examples of fungi would be bread mold and yeast photosynthesis is a process where producers take in inorganic molecules and using energy from sunlight produce organic substances such as glucose photosynthesis occurs in chloroplasts which contain green pigment chlorophyll the main inorganic molecules or reactants are carbon dioxide which enter tree leaves and water which enter through the roots grammar glucose is the main product and oxygen is released as a byproduct here's a formula for photosynthesis you only have to concern yourself with the word formula carbon dioxide plus water gives you glucose plus oxygen here we have a setup to observe the effect of light on photosynthesis so when undergoing photosynthesis a plant would release oxygen so if you use an underwater plant such as elodea this would release oxygen bubbles in the water and i said you'd see it as rising bubbles gathering at the top of an inverted test tube so you see a column of air here and this will begin bigger and bigger as the flat as the plant photosynthesizes so as you increase the intensity of this light bulb here the rate of oxygen bubbles will also increase so you'll be seeing more and more bubbles coming out at a faster rate this is because photosynthesis is occurring at a faster rate if he was to make this light bulb brighter however past a certain light intensity you could say that the chlorophyll becomes saturated with light particles and the rate of evolution of oxygen will be the same throughout that means that if you make the bulb brighter past a certain point you're not going to get a foot increase in bubbles so oxygen is released from the leaves during photosynthesis as just said and you can actually observe this by using a glue and splint is similar to a long match and what this would do is that it would react with the oxygen and it would allow a smaller flame to combust and burn more brightly so if he was to light this and put it in oxygen upon a leaf that is released in oxygen you will see that it would combust into a bigger flame this proves that oxygen is released during photosynthesis testing for presence of starch and leaves while excess glucose is converted to starch which is stored in leaves roots shoots stems and fruits presence of starch indicates that photosynthesis has occurred or is occurring so how do you test for starch well first of all you have to place the leaf in a water bath to break down the cell walls this is basically um heated water then you place the leaf in ethanol to remove the chlorophyll mermaid leaf with all the chlorophyll would not look as green it would look like a very pale green oil kind of whitish next using a dropper you add a few drops of iodine solution and wherever there is a blue black color that is going to indicate the presence of starch you can easily test this using a variegated leaf which is a leaf that contains chlorophyll in some parts and no chlorophyll in other parts of course the green areas have chlorophyll and these are the areas that are going to contain starch these are the areas that are going to photosynthesize so when the starch test is carried out the previously green areas are going to turn blue black because those there contain starch the iodine is going to react with the parts that contain chlorophyll and the parts that didn't contain chlorophyll the iodine is not going to react with that so those are not going to experience a color change here we have the carbon cycle and first to understand the carbon cycle let's start with carbon dioxide in the atmosphere there's really only two ways in which carbon dioxide is removed from the atmosphere the main way is through photosynthesis where carbon dioxide is absorbed into the leaves of plants and then transfixed into carbohydrates such as glucose and starch the other way which is not shown in this diagram is when carbon dioxide is absorbed by the ocean or water sources so let's start with photosynthesis so plants undergo this process and they remove carbon dioxide from the atmosphere so it keeps it from building up next animals are going to feed on the plants so consumption is going to happen when the animals eat the plants they're going to get those carbohydrates and that carbon in their bodies animals now will respire and when they respire basically when they breathe out the animals are gonna exhale co2 and that's gonna return to the atmosphere when the animals and the plants die they are gonna decompose and the decomposers are gonna break down the organic dead matter and that is also going to release carbon dioxide into the atmosphere but whatever remains in the soil over a long period of time that is going to fossilize so fossilization occurs when the decomposed material become fossil fuels after many years basically when they get compressed and over a long period of time with some heat these turn into oils or fossil fuels now those fossil fuels are pumped up and are then burnt to power things like automobiles and factories and even the electricity that we have here all of that there is run by oil and gas so when fossil fuels are burnt that releases carbon dioxide into the atmosphere the main problem is when we burn too many fossil fuels and this atmospheric carbon dioxide level starts to increase drastically and especially if we start to cut down trees there'll be less and less ability to remove that carbon dioxide from the atmosphere so deforestation means that fewer trees lead to a decrease in the rate of photosynthesis there's less leaves to take up that carbon dioxide so the carbon dioxide from the atmosphere is not diffusing to the leaves and the levels remain very high now if we burn a lot of fossil fuels all the time this will raise carbon levels due to the emission of gaseous carbon compounds into the atmosphere lastly if we have a lot of sewage runoff that excess carbon dioxide from the sewage would cause oceans to become acidified so the overall impact on humans from the carbon cycle is while climate change more heat energy from the sun is trapped in the atmosphere this would increase temperatures and more adverse weather patterns for example hurricanes sea level rise occurs when the polar ice caps melt due to this rise in temperature and coral bleaching has just said when excess carbon dioxide causes oceans to become acidified this would destroy any coral reefs and any aquatic life that lives within the coral reef so how do we reduce our human impact on carbon cycle well first there's re-afforestation this basically means replanting trees that have been cut down this will reverse any habitat loss for animals and allow photosynthesis to at greater rates to remove their carbon dioxide from the atmosphere we can use alternate forms of energy so for example wind turbines solar panels hydroelectric dams and biofuels from crop harvests all of these here reduce the combustion of fossil fuels and dust release of carbon dioxide into the atmosphere we can just reduce our fossil fuel usage so basically encouraging carpooling public transport using more energy efficient fluorescent lights hybrid vehicles more energy efficient appliances and then we have carbon taxes which the normal citizen cannot employ but governments can and these provide incentives to companies and countries to limit carbon dioxide emissions basically they will produce a fine for some companies if they go over a certain limit you could also produce fines for open combustion of materials so unlike residents burn rubbish that also releases carbon dioxide into the atmosphere the nervous system consists of the central nervous system or cns and this includes the brain and the spinal cord and the peripheral nervous system or the pns and this includes the spinal and cranial nerves so electrical impulses or action potentials are very rapid messengers of sensory input from receptor cells and carrying instructions to effectors such as muscles or glands so neurons are cells which make up these pathways and nerves are bundles of these neurons so basically throughout these cells here we are going to get electrical signals being sent from sensory organs such as the skin for example to the brain to the spinal cord and eventually to muscle so that we can react to those signals so there are three types of neurons sensory neurons motor neurons and interneurons or relay neurons let's look at motor neurons so motor neurons on the end here we have a cell body and this contains organelles such as nuclei and mitochondria branching out from these cell bodies are dendrons and smaller dendrites these conduct impulses received from other neurons you could think of them as connecting points the axon is a long process that goes along the cell and this is where the impulses are conducted so the impulses will be conducted through the dendrites through the cell body and down the axon like this think of the axon as a cord that is attached to the cell body neurons are involved in the life process called irritability which is the ability to detect and react to stimuli so here we have sensory neurons so sentry neurons are found only sense organs such as the skin or the retina and they detect stimuli and pass them on to the central nervous system to be interpreted as stimulus is any detectable change that occurs in the environment so for example a change in temperature remember motor neurons are connected to effectors and these effectors are like muscles or glands and these could facilitate movement or responses to the stimuli so for example let's say that you touch a hot flame the the burn on your hand the increase in temperatures is stimulus but you moving your han away is response sensory neurons are similar in structure to motor neurons as you could see here but the cell body is not on the n inside the cell body is located in the middle of the axon now between two neurons there's a gap that gap is called as synapse and synapses are sites that lie between two successive neurons so there's a gap between the two neurons called the synaptic cleft and they are chemicals secreted from the neuron through these little sacs called vesicles and these chemicals are called neurotransmitters these neurotransmitters are is acetylcholine these allow the propagation of electrical impulses across the synapses basically what that means is that think of the neurotransmitter building a bridge between the two neurons so it could cross this little gap here so when the impulse comes through this neuron the neurotransmitter could allow it to to go to this other neuron here so nicotine from cigarettes also acts as a neurotransmitter but it causes synapsis fire too often synapses help to regulate transmission of electrical impulses so that he moves down fire too often so when there's a problem with the production of neurotransmitter this is where that area might go numb if there's an overproduction of it that's where the person might have like parkinson's where they'll be moving involuntarily here we have the human brain