what is going on it's medicosa's perfect status where medicine makes perfect sense this is the ultimate biology review video first of all let me be clear trying to review all of biology in less than 90 minutes is an insane task I'm going to go over the most important points in this video and we'll do this in the following order we will start by talking about the cell and what's in it of course there is the nucleus with DNA and the cytoplasm with the organelles then we'll talk about reproduction mitosis and meiosis after this embryogenesis and the fetal circulation followed by the nervous system somatic and autonomic central nervous system versus peripheral nervous system after that the endocrine system then the respiratory system followed by the cardiovascular system next the immune system digestive system homeostasis which includes kidney and skin musculoskeletal system bone and muscle and last will be genetics and evolution so let's go this video will be a very quick review if you want the detailed explanation go to my biology playlist first cell theory prokaryotes versus eukaryotes carry out is the nucleus so which one has the true nucleus the true nut eukaryotes it's a true nucleus Bound by a membrane and it's not just the nucleus even the organelles are bound by membranes eukaryotes have mitochondria they can make their own energy their DNA is protein bound but the prokaryotes have naked DNA in eukaryotes the DNA is linear anti-parallel in prokaryotes it is circular give me one example of prokaryotes bacteria how about eukaryotes we have many including mammals which will include humans what are the fundamental tenets of the cell theory number one all living things are composed of cells no kidding the cell is the basic functional unit of life cells are arise only from pre-existing cells this is the story of reproduction cells carry genetic information in the form of DNA here's your cell it has a nucleus it has cytoplasm if you lump them together this is called the protoplasm the cell is bound and surrounded by a plasma membrane or a cell membrane or a lipid by layer what kind of lipid phospholipid in this lovely cell membrane the head is hydrophilic it loves water so we put it on the outside hobo the tail well the tail is on the inside because it hates water it loves lipid but it hates water hydrophobic lipophilic and since there's water outside the cell and water inside the cell we will put the water loving hydrophilic heads towards water I.E on the outside and the inside and we will hide this hydrophobic tail away from water just bury it in the center what's the genetic material DNA which is organized in chromosomes you find chromosomes inside the nucleus how about the organelles like the mitochondria you'll find it in the cytoplasm the mitochondria will give you energy in form of ATP since the sperm needs lots and lots of energy it has lots and lots of mitochondria if you want to secrete a lot like the pancreas you will need lots of Golgi and endoplasmic reticulae don't you ever forget that red blood cells do not have organelles they do not have mitochondria therefore there is no TCA cycle or electron transport chain inside the red blood cell let's talk about these organelles the mitochondria is the PowerHouse lysosome is the soldier it destroys foreign Invaders how about the endosome the delivery guy endoplasmic reticulum comes in two shapes rough and smooth the rough is the translator we translate proteins for secretion we need rough endoplasmic and Golgi to work together how about the smooth this is the dough net for fat synthesis look how smooth this fat belly is Golgi is the sorter it modifies cellular products and directs them for delivery and it works in conjunction with the rough endoplasmic reticulum peroxisome from peroxide is the Gym trainer destroys fat is there a difference between cytosol and cytoplasm yes cytosol is just fluid with no organelles if you want to add the fluid cytosol to the organelles now we have cytoplasm if you want to add the cytoplasm two nucleus you get protoplasm here is your cell and your cell membrane inside we have protoplasm which is nucleus and cytoplasm the cytoplasm is organelles plus cytosol next the nucleus this is the control room of your body why because it has the DNA DNA carries your genes and don't forget the story of the nuclear pores inside the nuclear membrane these spores allow entry tree and exit from end to the nucleus the outer membrane of the nucleus is continuous with the rough endoplasmic reticulum this is how you make and then secrete proteins here's your DNA double helix wrap it around histones wrap it around wrap it around wrap book before you know it we have your chromosomes how many of these do you have in each somatic cell 46 chromosomes do you remember the nuclear pore yeah this is when mRNA tries to leave why does it want to leave because it will get translated later in the cytoplasm if you want to make another copy of DNA this is called the replication if you want to convert DNA into RNA this is called transcription if you want to translate the RNA into meaningful proteins this is called translation by the way you can download these notes and all of the notes in the entire biology series and medicosisperfectsnetis.com inside the nucleus we have the nucleolus for assembly of ribosome ribosome in the citizens of ribosomal RNA the rrna your average cell has only one nucleus red blood cells have none osteoclasts of Bones have many sometimes the nucleus is lobated or segmented such as your neutrophils which are white blood cells or leukocytes next the PowerHouse the mighty mitochondria provides you with energy this is on a good day but on a bad day it will kill yourself why is this because this cell is old malfunctioning starting to become harmful so it's Gotta Go Who's Gonna Let Her Go mitochondria what do you call it when the cell plans its own death apoptosis here's the structure of the mitochondria please pause and review when you keep pumping protons pumping protons pumping protons this is called electron transport chain what does it happen in the mitochondria when you keep pumping protons you are pumping them from the inside to the outside the crisp stay will increase the surface area for the electron transport chain the inner membrane contains all of the molecules and enzymes necessary for the electron transport chain but how about the inside Matrix it has the enzymes for the Krebs cycle or the chi-carboxylic acid cycle or citric acid cycle do not forget that your mitochondria has its own mitochondrial DNA you got your mitochondrial DNA from your mother only not from your father because your daddy's sperm left his tail outside he left the mitochondria outside red blood cells again no mitochondria but liver cell gazillion mitochondria next the Destroyer let's destroy foreign Invaders and let's destroy our own stuff that is senescent and no longer a value the lysosome is a destroyer because it contains Hydro enzymes that work in an acidic medium how come the lysosome is not killing me at all times because these hydrolytic digestive enzymes are protected and kept inside the lysosome thanks to the lysosomal membrane if you're a foreign Invader the lysosome will destroy you by endocytosis first and then destruction if you are coming from within I.E old senescent harmful particle then will destroy you by autophagy in the former process the lysosome needs help from the endosome for endocytosis but in the lateral process it needs help from the phagosome for phagocytosis here's the lysosome with the hydraulic enzymes engulf and Jew destroy there is a protein here that helps this physical separate from the membrane the name is called clathrin they love to ask about clathrin on the exam next the endoplasmic reticular is rough and smooth don't forget that it's continuous with the nuclear membrane the rough is the translator to translate