the human brain consists of the main region which is called the cerebrum the hindbrain which is called the cerebellum the brain stem or the medulla oblongata we have the hypothalamus which is like a regulatory center and we have the pituitary gland which is the master gland for the release of hormones so the cerebrum deals with memory emotion judgment and senses example sight and hearing without this we won't be able to do any of those things the cerebellum is used for movement and coordination the medulla oblongata or the brain brainstem is used for the autonomic nervous system these are the things that you don't really think about so this includes breathing heart rate reflexes involuntary movements the hypothalamus is used for deregulation of body temperature and the pituitary gland regulates the release of certain hormones so i said before stimulus is a detectable change in the environment that the body can react to in this case here the food is similar so the descent of the food and the response from the dog is going to be to produce saliva so other examples would be an increase in temperature increase in light intensity a painful hit on the body and the response is the body's reaction or change as a result of detecting the stimulus so for example an increase in temperature would cause sweating a decrease in temperature would cause shivering an increase in light intensity would help the people constrict a painful hit you'd probably move away from the danger so an involuntary response is called a reflex now reflexes can be conditioned if there's repeated exposure to the stimuli and repeated responses over time so for example if you're training a dog with a whistle or with food or you have a little clicker which is training a cat to approach you voluntary actions are deliberate actions that involve total input from your brain so basically the signal travels from the brain through the spinal cord and then to motor neurons that connect the muscles so if you have to lift this glass of water to drink it you'd have to think about it send that signal to your muscles and that would lift your hand for you to drink the water that's a deliberate action so motor neurons connect to effectors such as muscles which will act on the electrical signal to enact responses involuntary actions are reflex acts so these are rapid actions that are automatic and they do not involve input or analysis from your brain so there is no sensory input from your brain in this case so if you have a spinal reflex so for example let's say someone touches this flame by mistake and they have to pull away their hand the electrical signal or electrical impulse is going to travel from the receptors in the finger to the sensory neurons in the hand and then to relay neurons or interneurons in the spinal cord then to motor neurons that will connect to effectors any muscle remedy factors are what help with the response in this case here it's gonna help to withdraw the hand from the flame or the hot stove or if it's with the knee it's gonna provide a knee-jerk reflex so there are cranial reflexes as well that do not really involve the spinal cord and in this case are the messages sent to the motor neurons and cranial muscles so this is basically when you have a reflex that involves the face so for example blinking if there's something approaching you or the pupil reflex where spinal reflexes more deal with moving your body here we have an internal view of the eye feel free to pause the video and know the labels because there's a lot to unpack here first let's look at the cornea the cornea is the front part of the eye it is a very thin layer and this helps to refract the light so that it can actually enter the eye the light enters the eye through a small hole called the pupil and the iris adjusts the size of the pupil based on the light intensity we'll get more into that later so the light enters through the pupil and the lens focuses that light on a retina the retina contains receptor cells called rods and cones these help to form an image the fovea is the highest concentration of those receptor cells so when the image is formed on the retina this is at the back of the eye the image is actually inverted and now it must be sent to the brain to be analyzed and processed so how that image is sent to the brain is that it is converted into electrical signals and sent via the optic nerve the optic nerve is going to connect to the cerebrum and the brain is going to reinvert or reorient the image so that we see it right side up if any light rays fall on this pointy on the optic nerve no image is going to be formed here this is called your blind spot so other parts of the eye that help with focusing involve the suspensory ligaments and the ciliary muscles these are connected to the lens so if the let's say for example if you have to look at something very close these ciliary muscles are gonna contract and the suspensory ligaments are gonna loosen a little bit and what's gonna happen is that this lens is gonna change size we'll get more into that just now this lens is gonna change size and it's gonna be thicker and that's gonna help to focus on closer objects and further objects the opposite is gonna happen so the part that protects the eye is called sclera this is the white part of the eye and this is what will we will prevent it from mechanical damage and so on the actual fluid within the eye that helps the regulator's pressure is called vitreous humor on the front of the eye it is called aqueous humor and the choroid prevents any internal reflection of light within the eye so let's go through this again the cornea refracts the light as it enters the pupil the iris is gonna adjust the size of the pupil in bright and dark environments the lens is gonna change shape to focus the light on the sensory cells at the back of the eye this is where the retina and the phobia are the image forms on the retina and that's going to be inverted and is going to be sent to the brain via the optic nerve as electrical impulses a debris in the image is then going to be processed and analyzed and reoriented accommodation is the process where the lens becomes thicker or thinner to focus light on the lens so when you're looking at a near object if you look here the object as is getting closer the lens is going to thicken this is because the ciliary muscles are going to contract and the suspensory ligaments are going to loosen and if you look at a distant object so you see here when this object is more is further away the lens is flatter this is because the ciliary muscles relax and the suspensory ligaments tighten [Music] so once again you can see here if the person is looking at a distant object their lens would flatten this is because the ciliary muscles relax and so as you can see here once again if you're looking at a distant object the lens would flatten the ciliary muscles would relax and the suspensory ligaments are going to tighten if you are looking at a close object imagine that you're looking this if you put your finger close their eye and they try to focus and focus on it you'll notice that there's a strain in your eye this is because the lens is thickening due to the contraction of the ciliary muscles these suspensory ligaments are gonna loosen to allow this to happen now in both these cases here you'll notice that the light rays converge exactly on the retina this is to form a sharp image if the light rays do not converge on your retina you're going to get a blurry image so this is what happens when a person is short-sighted or long-sighted so in this case here you'll see that the image is not formed in a retina where they are formed either before the retina or after in this case here we're gonna get blurry images so short-sightedness or short-sighted vision or near-sightedness um is caused by the lens being too thick or the eyeball being too long the image is gonna form before the retina it means that the light is going to be like focus a little too much so in this case here the image is formed within the vitreous human not only retina the sharpest image this is also called myopia and it needs concave lenses to mend it long-sighted vision of far-sighted vision or hypometropia occurs when the lens is too weak or is too thin the eyeball is too short and in this case here the image forms behind the retina and not only retina itself you need convex lenses in order to mend this other eye conditions include astigmatism which occurred due to the deformation of the cornea so without special lenses or laser corrective surgery the images are blurred glaucoma occurs due to the build up of capillary pressure intraocular pressure near the optic nerve this is within the vitreous hume of the eye this would cause blurry vision and pain and prescription eye drops on oral medication may help to alleviate this cataracts are clotting of the lens in the eye basically you could see it as little white spots within the eye that basically block the pupil on the lens these can be surgically removed diabetes can lead to damage of the optic nerve and this leads to blurry vision and eventual blindness hormones are secretions of endocrine glands that are directly released into the bloodstream and act as chemical messengers they act on target cells that have receptors specific to that hormone they are typically slow acting but have prolonged or long-term metabolic effects so these are usually released let's say for the regulation of blood sugar or during puberty or deregulation of water in the blood so these endocrine glands secrete their substances directly into the bloodstream they do not have any ducts or they are called so called ductless glands these include the pituitary gland in the brain the thyroid gland in the neck the adrenal glands that are right above the kidneys the pancreas in women there's the ovaries and in men there's the testes so some examples of hormones include adh or anti-diuretic hormone these help to conserve water in the kidneys and in the bloodstream so that it can be reused for sweating don't urinate out oily water adrenaline is used to increase heart rate and breathing rate and scenarios of stress like when you're writing the hsb exam growth hormone syllable stimulates growth in body tissues glucagon promotes the breakdown of glycogen to glucose insulin promotes the conversion of glucose to glycogen both are these are secreted by the pancreas estrogen and progesterone we'll get into that just now these help with the maturation of egg cells and the building up of the uterus lining or endometrium thyroxine which is secretly secreted by the thyroid helps to regulate metabolism and growth within the body so some differences between nubus and endocrine systems and action will include well firstly transport medium the nervous system uses neurons nerves and neurotransmitter chemicals the endocrine system secretes their hormones into the bloodstream the signal carrier for the nervous system is the