proteins which were coded for in the DNA of the nucleus and then secrete them to the outside that's why its membrane is continuous with the nuclear membrane the smooth endoplasmic reticulum is the donut the rough has ribosomes rough ribosomes but the smooth no ribosomes function of the rough ER translation I.E protein synthesis IE to convert the RNA into proteins how about the function of the smooth curticulum fat synthesis and detoxification don't forget that the sarcoplasmic reticulum in your muscle is a modified smooth endoplasmic reticulum here's the rough versus smooth endoplasmic reticulum rough is to make proteins smooth is to make fat and to detoxify don't forget that your steroid hormones are made of fat and these include the sex hormones such as estrogen progesterone and androgens next is the sulta sort them and direct them for delivery the Golgi works with the endoplasmic reticulum the nucleus has the code and it makes RNA in a process known as transcription then this mRNA will leave the nucleus through the nuclear pore and will go to the cytoplasm where it will get translated in the rough endoplasmic reticulum I.E protein synthesis then we put those proteins in vesicles we give them to the sorta goldri and Golgi can secrete them to the outside world here's your nucleus mRNA will leave where continues with the rough endoplasmic reticulum translate that mRNA into proteins then give me those lovely vesicles and pure exocytosis from the intracellular fluid to the extracellular fluid so the Golgi can work in harmony with the rough endoplasmic reticulum moreover Golgi can work with endosome and lysosome we can do the exact opposite thing if this is a foreign Invader get it in by endocytosis and then lysosome and then two we will destroy you peroxisome the Gym trainer that destroys fat it drives me crazy when students make a mistake on the exam when it comes to peroxisome how can you forget that the name has the answer peroxisome from peroxide here is hydrogen peroxide why do you need this pair oxide for beta oxidation of fat lipid catabolism why do you need this hydrogen peroxide Mr peroxisome because it can help me kill foreign Invaders this is the story of the reactive oxygen species or free radicals and this is a lovely peroxide for you some diseases in medicine are peroxisomal diseases such as adrenal local dystrophy on your biology exam assume that all x-linked diseases are x-linked recessive unless they tell you otherwise if it's x-linked recessive it's going to be more common in boys next the cytoskeleton what's the most abundant thing in every cell in your body it's water what's the second most abundant proteins we have two types of proteins in the cell structural for the cytoskeleton and functional for enzymes pores channels pumps Etc your cytoskeleton is a protein Network who made it well ribosome again because it's a protein it helps the entire cell move cytokinesis it helps the cell divide during cell division mitosis or meiosis and it provides railroad tracks so that you can move your packages on the railroad the site the skeleton has gazillion other functions pause and review there are three types of cytoskeleton microfilament microtubules and intermediate filaments microfilaments actin how about microtubules alpha tubulin or beta tubulin and you find microtubules in cilia or flagella first microfilaments remember my actin you start with monomers then they become Polymers of G actin and then before you know it you have your actin filaments actin filaments have many functions including cell division these are your cleavage furrows that you studied in mitosis or meiosis for that matter next microtubules which have tubulin you have Alpha tubulin and beta tubulin microtubules can provide the backbone for many structures if you want to make a centriole easy I'll give you nine Triplets of microtubules and you will have a centriole but if you want a psyllium or if flagellum I'll give you nine doublets not Triplets of microtubules plus two additional ones don't forget the story of kinase scene and dining defect is seen in a disease known as cartagena's syndrome or Immortal cilia syndrome here is the Cilia as you know nine doublets of microtubules plus two extra ones cilia could be motile such as the one in your respiratory tract to get all the gunk out of your Airways or they could be immotile such as the special ones in the rods of the eye if I have Cartagena syndrome or Immortal Celia syndrome then the Cilia in my fallopian tube will not work and I can get ectopic pregnancy because I was unable to push the ovum from the fallopian tube to the uterine cavity because I did not have psyllium there are many genetic diseases that will give me respiratory problems including Cartagena syndrome where the problem is in the dying in arm of cilia and cystic fibrosis which is a cftr mutation the first diseases having no motile cilia the other disease is having very thick mucus because of a defect in the chloride Channel flagella structurally speaking very similar to cilia nine droplets of microtubules plus two single Central ones the sperm has a flagellum and H pylori bacteria has a flagellum too this is the nasty bacteria that lives in the stomach here is the structure of cilia or flagella we have nine doublets on the periphery and two single microtubules centrally what if I want to make a centriole not cilia or flagella then you go with triplets nine Triplets of microtubules remember that your cytoskeleton head microfilaments actin microtubules tubulin and intermediate filaments these intermediate filaments are different types depending on your tissue different tissues have different different types if you're talking about your missing camel cells your intermediate filament will be vimentin if you're talking about your epithelial cells keratin your neural cells neural filaments nuclear envelope lamine muscles Desmond neuroglial cells gfap next we'll talk about types of tissue including your epithelial tissue and your connective tissue as you know what's the building unit of your body the cell group of cells together tissue group of tissues together organ group of organs together make a system and the system will carry your body functions speaking of tissues you have four types of tissues epithelium connective muscle nerve epithelium I cover your surfaces I line your cavities doesn't that sound filthy I stand upon a basement membrane I am the parenchyma of your cells suppose we're talking about any gland in your body the gland will have a parenchyma the actual functioning cells such as the neurons in your brain the alveoli in your lungs and basically this will be mostly epithelial cells and the stroma which is just for support in our supports Outsource support Etc and the strum will be the connective tissue here are examples of epithelium in your body please pause and review and here are different types of epithelium based on the number of layers or based upon the shape of the epithelium next bringing people together the connective tissue when you talk about ligaments bones blood tendons fat lymph these are basically mostly connective tissue the actual function is undertaken by the parenchyma I.E epithelium but for the support you'll need your connective tissue connective tissue you speak about yourself I provide support I give a framework I make your stroma that supports you without me epithelium is nothing left with no support moreover I also make some collagen and elastin so I'm not that useless epithelium is here connective tissue is here if I flip you upside down metaphorically speaking will your organs fall out of place the answer is no why not connective tissue baby here are some examples of connective tissue we're talking bones cartilages fat cells or adipose cells tendons muscles some textbook even include blood and lymph as types of connective tissue next the cell cycle when you're