electrical impulses but the endocrine system is with hormones secreted from these ductless or endocrine glands the transmission speed of the nervous system is very fast because it uses electricity the endocrine system is slower because it relies on a bloodstream to get the hormones around the nervous system has a more short term response effect so typically what happens as a response is short term is not long lasting and the endocrine system is either prolonged or long term let's say for example in puberty the effects of the hormones last for several months or years reproductions reproduction is the production of new individuals or offspring from parent individuals we are two types asexual and sexual a sex reproduction involves one parent it typically occurs in bacteria protozoa and some plants and animals the example would be starfish sea anemones and yeast the offspring dna is identical to the parent as cell division of mitosis occurs that occurs when there's only one television and one parent cell splits into two daughter cells sexual reproduction on the other hand involves two parents a mother and a father and these produce gametes or sex cells in the case here the father produces sperm cells the mother produces egg cells and these occur due to a process called meiosis amiosis basically halves the amount of chromosomes in these gametes when these fuse or when fertilization occurs it forms a zygote and then that eventually becomes a fetus and a baby here we have the male reproductive system feel free to pause the video to look at the labels but let's go through it here the test is secretly hormone testosterone and this helps to facilitate spoon production this is held within the scrotum now the scrotum is a sac that holds the testes and this can change position dependent on temperature because spoon production occurs at a certain temperature and of course this is a maximized spoon production so for example in cooler temperatures the scrotum would move closer to the inside of the body for warmth so next we have the prostate gland and the seminal vesicles and these help to produce semen for the transport of sperm cells into the vagina and uterus sperm is different from semen because sperm is actually the the cells that will swim in the liquid semen so upon ejaculation sperm cells are released from the vast difference this is called the sperm duct these connect the testes to the prostate and eventually the sperm cells will swim out of the urethra so about 200 million sperm cells are released and an egg can only be fertilized by one spoon cell here we have the female reproductive system which is thankfully not as physically complex as the meal reproductive system so here egg cells are released from the ovary once per menstrual cycle these egg cells are transported along the fallopian tubes or the oviducts and they are swept by tiny hairs called cilia along the fallopian tubes so it is here this position here where the sperm may meet where the egg and fertilization may occur for them to fuse into our zygote so if fertilized the egg is going to implant on the uterus wall or the endometrium to become an embryo or fetus this is where it's going to develop a placenta and amniotic sarcoma umbilical cord the cervix separates the vagina from the uterus and the cervix would dilate during childhood to allow the passage of the fetus it would also dilate during menstruation so the egg is released from the ovary during ovulation and during this time hormones called estrogen and progesterone which are secreted from the ovaries allow the rapid division of cells in uterus lining this would cause uterus lining to thicken so during fertilization the sperm cell dna is going to fuse with the egg cell dna that's going to form a zygote that would eventually become a fetus but in order for that to happen the zygote has to implant on the endometrium or the uterus wall think of it as planting a seed in soil so implantation of the zygote occurs to allow the formation of three embryonic structures as mentioned before the placenta the umbilical cord and the amnion so during pregnancy or gestation these three embryonic structures are gonna help with the growth and development of the fetus so the placenta contains many blood vessels that transport nutrients such as glucose and amino acids oxygen and antibodies from the mother to the fetus it would also remove any waste material like carbon dioxide and urea from the fetus the umbilical cord is going to allow the transfer of materials from the placenta to defeat us so the umbilical cord is connected to the navel here and this is the bridge between the placenta and the fetus the amnion contains amniotic fluid and this acts as a shock absorber basically it helps to prevent defeaters from being injured by external collisions or trauma let's say that the mother was to get hit into her belly this amniotic fluid is going to absorb the force it also supports defeat us against gravity helps the development of limbs and it also helps to regulate its body temperature because most of it is water so during childbirth what's going to happen here is that amniotic sac is going to rupture an abdominal and uterine contraction is going to begin occurring in the uterus wall what actually initiates those contractions here's a hormone called oxytocin and more and more of that hormone is produced during labor so then the baby is pushed out through the cervix remedy cervix is gonna dilate it's gonna become wider and crowning is gonna occur as the head emerges through the vagina contractions are gonna continue to push the baby head first there are gonna be more and more contractions even after childbirth because the placenta also has to be expelled from the vagina this is called the after boot prenatal and postnatal care prenatal refers to events before birth postnatal for after bit prenatal care includes adequate diet this is for the mother this includes the addition of proteins for growth and development iron red blood cell and hemoglobin production calcium and vitamin d for bone formation frequent medical visits so this includes ultrasound monitoring for the heart rate and monitoring of other organs as well to ensure that there are no tumors or no deformities um the avoidance of drugs this includes nicotine alcohol and any non-prescribed drugs should be generally avoided because whatever is in the model's bloodstream is likely to enter the fetus's bloodstream post-needle care would include breastfeeding this is to provide nutrition and antibodies to defeat to the baby in this where we are baby in this case not a fetus and this is called passive immunity and next we have immunization this would include vaccines and this is to lead to communicable infections for example measles mumps and rubella so what are the effects of smoking and alcohol while pregnant well of course these should be avoided because the baby can be in terms of smoking the baby can be born with a nicotine addiction and can experience withdrawal symptoms even though the baby wouldn't even know what a cigarette is nicotine also constricts blood vessels in the placenta this means that any nutrient and oxygen transfer to the fetus would be limited and of course this could lead to the baby being born prematurely and underweight the tiny lungs would limit oxygen intake by any mother and of course the babies of the fetus's cells would not respire properly alcohol should be avoided while pregnant because they have this syndrome called fetal alcohol syndrome which results in mental and physical underdevelopment and there's also alcohol poisoning or defeaters because as i said whatever goes into the mother's bloodstream some of it is gonna go into the baby's bloodstream there are many hormones involved in the menstrual cycle the four amine ones are fsh lh estrogen and progesterone let's start with fsh or follicle stimulating hormone the egg cell is usually surrounded by a casing called a follicle or graffian follicle fsh stimulates the growth of that follicle and this here would help to hold the egg cell before ovulation lh or luteinizing hormone when there is a surge of luteinizing hormone this is going to trigger the rupturing of that follicle and allow the egg cell to be released this is when ovulation is going to occur now all this time here we would have had estrogen being released this would have helped to take on the uterus wall or the endometrium for implantation in case the egg gets fertilized estrogen also helps to stimulate the increase of luteinizing hormone progesterone is released from the follicle after it releases the egg and this helps to maintain the thickness of the uterus lining let's say that a woman that the egg gets fertilized but the uterus is not ticking off that means that the egg even though it is fertilized would not be able to be implanted and cannot develop things like umbilical cord and a placenta which means that it would not develop into a fetus there are three main phases of the menstrual cycle the follicular phase the luteal phase and at the end of the luteal phase there is menstruation let's start with the follicular phase as you see here in the follicular phase the graphion follicle that contains the egg we can see that the little circle inside here as the egg will develop on material due to the secretion of fsh so fsh is going to stimulate an increase in estrogen so estrogen is the yellow line and also it's going to trigger a surgeon lh that is a red line there seen it so you see in here he surges this big peak here so the surgeon lh is going to trigger ovulation ovulation is when the follicle ruptures and releases the egg as seen here this occurs around day 14 of the menstrual cycle basically in the middle of the cycle so in this case here the egg is released from the ovary and that marks the end of the follicular phase the luteal phase occurs after the surge in luteinizing hormone lh so at this point here the lh levels begin to drop they begin to decrease the follicle after it has has released the egg turns into something called a corpus luteum that is what you see in here this corpus luteum is going to secrete progesterone and this progesterone now is going to help to maintain the thickness of this endometrium or uterus lining this is in case the egg gets fertilized it can implant on the stick on uterus lining so these progesterone levels will stay high for a few days and implantation is possible at this time now during menses or menstruation same thing this is at the end of the luteal phase what happens here is that the corpus luteum which would have been the follicle would have broken down and because this has broken down it's not going to release progesterone anymore you'll notice that when this is present progesterone levels go up when this has broken down progesterone levels go down while this is also correlated to the thickness of the uterus lining of the endometrium so when this these progesterone levels rapidly decrease that leads to a breakdown in uterus lining so what happens now is that your trust wall begins to shed and the unfertilized egg and the endometrial material are shed through the vagina fsh and estrogen levels actually slightly increase during this phase [Music] contraception so also called bird control and this refers to any method that prevents pregnancy from occurring so why you'd want to do that it was basically used by families that wish to avoid the financial and emotional strains of reason a child raised not child are easy but is also used to limit population growth in countries and combat overpopulation so this can occur via two armed two ways well contraception is the prevention of fertilization of the egg and examples of these types of matters would be condoms urida method vasectomies and tubal ligations but there's also anti-implantation methods where fertilization of the egg occurs but the fertilized egg cannot be implanted on the endometrium so examples of this would be iuds or intrauterine devices or morning after pills let's go into how these work so first let's start with barrier matters of contraception so condoms prevent sperm from entering the vagina because basically they cover the penis and urethra diaphragms prevent spoon from entering the uterus and these also protect against sexually transmitted infections if used correctly next we have the natural metadata method basically this involves the girl early woman pinpointing the day or the series of days where she thinks she's gonna ovulate in time of ovulation and is simply going to avoid intercourse at that time this is very unreliable because the period of ovulation that that that window actually changes dependent on situations of stress changes in diet and changes in environment they are surgical methods so there are two in particular vasectomies and tubal ligations so for a vasectomy this involves the ligation which is the cutting and tying of the vast difference of the sperm duct and this would prevent sperm from reaching the urethra so spoon cells are still produced but they are simply not released during ejaculation the male in this case is sterile tubal ligation is the tying on cutting of the fallopian tubes this would prevent the eggs from being released into the uterus eggs are still produced but they cannot be fertilized because the sperm cells cannot reach the egg cells these both have very high success rates but they offer no protection against sexually transmitted infections hormonal matters of birth control or build control pills have different modes of action and this could include to suppress ovulation so no egg is released at all to take on the cervical mucus so that sperm cells um it acts as a barrier for spoon cells so they cannot enter the uterus and it could also help to reduce endometrium thickness so that no implantation occurs basically there's no there's no soil to plant the seed there are numerous side effects with using bird control pills so typically only girls that reach a certain age or have a doctor's prescription should take them these side effects would include things like mood swings fatigue and bloating or weight gain meal contraceptive pills are not i mean any works but they're not out in market yet but how these could work um potentially basically um they could reduce testosterone levels any men and decrease spoon production they can make the sperm immobile make them unable to swim or they can tick on mucus in the vast difference so when the man does ejaculate um very little sperm cells are released now we have to remember about birth control pills for women is that they have to be taken at the beginning of the cycle and they have to be taken every day for them to be effective next we have morning after pills or emergency contraception this would occur after fertilization has taken place or after sexual intercourse has taken place there are various types that exist so the mechanism of action involves delaying ovulation or causing changes in the endometrium that limits implantation if the if it has already been fertilized the egg um but what do i mean by delaying ovulation well sperm cells can live up to two to three days within the uterus so let's say that the woman has sex by monday and she is ovulating tuesday or wednesday she can still get pregnant um but let's say by thursday those spoon cells would die then he could delay ovulation to friday so that by the time she releases the egg they always themselves would have died by then so this must be taken up to three days after fertilization occurs or three days after the woman has had sex despite the name being morning after other blood control pills must be taken every day from the start of the cycle to be effective so here we have the mechanical method now which is the use of iuds or intrauterine devices these are small t-shaped pieces of plastic or copper which stimulate the production of white blood cells to destroy the sperm cells sometimes the iods would produce toxins that would be you know that would be poisonous to these spoon cells they could also produce hormones that would tin the endometrion to prevent implantation from occurring abortion refers to the premature termination of a pregnancy basically this is not a contraceptive method because this does not prevent pregnancy this prevents childhood so we are two different types spontaneous abortions also call miscarriages occurred due to some internal issues such as a direct trauma illness or chromosomal defect in some cases if the mother is malnourished there will be a miscarriage these do not involve the action of a doctor or clinic clinical abortions occur when the pregnancy is deemed undesirable by the mother or is a threat to her life so the fetus is extracted from the uterus by a doctor in countries that are pro-life they believe that life starts at conception basically when the egg gets fertilized in those countries this is deemed unethical but it is sometimes justified in cases of rape incest or when defeaters poses a fatal danger to the mother's life health and disease well according to the world health organization or wh o health is defined as the complete state of physical mental and social well-being disease is defined as the impairment of the functioning of the body and mind so diseases can be communicable or non-communicable communicable means that they can be spread from one individual to another they're infectious and they are caused by pathogens non-communicable means that they cannot be spread from one individual to another they may be caused by a lifestyle or may be inherited so there are many categories of disease however it is important to keep in mind that any one disease cannot be placed in a single category so for example diabetes could be considered chronic because it is a long-term disease but it also be could be considered physiological because it is caused by malfunction in an organ or system in this case here the pancreas so physiological diseases also include coronary heart disease and asthma mental diseases are those that occur due to the impairment of the mind or the tissues within the brain these include alzheimer's disease clinical depression and neurosis other examples of chronic diseases would be chronic bronchitis and asthma infectious diseases are all come in a couple and this could be caused by the introduction of pathogens in the body this would be viruses bacteria protozoans or fungi examples would be dengue fever which is caused by virus malaria which is caused by protozoan and cholera which is caused by bacteria social diseases are caused by an individual living or working within an environment prone to contamination by pathogens or having no access to a balanced diet let's say that the only water that they have is from a river that is often polluted so examples of this would be cholera dysentery scurvy rickets and night blindness degenerative diseases are caused by the gradient loss of function of tissues and organs examples would be alzheimer's disease and osteoarthritis due to the wearing array of cartilage deficiency on nutrient deficiency diseases occurred due to the lack of a particular nutrient in the diet examples would be quasi or core a lack of protein scurvy or lack of vitamin c night blindness a lack of vitamin a or rickets a lack of vitamin d or calcium hereditary diseases are caused by inheriting alleles that are going to translate to malfunctioning proteins basically your dna is going to tell your body to operate differently and to form different structures that do not work or function as well example would be sickle cell anemia which forms deformed or sickle-shaped red blood cells hemophilia which affects blood clotting and cystic fibrosis which affects the lungs and allow the buildup of mucus lifestyle diseases or self-inflicted diseases are those that occur due to the intake of excess nutrition or drugs or that occur due to a sedentary lifestyle these include liver cirrhosis due to the overconsumption of alcohol lung cancer due to the exposure to smoke and coronary heart disease due to uh improper diet with lots of fats and cholesterols signs and symptoms so signs are observable or testable changes that occur in the body when afflicted with the disease these are things that you can see so vomiting diarrhea fever rashes runny nose symptoms on the other hand are non-observable changes that occur in the body when afflicted with a disease these are things i cannot see and the patient must explain these to their physician examples would be fatigue dizziness nausea headache joint pain so these are some common terms that we're gonna come across here antigens are foreign substances for example viral proteins that enter the body and trigger an immune response i like to think of antigens as the burglar alarm within the body antibodies are proteins produced by lymphocytes which is a type of white blood cell and these would help to combat antigens and pathogens antitoxins are specific antibodies that eradicate toxins that enter the body antibiotics are oral medication or ingested medication that are used to treat bacterial infections not viral infections antiseptics are medications that is applied to bodily surfaces to treat or prevent infection let's say that to get a cut on your skin you will put an antiseptic on that disinfectants are chemical agents such as bleach or hand sanitizer that is applied to material surfaces to kill microorganisms as markers when bronchioles become constricted and quickly become clogged with mucus they are usually triggered by inhaling dust pollen or smoke or by excessive physical activity a muscular relaxer must be used in an inhaler to dilate the airways to allow airflow signs and symptoms would include wheezing shortness of breath and bronchospasms bronchitis occurs due to the irritation of the airways and the lungs by air pollution example when in healing smoke or when there is a bacterial or viral infections same way with asthma excess mucus is