resting your G zero and then you grow growth phase one and then you make DNA synthesis and then you grow again growth too and then mitosis or meiosis M phase somatic cells versus germ cells pause and review if I want to make another copy of my DNA this is called DNA replication which happens during the S phase of the cell cycle taking the DNA into RNA is transcription taking the RNA to proteins is translation with medicosis everything is a piece of cake where's the actual division happening in the M phase mitosis or meiosis that's why anything else is an interface g0 is for rest G1 is for growth because we're preparing for the S and the S phase you'll synthesize another copy of DNA hashtag replication then in the G2 you grow again and then in the M phase you have mitosis or meiosis Pro meta Ana Tello Pro Med anatello prophase metaphase anaphase telophase pause and review if the question asks you when does karyukinesis and cytokinesis take place the answer is M phase and here are some pearls for you pause and review cell types you have permanent cells or stable or labile cells labile cells are always dividing permanent cells do not divide stable cells do not divide under normal circumstances but under crazy circumstances they can divide such as your liver permanent do not divide such as your neurons labile always dividing such as sperm cells GI cells Your Hair Etc stable cells are only under certain conditions like the liver if my cells are dividing like crazy with no check this is cancer how does chemotherapy work they stop or arrest cell division what's the good news we're killing cancer cells what's the bad news we're also killing some of your cells especially those who divide very rapidly that's why with chemotherapy you get hair loss and diary cell cycle checkpoints to recognize the mutation or the error early on so that we can stop cell division otherwise we can get cancer we have three main checkpoints in the cell cycle the first one 1 is at the G1 or to be more precise it's between G1 and S so that if you discover an error you do not go to S recall that the p53 and the RB genes are tumor suppressor genes the second checkpoint is here between the G2 and the m so that you do not progress to the m phase with an error and the third checkpoint is in the M phase it's called the metaphase checkpoint and remember during the metaphase everything is aligned in the midline and we thank our mitotic spindle defects in any area of the cell cycle checkpoints can lead to diseases and here are some examples please pause and review more examples pause and review and some more if you have trouble with this please check the original video called cell cycle checkpoint in my biology playlist p53 is a tumor suppressor Gene what if my tumor suppress Gene is malfunctioning then you'll get what tumors which could be benign or could be malignant mitosis and meiosis here is a comparison between the two please pause and review in mitosis you start with 2N and you give me two identical cell each one is exactly identical to the parent cell also to n but in meiosis well it's called a reduction division because you start with 2N and you give me four cells each one is n H1 is not identical to the parent cell in fact each new Offspring is half the parent what are the phases Pro meta Ana Tello Pro before we're preparing meta everything is in the midline Anna separate me and then what's your Telos and purpose in life that's the last part during prophase there was condensation separation formation dissolution condensation of Chromatin into chromosome terms separation of the centriole pairs formation of the mitotic spindle we're getting ready and dissolution of the nuclear membrane next metaphase everything is M we are in the midline thanks to the mitotic spindle which is basically microtubule and you can draw the line in the sand here and you get a mirror image also an M we are aligned in the midline anaphase Separates Me Up split the centromere and separate the sister chromatid the kineto core is doing the pulling in telophase the mitotic spindle disappears we reform the nuclear membrane we form these cleavage furrows thank you microfilaments and then you separate the cell into two cells this is called cytokinesis meiosis there is meiosis one and there is meiosis II here is another comparison between mitosis and meiosis please pause and review you know the saying that meiosis system is almost identical to mitosis however there are some tiny differences next reproduction this is the anatomy of the female reproductive tract and here's the one for the male gonads in female we're talking about the ovary the gonad in males the testicle how about the gametes remember this is meiotic division in females the gametes the ovum in males the gametes the sperm here is spermatogenesis and this is oogenesis unlike spermatogenesis oogenesis gives you 1 over and three polar bodies contrary to popular belief fertilization is not when the sperm meets the ovum let's get technical it's when the sperm meets the secondary oocyte which is arrested in metaphase II fertilization is when the sperm meets the secondary oocyte which is arrested in metaphase II remember that oogenesis has two famous arrests Pro Phase 1 and metaphase 2 Pro Phase 1 and metaphase 2 Pro Phase 1 where the primary one with one oocyte is arrested waiting for the female to reach puberty how about the second arrest second arrest secondary oversight metaphase II everything here is two waiting for what for the sperm to go deep inside the oven XX female X Y male if you remember this is my hypothalamus here's my anterior pituitary which makes LH and FSH to influence the gonads and then the gonads will give you the male hormones or the female hormones this is the effect in the male GnRH from the hypothalamus will tell the anterior pituitary to make a legion FSH FSH influences the sertoli cell to feed the sperm and to help with aromatization but the LH is for elite Excel which is to make testosterone so what's the purpose of FSH in male from two I mean aromatization from the female hormone to the male hormone and then LH in males late Excel to make testosterone and the even more powerful dihydro testosterone but was the effect of FSH in females it's called the follicle stimulating hormone it stimulates the growth of the ovarian follicle about LH in females it's called luteinizing hormone it helps make the luteal body which will secrete progesterone until the placenta takes over here's the structure of the sperm remember that the nucleus is in the head the mitochondria is in the middle piece here's the process of spermatogenesis thank you sir Tolle cells we start with spermatogonia then primary spermatocyte secondary spermatocyte and then sperms let's make an ovum follicle stimulating hormone is going to simulate the follicle growth and then what and then the LH is gonna surge around day 14 and Pew rupture the follicle release the oven the oven will go to the uterus the rest of the follicle will become luteal body which secretes progesterone if fertilization happens progesterone and estrogen will remain high but if it did not happen progesterone will drop estrogen will drop and the uterine lining will drop hashtag Menses or menstrual bleeding pause and review these are the phases of the menstrual cycle we have proliferation phase thank you estrogen secretory phase thank you progesterone and some estrogen menstruation phase everything is dropping Like a Rock here's the function of FSH follicle LH The Surge and the rupture hashtag ovulation and then the estrogen female sex characteristics and then progesterone female secondary sex characteristics and it sustains the endometrium of the uterus and it raises the core body temperature in the second half of the cycle because progesterone is more abundant in the second half of the cycle the structure of the ovum please pause and review the steps of fertilization are 5. capacitation acrosoma reaction polyspermy block completion of meiosis II where the secondary oocyte was arrested in metaphase II and then you make a zygote capacitation is to increase the capacity thank you so much calcium next is the acrosoma reaction recognition happens release of hydrolytic enzymes so that the sperm can Pierce through the Zona pellucida next to avoid double and triple and quadruple fertilization there is polyspermy block to avoid polyploidy after this you complete meiosis II where the secondary oocyte was arrested in metaphase II now the secondary oocyte is ready to become an ovum after this zygote formation congratulations as I goat is one complete cell with 46 chromium chromosomes and then it will grow and grow embryo and then grow and grow fetus after birth you are a neonate within an infant after fertilization there is cleavage mitotic Division and then blastulation to make a blessed to cyst here's the blessed to assist we have an inner cell Mass which will become the embryo itself and an outer cell Mass trophoblast which will become the placenta fertilization then cleavage then blastulation after this implantation in the uterine wall then you have the bilateral embryo epiblast and hypoblast and the trilaminar embryo endodermesoderm ectoderm when you try to generate different layers this is called gastrulation please pause and review here is the by laminar embryo and the tri laminar embryo you need to memorize everything on this slide if you want to learn about new relation check out my video called neuralation in this biology series but please remember that the nervous system comes from the ectoderm the central nervous system I.E brain and spinal cord come from the neural tube the peripheral nervous system comes from the neural crest cells this is your spinal cord for example the spinal cord itself is central nervous system therefore neural tube but the spinal nerves are peripheral nervous system therefore neural crest cells this is your neural tube early on the anterior neuropore this will become your brain but the posterior nerve pore will become your spinal cord stem cells totipotent pluripotent multi-potent unipotent think of it like a tree branching and differentiating example these are pluripotent stem cells in the bone marrow which gives you the blood cells do you remember the bilometer embryo yeah the Inner Cell mass is an example of totipotent stem cell because it can give you any part of the embryo how about the mesoderm alone such as mesodermal cell in the mesenchyme of your bone marrow they are pluripotent ah for example the bone marrow can only give you blood cells not every single imaginable cell do adults have stem cells yes they do in fact this is how you regenerate the stem cells of your skin or the basal layer or the stratum basalis in the alveoli they are type 2 pneumocytes please remember that type 2 pneumocytes have two functions function number one they are the stem cells of your lungs function number two is to release surfactant which is anti-surface tension the stem cell of your bone marrow is the hematopoetic stem cell which is pluripotent and the cell that regenerates sperms is spermatogonia apoptosis versus necrosis please pause and review we have two types of cell regeneration there is complete and incomplete each time you undergo cell division and you pass through the cell cycle once you're getting older your telomeres are shortened do this many times and you are senescent old when your telomeres are shortening it means that you are aging but what if my telomeres do not shorten like ever is this a good thing shut up it's a horrible thing it increases your risk of cancer this slide is historic that's why I keep repeating it pause and review next let's talk about the fetal circulation what's the purpose of the placenta give oxygen and nutrients from Mommy to baby and give CO2 and waste from baby to Mommy this is the difference between the adult circulation and the embryological circulation here is how the placenta looks this is the maternal surface and this is the fetal surface fetal hemoglobin or hemoglobin F will shift the oxygen dissociation curve to the left and with left shift the tissue is Left Behind because oxygen will remain on the hemoglobin and will not go to tissue do you remember the story of the shifters of the oxygen hemoglobin dissociation curve with left shift the tissue is Left Behind whose tissue mommy's tissue is Left Behind you know why because this oxygen is going to go to the hemoglobin F because hemoglobin F loves the oxygen so much I.E more binding but less dissociation and this is how the baby takes all the oxygen that it can from Mommy smoking alcohol folate deficiency finito and Warfarin thalidomide all of these are teratogens which can increase risk of congenital anomalies and mutations especially during the first trimester of pregnancy because during the first trimester the cells are dividing very rapidly that's why they are the most vulnerable this is the adult circulation we go from left ventricle and then all over your body back to right atrium right ventricle then give me to the lungs and then gas exchange back to the left atrium pause and review but the fetal circulation is different you are going to get the oxygenated blood from the mother thank you umbilical vein and then you bypass the liver thank you doctor's vinosis we are in the inferior vena cava you go to the right atrium and thanks to the patent for Raymond o'valley you go to the left side oxygenated blood will go all over your body the deoxygenated blood comes back through the severe and fear vena cava this deoxygenated blood was trying to go to the lung but because the lungs are closed with very high resistant the pulmonary artery said you know what screw it I'm not going to the lungs I'm gonna bypass the lung thank you doctors arteriosus and I will dish my blood onto the aorta what's the fate of these embryological structure after birth doctor's vinosis will become ligamentum vinosum foramen ovale will close and become the fossa of Ellis ductus arteriosus will become a ligamentum arteriosum the nerves system central and peripheral brain and spinal cord peripheral cranial nerves spinal nerves in your spinal cord the gray matters on the inside white matter is on the outside but in the brain is the opposite remember that myelin appears white therefore if I am unmyelinated I appear gray pause and review somatic is something that you can control voluntary autonomic is something that you cannot involuntary the autonomic nervous system could be sympathetic or parasympathetic or enteric nervous system in your gut a collection of cell bodies in the CNS is a nucleus a collection of cell bodies and the pns is a ganglion a collection of axons in the CNS is attract in the pns it's called the nerve what's the structural unit of the nervous system neuron how about the functional unit reflex arc who makes myelin well in the CNS it's the oligodendrocytes but in the pns it is Schwann well myelin increased conduction via saltatory movement type A and B nerve fibers are myelinated by type c fibers are unmyelinated all your neurons have enrollment sheath regardless why do we need action potential because the action potential is life the nerve impulse in your body is unidirectional it always go it always goes in the direction from the Soma towards the axon terminalis the beginning part of the axon is the axon HELOC and this is the structure of the neuron please pause and review this is the structure of your nerve endonorium on the inside then perineurium and everything is covered with epinurium neurotropins are not the nerve impulse nerve impulses unidirectional it goes down there but neurotropins can go by retrograde nasal bodies are a very important exam question this is rough endoplasmic reticulum and and they are found in the neurons but not in