produced and this would foster the growth of bacteria which will give rise to opportunistic infections such as influenza and pneumonia antibiotics can be used if there's a bacterial infection involved signs and symptoms would include coughing shortness of breath and excess mucus cholera and gastroenteritis are caused by the ingestion of harmful bacteria that come from human feces example would be vibrio coli and e coli this can be due to drinking sewage contaminated water or when flies deposit fecal particles or bacteria only food so extreme bouts of stomach pain vomiting and diarrhea may ensue and this could lead to dehydration and even death so to prevent these two diseases food should be thoroughly washed and cooked water should be boiled or chlorinated which will kill the bacteria after filtering which will remove any sediment food should be covered and kept far from flies and hands utensils and dishes should be washed before and after meals should avoid drinking water from contaminated wells or rivers so these diseases can be treated with antibiotics intravenous drips and restoration of fluids and electrolytes cancers refer to a group of diseases where cells in a certain organ of tissue uncontrollably divide so age influences cancer risk as it is usually formed due to a random mutation but there are also chemicals or agents called carcinogens and these are capable of inducing cancer example would be cigarette smoke particulates ionizing radiation so for example x-rays or ultraviolet rays from the sun food additives and viral rna so for example from hpv or the human papilloma virus which causes cervical cancer in women so cancers typically occur in the lungs the prostate the pancreas the ovaries the breasts the uterus the civics and the colon stis or sexually transmitted infections are communicable diseases that occur when a pathogen is transferred by a sexual contact examples of this will include aids which is caused by hiv syphilis which is caused by bacteria tryponema palidum gonorrhea which is caused by a bacteria nesteria gonorrhea cervical cancer which is caused by the human papilloma virus or hpv and chlamydia which is caused by bacteria just some key symptoms here of stis chlamydia the experience burning during urination and vaginal and penile discharge syphilis there's body rashes on the back sores of the feet and palms fatigue he allows weight loss and nervous system damage could occur in newborns or miscarriages in gonorrhea there's a mild fever but is usually characterized by burning during urination and the leakage of pus from the urethra hiv and aids results in rapid weight loss hair loss dark lesions on the skin called kaposi sarcoma and chronic diarrhea so once again to remind you cancer is a disease that causes the uncontrollable division of cells in a tissue or organ in this case your cervical cancer is in the cervix so cervical cancer is caused by the human papillomavirus or hpv and this is transmitted during sexual intercourse now because men don't have a cervix they are not affect afflicted by hpv and of course they cannot get cervical cancer but they can't pass it on to women so men who have poor hygiene and are uncircumcised have a higher risk of carrying and transmitting hpv because it usually resides within the foreskin of course you know circumcision is the cutting of the foreskin so cancers are treated by firing radioactive rays at the affected area this is called radiotherapy and this usually results in nausea hair loss and weakness hpv can be detected by doing a pap smear where swab sample is taken from a cervix it can easily be prevented by having male partners wear condoms or simply obtaining the hpv vaccine so good hygiene prevents communicable diseases such as influenza and cholera and covid19 more recently by hand washing and dishwashing so it clears harmful bacteria or bacterial material and viruses away from deposits on the skin and airways now it also helps to eliminate body odors and ensures social acceptance basically we smell and good it prevents fungal diseases such as ringworm and athlete's foot and washing genitalia helps reduce the spread of hpv from men to women brushing your teeth regularly with fluoride toothpaste and flossing would help prevent tooth decay hiv stands for human immunodeficiency virus aids stands for acquired immune deficiency syndrome the virus is transferred via semen vaginal fluids blood transfusions and breast milk hiv infects a type of white blood cell called lymphocytes and these infected cells help hiv multiply and proliferate and infect other lymphocytes now when the t lymphocyte count drops below 200 per millimeter cube of blood the patient is said to have aids in this case here the person is severely immunocompromised as a severe immune deficiency as acquired over time so hiv is very difficult to detect and produce a vaccine for antibiotics are useless against viruses antivirus has a high rate of mutation so basically when a person has aids they have a very low white blood cell count and as a result they're gonna have a very hard time fighting off other opportunistic infections caused by viruses so for example something as simple as influenza could evolve into something more serious like pneumonia so how can hiv spread be prevented or reduced well there's a use of barrier matters of contraception so for example condoms and diaphragms limiting the number of sexual partners are being faithful to a single partner regular hiv blood screening education on safe sex for the young and the underprivileged the use of antiretroviral therapies for example use of the medication ezt to minimize symptoms and spread there's also specific medication therapy that's used for pregnant women to limit the spread to their babies there's also reducing stigma and discrimination against hiv-positive people so that they are more likely to get tested and they'll know well what's the next steps at least in order to prevent further infection and put a spread of the the disease factors that affect regional distribution of aids include one culture some cultures discourage use of condoms some encourage multiple partners and some cultures have a high stigma against hiv and this would lead to hiv patients being unwilling to admit their hiv status or get tested with the risk of you know not getting a job or being discriminated against many peers there's a long incubation period for hiv so since hiv may not be detected by blood tests until three months into incubation and hiv positive person um may not know that they have hiv yet and can unknowingly spread it during that time ease of travel so whenever there is a large number of tourists especially those partaking in sex tourism with locals the virus can quickly spread to local populations then there's poverty and lack of education this encourages sex work which will facilitate spread have done irresponsibly there's a lack of antiretroviral health care in some countries and a lack of educational programs that would inform about hiv transmission and prevention obesity is defined as having a bmi over 2t bmi stands for body mass index and it can be calculated by taking one's mass in kilograms and dividing it by their height in meters and squaring that value now bmi is not the best indicator of health because according to this index here a bodybuilder might be classed as obese because they would have a high muscle mass compared to their height so obesity typically occurs due to the overconsumption of foods rich in carbohydrates refined sugars and energy dense lipids fats and oils so when consuming excess the molecules are converted for storage and they become deposited in fatty tissues being in the skin and these can be deposited below the dermis as i just said or around organs when it's below the dermis it is caused subcutaneous fat and around organs it is called visceral fat which is very very dangerous and this could increase the chances of developing non-communicable diseases such as type 2 diabetes cardiovascular diseases such as coronary heart disease kidney failure and fatty liver disease so let's take a look at diabetes type 1 and type 2. now typically what would happen is that you would eat your sugary foods your sugary meals your pancreas would secrete insulin and that insulin is going to bind to the cells and allow the glucose from the bloodstream to enter the cells and thus your blood glucose level is going to drop so a person who has type 1 diabetes they are going to produce little to no insulin so as a result now the glucose cannot enter the cells this is because insulin is like a key that would open my door the door being the cell membrane of the cell so if there's no key the door cannot open so this form of diabetes is genetic and is usually diagnosed in childhood patients with this type of diabetes have to take insulin injections all of their life type 2 diabetes occurs when the patients produce insulin but the insulin receptors on the cells do not respond to that insulin so they say that they have insulin resistance so in this case here is like the key is still there but the key is not working properly so in this case here um this is due to accumulation of fat around the pancreas or sedentary lifestyle so if the patient exercises frequently the insulin could then bind properly to the cell membrane and you would have less insulin resistance or they could take oral medications such as metformin or they can simply reduce their carbohydrate intake so here we can see a graph showing blood glucose concentration versus time so let's say that the person here eats a meal at zero hours right right at the beginning of the graph and let's look at the person who's normal we can see that their blood glucose level is going to go up because they are going to absorb that glucose into their bloodstream from the intestines and then there's going to be assimilation of that glucose into the cells this is when the glucose would exit the bloodstream and go into the body cells this is going to cause the blood glucose level to drop and then return to normal now for placement diabetes whether b diabetes type 1 or type 2 the blood glucose level is going to be naturally higher and this is because there's going to be delayed assimilation when that person eats a sugary meal their blood glucose level is going to go up like this especially if they are eating very large meals blood glucose level is going to rise as that as that gets absorbed into the bloodstream now it's going to take much longer for the glucose to enter the cells because of insulin resistance or because of lack of insulin so diabetes whether type 1 or 2 restricts the movement of glucose from the blood capillaries into the cell cytoplasm to the cell membranes this is going to result in fatigue and dehydration and in the worst cases to see necrosis that's the death of tissues and amputation and infection so in diabetes the assimilation of the uptick by the cells of glucose is delayed so that glucose in a blood stream will not be taken up by the cells especially when you have a very large meal of carbohydrates or sugars and the blood glucose level or set point is higher for diabetics which is more than 130 milligrams per deciliter but to put this on a nutshell here if you are diabetic either you're not going to produce insulin which is like the key to open the cell for the glucose to enter or the key is not going to work properly so you're going to have insulin resistance the key is not going to work any glucose just remains in the bloodstream this could be very dangerous to the tissues or cells around those capillaries so factors that affect the original distribution of diabetes would include well diet and obesity due to the prevalence of fast food being the convenient option or the prioritization of foods high in lipids and refined carbs examples would be like doubles and trinidad sedentary lifestyles where you have long hours of office work and no time for outdoor recreation prenatal malnutrition or gestational diabetes which means the mother could pass on the risk to the 80 child and they have age ethnicity and genetics which the risk increases with age and people of african and asian descent are observed to more commonly developed type 2 diabetes so atherosclerosis refers to the condition where plaques form and adhere to the arterial walls and this would reduce the lumen size basically the passageway for the blood to flow the plaques are made up of deposits of cholesterols and chemicals from tobacco smoke a high pressure flu now could transform the plaque into a trembus or blood clot this could lead to a heart attack if this blood clot was to get lodged in into a coronary artery in the heart so as previously said if the troubles was to fracture and enter coronary artery which are those that surround the heart the heart's muscles will not receive oxygen enough oxygenated blood so they will not be able to beat properly so this would eventually lead to a heart attack and potential death if it's not treated soon enough so remember this decrease in lumen size means that there's less area available for blood flow unless the heart applies more force and this could lead to elevated blood pressure or hypertension basically if you are above 140 or 90 milli millimeters mercury of pressure lastly a stroke could happen similar to with the heart but if the carotid arteries that carry blood to the brain are blocked okay so just to give a basic definition here a pathogen is a disease-causing microorganism i said before this could be a bacteria a virus a protozoan or fungus a vector is an organism that can transport a pathogen from one organism to another so this could be flies it could be rats or it could be mosquitoes so dengue fever is caused by a viral pathogen but the vector fit is the female adult aedes aegypti mosquito these don't at least suffer from dengue but they can transport that virus from one person to another so how this happens is that the mosquito would inject its mouth parts or its proboscis into the skin of an infected person and they would draw the infected blood from a vessel that would contain a dengue virus the mosquito would secrete saliva that would enable this to happen without clutton so if the bitten person has a dengue virus the mosquito is going to draw it in and become a vector so if the mosquito then bites an uninfected person is going to secrete the saliva and that saliva is gonna have the dengue virus in it and it's gonna inject the mold parts and the virus is gonna enter the person's capillaries as a result so the mosquito has transmitted the virus from one person to another person all right so here we have the mosquito and the house fly life cycle let's start with the mosquito so we have the adult mosquito which is the active form as a is a flying terrestrial insect and these lay eggs and stagnant water sources not flowing water like rivers but it will be like ponds or wherever you have garbage that collects water let's say in tins and containers and tires so the egg is a dormant stage and this typically lasts about one week and after one week they would hatch and become larvae so these larvae now last about about two weeks before they become a pupa so the larvae is also an active stage which means that they move around but they can't be eaten by any like anything in the water sources if there's anything like fish for example the pupa is a dormant stage which means it doesn't really move around after a few days maybe two days it hatches and metamorphosis is complete and the baby mosquito from the eggs would become an adult mosquito which can then go on to leave more eggs and the mosquito has a lifespan of about three to four weeks the whole splendid and you see is very similar it's just that the diagrams look a little different the adult leaves eggs [Music] they are thoughtless eggs but in case here is not in stagnant water sources it may be close to our food source basically like our own you know in garbage and these hatch to become larvae or as we call them maggots these would then develop into pupil and then an entire adult so other vector borne diseases would include malaria which is caused by a protozoan called plasmodium fasciparen and it is transmitted by anopheles mosquitoes so the protozoans when they enter the bloodstream they would live in the red blood cells and they would mainly cause inflammation in the living brain chikungunya and zika two other mosquito-borne diseases which are carried by the aries aegyptine as a vector and they mainly result in high fevers and tissue damage to fetuses in pregnant women leptospirosis bacteria is transmitted by a rat urine and house flies transmit bacterial pathogens for cholera when they you know they land on food and they could deposit fecal particles onto their food so how do diseases impact society well first we have the economy lisa strain on state funded medical care money far away in his campaigns and medical ppe there's personal protective equipment there's a reduced labor force as a result and there's an overall drop in productivity businesses can be affected by lockdowns if the disease is widespread and its communicable trade relations are affected because there's reduced income from exports due to drop in productivity and there's tourism but is affected by the stigma of disease basically nobody wants to go somewhere where they could get a disease food availability is affected because food shortages could occur if the agricultural sector is impacted horsehold income due to privatized healthcare medical bills the unemployment especially the breadburner of the family gets um gets sick the quality of life decreases due to emotional and psychological tools of illness and quarantines we all know how it was during the lockdowns on the other hand though you can have positive awareness of the disease if it is widespread enough it may influence those without the disease to make lifestyle changes and take extra precautions such as washing hands more often perhaps to exercise more often so prevention and control of viral infections we have three factors we're going to look at social factors biological factors and economic factors so the social factors would be well quarantined um quarantine is basically you get sick you stay home and this limits the spread of viral infection and may have a severe effect on businesses and household earnings as a result safe sex which ensures the use of condoms and limiting partners of course prevents sdi spread biological factors the use of ppe so surgical masks prevent droplet spread and sterilization of equipment vaccination reduces the incidence and the spread of infection good hygiene such as regular hand washing disinfectants and antibacterial soaps help to prevent or limit common a couple disease spread regular blood screening can limit the spread of pathogens such as hiv and antiviral drugs and monoclonal antibodies can be used to treat some viral infections uh monoclonal antibodies has been used to treat cloven 19 for example so economic factors would include pest control and this would be for example removing stagnant water sources and keeping refuse from piling up would also reduce the chance of vector breeding this is called sanitary control insecticides brain programs or chemical control introducing fish to ponds or biological controls can eradicate mosquito larvae and eggs mosquito nets and coils or act as mechanical controls there's awareness campaigns money has to go into doing this education about limiting spread and infection and there's the cost of preventative medication so for example surgical mass ppe private doctor visits blood screening mammograms biopsies for detecting cancer even vaccines cost money to import them here we have some methods of preventing pathogen growth we've spoken about most of these already so feel free to pause the video and just read the functions [Music] let's look at the types of immunity so immune responses happen due to the exposure of foreign substances or antigens that are attached to pathogens so think of antigens as i said as the body's burglar labs was these entire bodies gonna stimulate our immune response so immunity occurs due to the production of antibodies from lymphocytes that's a type of white blood cell so immunity can be passive or active so passive means if antibodies are introduced from an external source so for example from breast milk or if you inject an antibody serum into the body active immunity on the other hand is if the body is allowed to produce its own antibodies and memory cells as a response to the infection such as a multi-dose vaccine or if you just get naturally infected that's called natural immunity all right so let's break down the four types of immunity so the first type here is naturally acquired active and this occurs when there's an immune response to pathogen exposure so this is just you walking around outside and you also get the flu from somebody is highly unlikely that you would get that same strain of flu the next time this is because your body has developed antibodies or lymphocytes that develop antibodies and memory cells that are gonna remember that disease so it is unlikely that you'll get affected by it twice a good example of this would be chicken poxy developer natural acquired active immunity against it it's unlikely that you're gonna get it a second time natural passive immunity um occurs due to a transfer of antibodies that occurs from mother to offspring whether it's fetus or baby so this could be either truly breast milk or truly mother's placenta artificially acquired active immunity is long-term immunization obtained merely through a vaccine so it's due to intentional exposure to the antigens remember a vaccine or you introduce a weakened version of the pathogen into the bloodstream your body responds to it produces antibodies produces memory cells so you're unlikely to encounter it or be affected by it a second