the axon please pause and review and this is why myelin is awesome what is the pilot of the nervous system the neuron how about the co-pilot the co-neurons I.E neuroglial cells the first two will make myelin astrocyte is for the blood brain barrier micro glare is the macrophage of your nervous system ependymal cells make the CSF do you remember my intermediate filaments yeah in the neurons they are the neurofilaments but in the glial cells they are the gfap pause and review if I lose my myelin in the CNS this is multiple sclerosis if I lose the myelin and the pns this is Guillain-Barre more about the action potential during resting state potassium is leaving and when the positive leaves the inside becomes more negative that's why it's resting which means inactive but when sodium decides to enter sodium is positive when positive comes comes in the inside becomes more positive hashtag activation hashtag depolarization during rest resting membrane potential upon stimulation action potential here's the action potential during rest potassium is leaving that's why the inside is negative and then upon depolarization sodium enters the inside becomes more positive and we are very active then we go back to being inactive this is called repolarization and if you take it too far hyperpolarization because potassium is leaving and the inside is becoming more negative again who's responsible for the resting membrane State selective permeability I.E more potassium leaves then sodium entering when the positive leaves the inside becomes more negative the second thing responsible for the resting membrane potential is the sodium potassium 80 base pump here's the action potential please pause and review depolarization is sodium entry repolarization is potassium efflux and let's put everything together when your neurone is sick and tired of being sick and tired it's called the refractory period which means I cannot get excited again there is the absolute refractory period with very high standards I am not going to be excited again no matter what but relative refractor appeared is like forgive me is a two dollar hooker I'm not gonna react I'm not gonna be excited but if you give me super threshold too much money I might give you an action potential these are the types of fibers that we have cholinergic versus adrenergic and the receptor on each pause and review how do I get the Target to get excited first sodium entry this is depolarization and then action potential propagates in the presynaptic neuron calcium entry calcium ruptures the vesicle and then pure exocytosis acetylcholine is going to bind to the acetylcholine receptor assuming that this is a cholinergic fiber and then look at that receptor here if this is the skeletal muscle nicotinic sub M and then the muscle will have its own action potential how does the muscle contract well well well the end plate potential will propagate through the T tubules of the muscle and then calcium will be released calcium with the c minus troponin C and then myosin binds actin J contraction the comparison between somatic and autonomic is very important so please pause and review if this is a ganglion the fiber before it is preganglionic the fiber after is post-ganglionic before it it's type B fiber that's why preganglionic are myelinated but in the post-ganglionic we're talking C fibers unmyelinated only autonomic fibers have ganglia the somatic system does not this is the sympathetic nervous system thoracolumbar and this is the parasympathetic system which is craniosacral what do you mean by cranial I mean 1973 Korean nerve 3 cranial nerve 7 9 and 10 are the only Korean nerves that are parasympathetic this is what happens when you are in fight flight mode pause and review and this is parasympathetic rest and digest read eat and take a dump urination defecation sympathetic nervous system when you're running from a tiger you need to see far ahead so far Vision because my lens is flat however if you are parasympathetic land you want to read a book rest and digest it read and take a dump when you are reading you need your lens to be spherical accommodation the sympathetic nervous system is gonna dilate the pupil thank you all for one but the parasympathetic will constrict the pupil thank you M3 receptor here is the effect of sympathetic and parasympathetic on the male copulatory organ parasympathetic will Point sympathetic will shoot and Shrink on the urinary bladder sympathetic will relax the wall all constrict this sphincter but parasympathetic will contract the wall relax the sphincter which sphincter the internal because it's involuntary hashtag autonomic contrast that with the external which is voluntary hashtag somatic compare and contrast between sympathetic and parasympathetic the parasympathetic is always cholinergic however the sympathetic starts cholinergic in the preganglionic but the post-ganglionic is adrenergic the endocrine system hypothalamus anterior pituitary three glands that listen three glands that do not care the three that lessen our thyroid adrenal cortex gonads the thyroid listens to the pituitaries TSH adrenal cortex will obey the pituitaries ACTH the gonads will listen to FSH and LH all of these hormones are made and secreted by the antipituitary however ADH and oxytocin are made by the hypothalamus and then released by the posterior pituitary the effect of different hormones on the female breast estrogen increases the size and makes some ducts progesterone makes the alveoli or the asini prolactin is Gonna Fill them with milk oxytocin is going to push the milk out if this was oxytocin how about ADH then this is for reabsorption of free water in the collecting duct of your kidney ADH is called vasopressin with the V therefore the name of the receptor is V2 and the channel is called aquaporin II channel three to choose choose what water only without sodium here is the pituitary again anterior pituitary versus posterior pituitary pause and review insulin versus everybody else insulin is anabolic on everything all the other hormones are catabolic on everything but growth hormone is kind of in the metal from insulin it borrowed the first thing which is protein anabolic but from the other hormones it borrowed number two and three it is glycogen catabolic and fat catabolic here are the actions of growth hormone please pause and review thyroid gland let's make thyroid hormone don't forget that we need iodine what's the key enzyme thyroperoxidase who's gonna bind tyrosine thyroglobin here are the actions of thyroid hormone remember it's the stove of your body it increases and boosts metabolism that's why if you have too much thyroid hormone everything is working really fast but if we have hypothyroidism I am so lazy behind the thyroid gland we have two pairs of glands known as parathyroid glands to make that parathyroid hormone the parathyroid hormone is procalcium it increases calcium in the blood however it's also a fat fate trashing hormone it decreases serum phosphate calcitonin hates everybody so lowers your calcium and phosphate vitamin D3 has a brain I can increase serum calcium just like pth however I noticed that both of them are trashing phosphate which is dangerous because you need adenosine Tri phosphate which is ATP so I'm gonna raise serum phosphate adrenal cortex versus Adrenal medulla the cortex will make aldosterone cortisol adrenal androgens the medulla will make catecholamines including dopamine norepinephrine and epinephrine what's the function of aldosterone made by the zoneglomerulosa it reabsorbs two things and dumps two things into the urine glucocorticoids want to boost glucose via gluconeogenesis adrenal androgens are androgens don't you ever forget the renin Angiotensin aldosterone cyst the kidney he makes renin which converts Angiotensin Ogen to engine 1 then Ace from the lung the Angiotensin converting enzyme is going to convert