time artificial passive immunity is a short-term immunization obtained from the injection of antibodies into the bloodstream such as in a serum this is using a treatment and there are no memory cells that develop to a given example let's say that he was to get covet 19 and he didn't get a vaccine well of course the vaccine law would be useless because you already have the disease the vaccine is a preventative measure so what can you do well there's something called monoclonal antibodies which is a serum that can be injected into the bloodstream that can potentially fight off the virus but this is short term because this is not actually teaching your body how to find the disease it's just bringing in reserve soleus to fight off our enemy so let's take a closer look at vaccines here so vaccines provide artificially acquired active immunity they stimulate the production of antibodies due to the intentional introduction of an antigen into the bloodstream so they are usually multi-dose because they produce multiple immune responses and they are used for communicable diseases such as measles hpv and rubella so vaccines have numerous modes of actions this could include live attenuated vaccines and these contain a weakened form of the pathogen inactivated vaccines contain pathogens that cannot reproduce subunit vaccines contain only a detectable component or protein of a pathogen thus a small part of a diabetic can detect an mrna vaccine so example phasor vaccines and what they do is that they contain instructions so that your body can build that part of the virus within you i know that sounds a little dangerous but basically is only synthesizing a small part of the virus so that your body will know what it looks like [Music] so what are some advantages and disadvantages of using vaccines so first of all vaccines are often successful at stimulating antibodies and memory cell production so it often reduces the severity of the infection so if you even if you do get infected you would fight it off fast enough that you don't get the full blower signs and symptoms it also reduces incidence rate so less people will get potentially infected and spread the pathogen to the uninfected or vulnerable this is called hood immunity disadvantages well viruses mutate orphan and produce variants we know that with delta or micron for example with covid and these are different funny versions that are found in vaccines in this case series vaccine might be useless or might not be as effective so vaccines may also cause severe allergic reactions this is called anaphylaxis this is rare however lastly the immunocompromise which would be the second elderly and very small babies may be at risk of getting ill with the vaccine drug abuse well a drug is an externally administered substance that alters the body's physiology and they can be prescribed such as painkillers sedatives for sleep and medical marijuana what drug abuse occurs when the use of the drug leads to physiological or psychological harm to the user their family or society at large it leads to drug dependency withdrawal symptoms when a drug is not used or possibly overdose and the progressive decrease in response to a drug is called tolerance so basically the first time that you used to take a drug it would be highly effective if you take it 10 more times it's going to get less and less and less effective you see that you build up tolerance to the drugs so there are four main classifications of drugs they are stimulus which um so there are four main classifications of drugs they are stimulants which increase nervous transmission examples of this would be cocaine and metamphetamine or crystal met depressants which decrease nervous transmission they slow you down basically examples of this would be alcohol and codeine hallucinogens which cause hallucinations examples would be marijuana ecstasy lsd and pcp and we have narcotics which are used to treat pain examples would be heroin and morphine and fentanyl so even if you have prescribed medication like antibiotics these can be abused or misused so patients who do not complete the full course of an antibiotic prescription will run the risk of having antibiotic resistant bacteria develop in their bodies i'll give an example let's say that you your doctor prescribes a two week course of antibiotics you only take it for one week and you you feel like you're feeling better so you stop taking it if you only take it for one week the weakest bacteria is gonna die but the strongest ones are still gonna be there so most of the normal bacteria are gonna die but the resistant bacteria these are the lighter colored ones in this diagram these are going to start multiplying because they're not taking the antibiotic anymore and these antibiotic resistant pathogens are going to keep multiplying and as a result now the disease is going to come back worse than before the same antibiotic is not going to be as effective so and remember some antibiotics have addictive properties um which can make the user experience withdrawal when the course of treatment ends so what is the difference between psychological and physiological drug dependency well let's look at two case studies here wayne is 16 years old and smokes cannabis with his friends he often goes without cannabis for days and a time with no ill effects however after a week has passed he feels a strong urge to smoke especially when he feels depressed or bored so wayne is showing psychological dependency and this is usually characterized by lack of strong withdrawal symptoms so he doesn't actually get any sickness when he stops the ability to grow prolonged periods without the drug in this case he can go after like a whole week and his drug abuse is usually influenced by by social factors or by boredom physical or physiological drug dependency however let's look at sandra so she's 40 years old and uses heroin in two to four injections four to 12 hours apart when she goes for longer than 12 hours without heroin she she feels sick and becomes anxious so sandra is showing physical or physiological dependence because she has strong cravings she has withdrawal symptoms if the drug is abruptly stopped for short periods and her symptoms wilson as the frequency of the drug abuse increases in terms of alcohol alcohol or the scientific name eternal is at the present so when consumed in excess it can heavily impair another transmission and can lead to dehydration of tissues there are many social consequences of alcohol abuse so one is car accidents due to the decreased reaction time impaired motor skills and judgement wouldn't be able to react on time violence and fighting due to the loss of inhibition altercations may escalate family breakdown due to aggressive behavior domestic violence child neglect if the breadwinners alcoholic and becomes unemployed could lead the family into financial turmoil academic neglect for younger people and students there's the inability to concentrate they can neglect their grades there's absenteeism from school and there's poor sexual intercourse decisions there's reduced inhibition they might have sex with somebody that you really don't want to have sex with the risk of stis and undesirable pregnancies there are many health consequences of alcohol abuse as well so for this is of course imperial nervous transmission so since neurotransmitter activity will slow down reaction time is gonna decrease and perception becomes distorted so example you're gonna have reduced motor skills and blu-ray vision um the cerebrum and the cerebellum in the brain are gonna get affected dehydration is gonna occur because adh which is usually released by the pituitary gland in the brain is gonna get suppressed adh allows water to get reabsorbed from the kidneys back into the bloodstream so less water is gonna get reabsorbed into the blood this is gonna lead to dehydration um frequent urination and hangovers there's an increased risk of cardiovascular diseases because blood vessels are actually constricted by alcohol and this could increase the chances of a blood clot dropped here on an ensuing heart attack or stroke in terms of cigarettes um cigarettes contain tar and particulates carbon monoxide and nicotine so tan particulates lead to irritation in the airways and a breakdown of elastin in the lungs this would create very large airspaces in the alveoli and this reduces service area for gaseous exchange that leaves us with a bill of fluid this is called emphysema it also leads to excess mucus production in the lungs which is a breeding ground for bacteria ciliated cells are destroyed as basically cells with tiny hairs on them and this would increase the risk of bronchitis because those tiny hairs actually trapped dust and bacteria so bacteria would now enter the airways and bloodstream which could lead to other infections as well carbon monoxide is a colorless odorless gas that is in cigarette smoke and this could bind very quickly to red blood cells and it will basically occupy the species of oxygen this could lead to potential suffocation or asphyxiation of course in the case of cigarettes it wouldn't die from carbon monoxide but it would reduce the amount of oxygen being carried to the cells so even be in an environment of smokers and heal any components composes a threat so this is called secondhand smoke or passive smoking now remember cigarette smoke also contains the addictive component nicotine which is a stimulant and this increases heart rate and blood pressure pollution is defined as the contamination of the environment due to the harmful disposal of waste a pollutant is a contaminant disposed into the environment causing harm to it so we're going to look at different categories of pollution of course pollution involves land pollution air pollution water pollution and noise pollution but we're going to look at it as domestic pollution industrial pollution and agricultural pollution domestic pollution comes from households and this will include detergents litter or refuse or exhaust from cars industrial pollution involves heavy metal oil being dumped into water or tumor pollution tumor pollution it could basically occur due to gases very hot gases going into the atmosphere or very hot chemicals being dumped into water this of course could affect any life living there agricultural pollutions occur when fertilizers and pesticides run off into water sources so sewage runoff to water supplies can lead to color and typhoid because they may contain faecal particles and bacteria combustion of refuse can lead to respiratory diseases like bronchitis basically when you burn rubbish excess carbon in the atmosphere because when this burns it releases carbon dioxide also also leads to climate change rises in temperature and sea level the accumulation of waste on land can provide breeding grounds flies and rats because they could live there they could feed on any trash here and they could breed here and this could contribute to higher incidences of cholera and leptospirosis runoff of any sewage or fertilizer into water sources can lead to eutrophication or algal blooms basically this is the overgrowth of algae so these contain fertilizers contain nitrates and phosphates and these facilitate algal growths now due to this algal growth is going to use up a lot of oxygen in the water so the oxygen is going to get rapidly depleted so aquatic life is going to suffocate as a result so you know they living on the water they still need oxygen and it could also block sunlight from coming into contact with other plants prevents other plants from photosynthesizing we have two types of products here biodegradable products and non-biodegradable products biodegradable products are able to be decomposed by microorganisms in a relatively short period of time examples would be paper wood food and cloth non-biodegradable products cannot be decomposed by microorganisms or they take a very long time to do so examples would be glass plastic metal and nylon so how do we control pollution well first they are laws laws that prevent the dumping of oils and agricultural chemicals into water and laws that limit carbon emissions from factories so they also laws that prevent large gatherings in meatier areas this helps to produce noise pollution but also land pollution because wherever there's large areas there's going to be a lot of littering and garbage and this is going to disrupt animal behavior you can have cleanup crews for beaches and rivers um there's also just basic social responsibility for using little cans or if they're going to the beach take a garbage bag with to use they could take a trash home there's also the use of renewable resources such as wind turbines solar panels hydroelectric dams and there's also the use of hybrid vehicles and fluorescent lights these either prevent or mitigate or reduce carbon emissions into the atmosphere so let's look at the water cycle and let's start with water in the ocean so first this water is going to evaporate and evaporation is a conversion of water to water vapor transpiration is when water evaporates from the leaves of plants this water vapor now is going to condense on a good condensation where that water vapor is going to cool to form clouds now remember respiration also occurs and water vapor is released when we breathe out so when we exhale we also release water vapor into the atmosphere so after this water vapor condenses and forms clouds we're going to have precipitation and this is the conversion of the water vapor to water as rain or snow so when rain falls for example water is gonna run off back into streams and rivers and back into oceans this is just called runoff and lastly we have filtration which is the collection of precipitate or water that is stored in layers of rock and limestone so any water goes through the soil that is called leaching or do we test water for bacteria well first we have a sterilized cotton swab analysis dipped in the water sample or whatever sample they are testing for the swab is then rubbed against some agar gel and it typically is rubbed like side to side or is rubbed in just smaller deposits this aiga gel contains nutrients so like glucose and proteins that allow growth of the bacteria you seal the petri dish so it's securely closed and after a few weeks bacterial colonies like little spots are gonna appear and then you could observe these on a microscope to see exactly what is what how is large scale water purification done well one the water is collected from the households it's just called collection and then it's passed through a screen so screening removes large waste particles and sediment the water then flows into a sediment tank and the denser waste is gonna sink to the bottom dry sludge is gonna be transported to landfills then it's gonna flow into an aeration tank which contains aerobic bacteria these bacteria respire and they're gonna digest these smaller sewage particles as oxygen is pumped into the tank after the aeration tank the water is going to be pumped into a chlorination tank where chlorine or purification tablets are added to kill any remaining bacteria at this point here and all the water is drinkable or portable so distribution is going to occur of this portable water to be pumped back into households so to take a closer look at biological filters um which is part of the large-scale water purification system biological filters are pumped with aerobic bacteria and oxygen i said before the bacteria decompose and digest the organic matter in the sewage over time they basically use it as food and the very small particles are gonna float to the top as you see in here and this is gonna get released as effluent while larger particles settle at the base so these smaller parties larger particles sorry um that sync to the base here these are going to get returned as activated sludge to the biological filter where the whole process is going to start over again until we get less and less and less sewage in the system sewage disposal practices we are improper practices and proper practices let's look at the improper ones first improper would be just if you take the sewage and used to dump it into a water source like a river or pond for example well this could lead to eutrophication which is the buildup of algae as previously said and also if you was to take the sweden has to bury it or bypass the buried close to water sources such as wells or used to bury it closely water table the bacteria from that sewage could leach into the soil and could possibly pollute the soil and could deter growth of plants there and also could affect any animals or underground life also if there's people drinking from the well where the where the sewage is buried this could lead to colorant dysentery and typhoid so the proper practices would be to use septic tanks which would collect the sewage and waste water into large underground tanks which are pumped and disposed off on a regular basis there's also biological filters which is involved in land scale water purifications these are tanks that contain aerobic bacteria to digest sewage just went into that domestic refuse disposal so individuals can dispose of organic matter in compost boxes these contain bacteria earthworms small insects that will digest this organic matter this is just if you're getting rid of garbage within you know in your home now also the refuse from harvest for example from corn can be used as a biodiesel or biofuels now households can work to separate non-biodegradables for example plastics and glass from their biodegradables so that they can be placed in recycling bins now of course combustion or burning is a quick method of eradicating waste but this results in air pollution carbon emissions and respiratory issues landfills generally involve the burial of waste materials so you have a large piece of land is excavated and the waste is very dear this would prevent accumulation of solid waste and breeding grounds for vectors because the underground are not exposed so what happens here is that decomposer bacteria they're gonna break down the material but they're gonna produce a large amount of significant amount of methane which is a powerful greenhouse gas but typically landfills have a catchment system or recovery system that could be installed to prevent the gases from actually seeping into the atmosphere as well as seen in the middle here so these landfills would also contain implementable liners to catch help for liquids from leaching into the soil is to be like battery fluid for example so what is the difference between a dump and a landfill well dumps are typically smaller than landfills landfills are pretty large dumps are usually open and they're not covered with soil on a daily basis so they typically produce a lot of bad odors or bad smells and they do not be too pests so these could be used as breeding ground sometimes for you know rats and flies dubs do not have a liner to catch any liquid leachate for example battery acid as i mentioned before produced by solid waste so a lot of this is going to enter these soils and if the dump is closed our water source is going to enter the water table um dumps do not have a treatment system or methane collections all those greenhouse gases are going into the atmosphere all right so let's look at controlling solid waste volumes so it has a growing population and a growing population means that there's greater amounts of waste being produced and less space to store that waste so we need to be able to control how much waste we actually produce we need to reduce the amount of solid waste that we have so how can we do that well we work with the three hours reuse reduce and recycle so reusing means to repurpose waste materials or finding other rules for them examples would be refilling water bottles using oil materials as plant pots reducing means simply constant consciously choosing biodegradable materials over non-biodegradable so choosing paper for example versus chosen plastic there's less and less buildup of waste over time so recycling materials means that you break their structure down and transform them into new materials so for example a glass and glass will be crushed or melted and then reformed or remolded into new glass products so the materials are crushed and then sorted by size and type magnets are going to separate any metals from non-metals so plastic sunglass as i said maybe remolded to manufacture new products and some paper may be pulped and repulsed and may be reused as well so what are some impacts on environmental issues on humans well let's start with flooding so flooding can occur due to the rise in sea levels due to climate change which we know is as a result of a lot of carbon emissions and pollution so if there's a lot of solid waste accumulating by waterways as well they could block the waterways and lead to rivers and sewage systems overflowing this now could lead to disease because if there's a lot of sewage systems overflowing on a lot of floods and a lot of garbage being piled up a lot of litter piles this may attract flies and rats which we know are vectors for cholera and leptospirosis if we have a lot of discarded tyres and cans and tins these may collect water and may act as mosquito breeding grounds food security is also going to get affected because if you have polluted soil and waterways this could lead to high toxicity in plant and animal food sources so for example when mercury is being dumped into oceans and fish was to absorb that mercury into their cells and then people eat that fish they get mercury poisoning as a result lastly now we have the economic impact of these issues flood damage and diseases result in high infrastructure and health costs for families and countries also highly polluted areas and countries are going to draw in less tourists as a result so we have a reduced revenue for that country so that's hsb good luck take care