Angiotensin 1 to angiogensin 2 which has two functions Function One constrict vessels function 2 make aldosterone from the zoneglomerulosa of the adrenal gland which will reabsorb two things back to the blood and dump two things down the toilet here is the Adrenal medulla and the catecholamines remember the song phenylalanine tyrosine doped dopamine nor epinephrine epinephrine the adrenal cortex came from the mesoderm but the medulla belongs to the ectoderm because it's part of the peripheral nervous system we treat her like a ganglion adrenal cortex versus medulla pause and review pancreas time exocrine versus endocrine exocrines to make the enzymes endocrines to make the hormones what kind of hormones insulin Island from the beta cells and glucagon from the alpha cells insulin is anabolic it builds up protein from amino acid it builds up glycogen from glucose it builds up triglycerides from free fatty acid but glucagon is a destroyer that's why it goes in the opposite direction that's why when you're feeding it's time to build up you need insulin but when you're fasting it's time to break down and get some energy you need glucagon Alpha sulfur glucagon beta cell for insulin and Delta cell is the doofus somatostatin because it inhibits everything do you remember reproduction pause and review do you remember this pause and review more hints about endocrine pineal glands make melatonin important for circadian rhythm the kidney makes IPO which goes to the bone marrow to boost red blood cell production when the heart gets stretched out because I have volume overload or heart failure I secrete a and pay or BNP net rheoretic peptide natural heretic you will lose the natrium sodium and water in the urine it's time to breathe here's the anatomy of the respiratory system please remember that you have a conducting Zone and a respiratory zone here are the functions of each part of your respiratory tract here is a comparison between conducting Zone and respiratory zone your pleura surrounds your lungs it's filled with a thin layer of fluid it has a visceral layer and a parietal layer if air pressure is higher in California than Arizona then wind will blow from California to Arizona from high pressure to low pressure reveal boil law which means volume and pressure hate each other if one is going up the other is going down provide that temperature remains constant when I'm trying to breathe in I expand my chest volume goes up pressure goes down I have a more negative pressure inside therefore I'm gonna suck air in because negative pressures pull in stuff the exact opposite happens during expiration you breathe air in from the atmosphere it goes to your lungs then it goes to your arterial blood in the beginning free and dissolved then it jumps on the hemoglobin the cell will use it and then you get the CO2 back to the hemoglobin and the lung will breathe it out for you surface tension is dangerous it wants your lungs to collapse and recoil but thankfully you have a surfactant made by type 2 pneumocytes and this surfactant is anti-surface tension so that you can breathe here are the pulmonary function tests please pause and review lung volumes are here lung capacities are here what's an acid anything that gives you protons the more proton once you have the higher your hydrogen ion concentration and the lower your pH in your body your metabolism secretes acids and carbon dioxide which is technically an acid because it combines with water and give you carbonic acid who will get rid of this volatile acid the lungs who is going to get rid of these non-volatile or fixed acids the kidneys if you metabolize more you will end up with more acids if you breathe more hyperventilation will lower your carbon dioxide in the blood conversely hypoventilation will raise the carbon dioxide in your blood please pause and review loose chetal yields principle if your bicarbonate goes up and pH goes up this is called metabolic alkalosis if bicarbonate goes down and pH goes down this is called metabolic acidosis if carbon dioxide goes up pH will go down respiratory acidosis if carbon dioxide goes down and pH goes up this is respiratory alkalosis between the artery and the vein which one is more acidic of course the vein is more acidic because carbon dioxide is dumped from the cell onto the vein and carbon dioxide is a freaking acid when you go up on top of a mountain there is a lower pressure therefore lower pao2 but the air itself is still 21 percent oxygen so fio2 did not change then why do I have less oxygen in my alveoli because the pressure of the atmospheric air which includes oxygen went down anytime you have low oxygen your body will respond by making more red blood cells thank you kidney for secreting erythropoietin and can also make no blood vessels when you're exercising or when you go on top of the mountain what's going to happen shift to the right how about the opposite shift to the left any time I exercise my right arm the right arm will have more metabolism and therefore more carbon dioxide more acidity because carbon dioxide is an acid I'm raising the temperature of my right arm and increasing glycolysis and therefore 2-3 BPG when all of them go up I will shift to the right with the right shift there is giving of the oxygen to the tissue which means oxygen is leaving the hemoglobin and going to the tissue the exact opposite happens with left shift with left shift the tissue is Left Behind because oxygen is remaining on the hemoglobin and away from the tissue here's the effect of high altitude on your body please pause and review when I go on top of the mountain I get hypoxia and my body will respond I shifted my oxygen dissociation curve to the right and the tissue is happy with more oxygen since there is less oxygen pressure upstairs I will breathe more therefore carbon dioxide in my blood will decrease is because of the hyperventilation and the pH will go up we call this respiratory alkalosis cardiotime here is the adult circulation here are the four valves in the heart all of them are tricuspid IE with three cusps except the mitral which only has two cusps do veins have valves yes how about arteries no please remember that the cardiac muscles are striated involuntary uninocreated and branching with lots and lots of Gap Junction the Gap Junction is very important for your heart because it allows the entire heart to contract as a One Singular unit a sensation here's the SA node and the AV node that's why your heart is automatic sympathetic and parasympathetic are not initiators they are just Regulators what causes the first hard sound the closure of the mitral and tricuspid valves together how about the second hard sound the closure of the aortic and pulmonic valves together between the first heart sound and the second hard sound it's called systole because your ventricles are Contracting between the second heart cell and the following first heart sound is called diastole because your ventricles are relaxing cardiac output is heart rate times the stroke volume the productivity of your heart is based on how fast times how strong your heart is beating the pressure inside big vessels is 120 during systole and 80 during diasty but in the left ventricle it's 120 during surgery same but almost zero during diastere then how come the aorta was 80 not zero during diastere it's thanks to clamping down on that blood and this is why you get the dichrotic notch that's how the Iota prevented your pressure from dropping to zero during diastere unlike the left vent let's talk about the volume of blood in the left ventricle when The ventricle is squeezing itself and push the blood out less blood will be left in The ventricle you go down like but when The ventricle is relaxing and receiving blood the volume of blood in the left ventricle will go up put everything together in one shot and you get the Lovely cardiac cycle you need to understand everything here let's talk about capillaries there is arterial end and venous end each vessel is made of Tunica intimate Tunica Media Tunica adventitia contrast and compare among arteries veins and capillaries please these are the different types of arteries different types of veins and different types of capillaries in your body some Pro tip if you vasodilate you'll increase the radius and the diameter of the vessel therefore the resistance goes down the afterload goes down the blood pressure goes down remember the meta arterial plays and remember that we have pushing forces hydrostatic pressure thank you blood volume and we have pooling forces uncortic pressure thank you albumin which is a plasma protein if I want to feed my cell I.E I want the blood to go this way from the capillary to the cell therefore the favoring forces should exceed the opposing forces what are your favoring forces here hydrostatic pressure in the capillary and oncotic pressure in the interstitial fluid which are your opposing forces uncortic pressure in the capillary because it pulls this way and hydrostatic pressure in the interstitium and then you do it this way favoring forces minus opposing forces if the end result is a positive number it means that you are pushing fluid out of the capillary into the cell let's talk about blood cells and plasma as you know your blood is made of plasma and cells these cells are red blood cells while the cells and platelets but the plasma is water and proteins could be albumin proteins or globin proteins which one is responsible for the oncotic pressure albumin which one will give your coagulation factors and your antibodies globulin these are your blood cells please pause and review red blood cells are circular by concave non-nucleated they do not have a mitochondria therefore there is no Krebs cycle no electron transport chain in the red blood cell the only source of energy for the red blood cell is glycolysis basically next white blood cells why do we have neutrophils they fight bacteria and they are the cells of acute inflammation why lymphocytes they fight viruses and fungi and they are the cells of chronic inflammation how about monocytes they become macrophages which are phagocytic cells they eat up stuff eosinophils fight parasites and Allergy remember eosinophils ew how about basophils they release histamine platelets or the thrombocytes they help you make a clot to stop the bleeding how do you stop the bleeding first you vasoconstrict then the platelets will help you and and primary hemostasis then the coagulation factors I.E beta globulins will help you this is secondary hemostasis here is primary hemostasis thank you platelets here is secondary hemostasis thank you coagulation factors next on the surface of your red blood cell we have the antigen system and we have the RH antigen system you only have two antigens by the way A and B well how about O then o means zero oh you have neither a nor B that's why we call you o please pause and review don't forget the blood typing and blood matching which we have discussed before next immunity you have innate immunity you're born with it and adaptive immunity which you acquire the innate immunity is non-specific at all cells of the innate immunity are many don't forget the macrophages the microphages mast cells and basophils dendritic cells and the natural killer cells but when it comes to the adaptive immunity we have B lymphocytes humoral or TL lymphocytes cellular here are the B lymphocytes making plasma cells which will secrete antibodies you have IGM IGA IG ige and IGG all of them are gamma globulins each of these antibodies has heavy chains and light chains when something invades your body you take a pace called an antigen then the antigen presenting cell will present that antigen to the lymphocyte the lymphocytes can destroy that microbe if it's a bed lymphocyte it will grow and become plasma cells to make antibodies and more importantly you will develop memory so that the second exposure is faster and stronger here is a comparison between hemoral immunity and cell-mediated Immunity here are your lymph nodes remember there is the police academy for the beat lymphocytes it's the bone marrow for the T lymphocytes it's the thymus then we have police officers these are the lymphocy sides then we have police stations these are the lymphatic organs here is the lymph node it has a cortex it has a medulla and in between it has a pair of Cortex the cortex is for the B lymphocytes pericortex is for the tlm4 sides and then the medulla with the medullary sinus is for plasma cells and macrophages compare and contrast and again and one more time next digestion digestion is to break down the macro into the micro and then you are able to absorb the micro and send it to blood the liver will metabolize it if you could not digest it and absorb it you will end up pooping it your gut has a wall and a lumen the wall is made of mucosa submucosa musculosis Eros digestion could be mechanical by motility or chemical bise secretions motility is by the my enteric plexus secretion is with the submucosal plexus you have lots of glands in the DI AI part of them are just part of the elementary Canal others are outside or accessory glands here's the anatomy of the digestive system now let's talk about the function from head to toe in the mouth there is mechanical called mastication and chemical digestion called salivation the enzyme is amylase the function is carbohydrate digest next send the food to the pharynx and then the esophagus and then the stomach the stomach has mechanical which is mosility and chemical which is secretion you need to memorize every cell in the stomach and what it makes GI hormones include gastrin which is made by the G cell the only hormone that is pro stomach increases motility and secretion of the stomach secretin is secreted by the S cells in the upper part of small intestine secretion tells the pancreatic ducts to make lots of water and bicarb to neutralize the acidity cck cholecystokinin pancreasion is called cholest too kind because it squeezes the gallbladder it's called pancreas iron because it increases the release of pancreatic digestive enzymes from the s in our cells somatostatin is the doofus from the Delta cell why doofus because it inhibits everything it even inhibits its own secretion in order for you to digest and absorb the fat and the fat soluble vitamin you need three organs to be healthy liver and biliary system pancreas and the gut after you digest what do you do you absorb what if you could not absorb the new excrete if you happen to be water soluble you will go the blood route but if you are fat soluble you'll go through the lymph around and this is true for vitamins if you are water soluble vitamin blood route if you are lipid soluble vitamin lymph route here is all of digestion in one slide here is how we digest carbohydrates here is how we digest proteins and here's how we digest fat next kidney please review your anatomy and the physiology of the kidney after the renal artery branches and branches and branches even more you get the afferent arterial which becomes the glomerular capillary tuft and then you push fluid this way called filtration if you cannot push it it's going to end up in the efferent arterial which will become peritubular capillaries here is the afferent here's the glomerular capillary tuft here is the afferent the efferent will become peritibular capillaries now let's talk about the nephron here's the Bowman's capsule proximal tubule Loop of henle distilled collecting ducts when something leaves that filtration fluid in the nephron and goes to peritibular capillary this is called reabsorption the app is called secretion anything that's going to end up in the urine is called excretion how do we move based on what Starling forces hydrostatic and oncotic hydrostatic pushes on cutic pulls hydrostatic depends on and the volume of fluid but uncortic depends on albumin if you want filtration from the glomerular capillary to the nephron the favoring forces should exceed the opposing forces but if you want reabsorption it's going to be the opposite if you want secretion it's going to go from here to there next the skin it has many functions the epidermis of your skin came from the ectoderm but the dermis is derived from the mesoderm here are the different layers of the epidermis please remember that the stratum bezeli is the stem cell for regeneration the dermis is the connective tissue underneath the skin is important for thermoregulation please pause and review bones and muscles you have three types of muscles right we have compared among them before correct when it comes to smooth muscles just say no here's the structure of your muscles from the inside to the outside endomysium perimysium epimysium just like the nerve in dunurium perineurium epineurium its muscle is made of muscle fibers each fiber is made of myofibrilles H5 bryl is made of myofilaments which include the thin actin and the thick myosin please pause and review please review the difference between the a band and the eye band I band has only actin a band has myosin and actin the H Zone has only myosin upon contraction what happens your eye band will shorten your H Zone will shorten but a band does not change how about the length of the entire muscle it decreases contraction is sliding of myosin and actin myosin is going to extend those cross Bridges and pull actin towards the midline skeletal muscles have nicotinic receptors smooth muscles have musculine or adrenergic receptors how about cardiac muscles similar to smooth muscles this is the neuromuscular transmission again please pause and review when the action potential reaches the muscle it will Traverse the muscle via T tubule and then calcium is released from the jail which is the terminal cistern of the sarcoplasmic reticulum and then calcium Will bindroponin C and then tropomyosin is removed the active site is exposed myosin will pull actin towards the midline hashtag contraction which require lots of ATP let's compare between type 1 muscle fibers and type 2 fibers muscle contraction requires lots of ATP which is in the myosin head because it has 80 phase activity metabolism of the muscle first you start by using the phosphogen system creatinine phosphate ADP will become ATP and you have some energy thank you creatine kinase after this you need to rely on your glycolysis to give you the famous two ATP molecules after this you need your oxidative phosphorylation and electron transport chain I.E TCA cycle and ATC which gives you a net of 38 ATP molecules after exercise the muscle and the lung made a deal hey hey hey I am the muscle I need 500 ml to complete that Marathon but I can only get 400 right now okay here is a deal you can give me the 400 right now but then after I finish exercise you owe me a hundred bet that's the oxygen debt and that's why you're hyperventilating even after you finish the marathon while you're doing this the lung is paying back her debt why is this 100 ml of oxygen crucial for reformation of ATP and creatine phosphate removal of lactic acid and refilling the myoglobin with oxygen next bone and Carthage we have exoskeleton and endoskeleton if you're a human being you only have an endoskeleton your endoskeleton is either axial in the midline OR appendicular in the extremities bone we have the head we have the shaft we have epiphysis we have diaphysis and we have metaphysis in between your bone could be compact especially on the outside or spongy especially in the middle near the middle near the bone marrow osteoblasts will build up your bone but osteoclasts will cut down bone your bone is basically Matrix thank you collagen and minerals thank you calcium and phosphate what kind of collagen is in Bones Bones have type one collagen but type 2 collagen is in cartoonage please review your hiversion system and here is a distinction between bone and cartilage type 1 versus type 2 vascular versus a vascular when two bones are ready to meet each other it's a joint and you have some lovely fluid for lubrication and there are three types of joints in your body coming up next genetics this is the big picture of genetics please review the difference between penetrance and expressivity which could be variable or constant understand and memorize your definitions Master dominant versus recessive homozygous versus heterozygous and here are the laws of Gregor Mendel the first law of segregation thank you anaphase one and the Second Law of Independent Assortment thanks prophase one this is prophase one the tit red and the crossing over which explains the second law of Mendel all the alleles in a given population of people is called the gene pool can we have mutations of course we can have mutations affecting the nucleotide or a mutation affecting the entire chromosome please pause and review do not forget that Miss sense is sickle cell disease nonsense will give you a stop codon stop the nonsense you need to draw tons of Punnett squares before your exam this is the result when you have one autosomal dominant parent and another autosama recessive parent and both are homozygous this is the result let's take the first generation and marry them with another person from the first generation and what do you get right now you get a different ratio as you see and this was called the monohybrid cross because we're talking about just one characteristic which is their color but what if we're talking about two things their color and their height then it's going to be the dihybrid cross with a different rent ratio please pause and review this is the result of sex-linked crosses we can map genes and chromosomes and get the recombination frequency which is proportional to the distance between two genes on a freaking chromosome using this Theta or a combination frequency you can deduce the order of genes on a chromosome and we talked about this before Hardy Weinberg equation it's not hard you just need to memorize two equations more importantly you need to understand what each letter refer to for example the P alone is the frequency of the dominant Elite in a population but the P Squared is talking about an individual in that population P alone is the tall allele P Squared is a tall individual and here is an example that we did before just by giving you the first number which is 70 percent you can deduce all of the rest please pause and review and do it yourself Evolution Basics do not confuse natural selection with Evolution they are not identical in fact natural selection is a mechanism for evolution there is the old Theory and the modified modern synthesis theory we have different modes of natural selection could be stabilizing directional or disruptive when it comes to reproductive isolation it could be pre-zygotic which prevents the zygote from forming in the first place or pose the Exotic which allows as I go to be formed however it's gonna be non-viable or sterile an exam question will ask you about the mule the mule is an example of hybrid sterility which is a post zygotic isolation pattern of evolution or many we have Divergent parallel and convergent we did it you can download my notes at miracostessperfectsnellis.com they have extra points than we discussed in this video and you can download my surgery high yield scores if you are interested I also have many other pharmacology courses the biology playlist is complete and I've started talking about biochemistry in a separate playlist called biochemistry for the MCAT thank you for watching please subscribe hit the bell and click on the join button you can support me here or here go to my website download my courses be safe stay happy study hard this is miracosta's perfect snail is where medicine makes perfect sense