Introduction to Anatomy and Physiology

Anatomy and Physiology 1, Chapter 1. So in order to take Anatomy and Physiology, we first need to understand what it is that we are studying. What does anatomy mean and what does physiology mean? mean. So anatomy describes the structures of the body, what they're made of, where we find them, and what's associated with them, what connects to them. The easiest way to boil this down is to just say that anatomy is what things look like. So if you're studying the structure of the heart and the blood vessels that meet with the heart, you would be looking at the anatomy. Physiology is the study of the functions of those anatomical structures, and the easiest way to describe physiology would just be how things work. So in order to really understand the human body well, we need to put them together. You could be an anatomy expert and know nothing about how those organs work. So by knowing the physiology, we can tie all of that together and get a very deep understanding of that particular organ or system. Anatomy can be divided up into subcategories. Gross anatomy also... known as macroscopic, macro meaning large, or visible without magnification, so we'd be able to easily see this without using a microscope or any other type of magnification. First, we have surface anatomy, and this is when we are literally studying the surface of something, looking at just the exterior or outside parts of the body without any dissection. Occasional anatomy is is looking at a specific body area. For example, if you wanted to study the musculature of the head and neck specifically, that would be a region. Sectional anatomy is when we take cross sections through the body and study those cross sections like is often done in a CT scan or MRI. Systemic anatomy is the study of the individual organ systems. So So looking at the cardiovascular system specifically, for example. Clinical anatomy is the medical specialty subcategory, like when we look at tissues in pathology, for example. Developmental anatomy is the study from conception to adulthood. So this would be including embryology. So studying embryology and then fetal development. and so on. Microscopic anatomy is when we do have to use magnification to study the anatomy. So this would be things like cells and molecules. Cytology is the study of cells and histology is the study of tissues. We will review this a little more later but tissues are collections of cells that are working together to perform very specific functions. So histology would be the study of those tissues. Physiology, or how things work, can also be divided up. Cell physiology is the study of the function of the individual cells. We're going to look a little more into that in chapter three. Organ physiology is looking at the function of the whole organ. Systemic physiology is looking at the function of the whole organ system. We're going to be doing some of both of those in addition to cell physiology. Pathological physiology is the effects of disease on the specific organs we're talking about. So to start at the beginning and really get a good understanding of the cell and then the tissue and then the organ and organ system, we need to remember what the hierarchy of life is or the levels of organization. And this is something that is often talked about in general biology. So we start at the bottom where we find the atoms. And atoms are the smallest, most stable units of matter. And when we combine atoms with... specific types of bonds, we get molecules. These are groups of atoms. Examples would be things like proteins. Complex molecules can form larger structures called organelles and these are the tiny parts that are inside of the cell that have very specific functions. You might remember from biology the mitochondria, the nucleus, the rough and smooth endoplasmic reticulum, for example. If we group up the organelles, including the cell membrane, we get the cell, which is the smallest living unit in the human body. If we group similar cells together that work as a team, we get the tissue level. If we group tissues together and these tissues are similar, then we get the tissue level. organs. If we put the organs accessories or organs that work with it together we get the organ system. Humans have 11 organ systems which we will eventually cover all of and if we combine all 11 organ systems together we get the whole organism. So to review that through picture we have atoms atoms combine to form molecules like this complex protein. Molecules can combine to form organelles. We talked about things again like the mitochondria, the rough and smooth endoplasmic reticulum, and then we can group the organelles together with the membrane to get the whole cell like this heart muscle cell for example. If we group other heart muscle cells with this one, we get cardiac or heart muscle tissue. And all the tissues that are similar, that work together combined, will make the heart. And if we put in the blood vessels, like the arteries, veins, and capillaries, we get the entire cardiovascular system. And if we put all the other systems in, then we get the entire cardiovascular system. then we get to the organism level or the top. So here are part of the organ systems and in chapter one all we really do is just go over a very light overview of the main organs and the main functions. Nothing too deep yet. We'll individually take those systems later and go over them in great detail. So starting at first with the integumentary system. fancy for skin and this is going to include the skin and anything that grows out of the skin so the hair sweat glands nails all grow out of the skin the function of your skin is to protect you number one against anything outside environmental hazards bacteria it's also going to help regulate your body temperature you've got fat in your skin that helps to keep you warm and you And you also sweat when you get hot and this is going to help you to cool down. Your skin also contains lots of sensory nerves so we can feel through our skin. Next we have the skeletal system and the skeletal system is going to include bones, cartilage, ligaments and also bone marrow. The bones are going to support and protect your body, give you structure and also when we talk about protection. specifically mean protecting vital organs like the skull protects the brain and the ribcage and sternum are going to protect the heart and lungs. We also store calcium and other minerals in our skeleton and our bone marrow is responsible for forming blood cells. Next we have the muscular system which is made up of skeletal muscles and tendons. Muscle Muscles are going to provide movement and they also will support soft areas as well. By moving our muscles we generate body heat and that helps to keep us warm. The nervous system includes brain, spinal cord, nerves, and sense organs like the eyes. The nervous system is important because its job is going to be to direct responses to stimuli that your brain is going to be able to control. nervous system perceives. So if a bright light shines in your eye or you hear a noise behind you, your nervous system will be able to interpret what you're seeing or hearing or feeling. It also gives you conscious awareness and allows you to understand your surroundings, what's going on around you, and coordinate activities of other organ systems. The endocrine system is going to include some major glands like the pituitary and thyroid gland, pancreas, adrenal, gonads, and any other tissue that makes hormones, which is primarily what the endocrine system is responsible for. These hormones are chemical messengers that are going to direct long-term changes in your body. These hormones can adjust your metabolism and also help with structural and functional development. Cardiovascular system includes the heart, blood, and blood vessels. It's responsible for distributing blood around the body and this is important because the blood is going to contain dissolved gases like oxygen and carbon dioxide and in addition to that we're going to use the blood to distribute nutrients throughout the body to the cells. Your blood flowing also helps to distribute your body heat to help maintain your core body temperature. Next we have the lymphatic system and the lymphatic system is responsible for immunity. So this is going to include the spleen, thymus, lymphatic vessels, which remind me a bit of blood vessels. run all along the body and also your lymph nodes and tonsils. Since this is considered your immune system it's going to defend against infection and disease and also help to return tissue fluid to the bloodstream. The respiratory system is going to include your nasal cavities, sinuses, larynx, trachea, bronchi, lungs, and alveoli. Primarily the respiratory system is responsible for your breathing. So we're going to bring air into the lungs where we can get oxygen from that air and we're going to deliver CO2. from the body to the lungs so that we're able to exhale it. We can also talk through our respiratory system and we smell through our respiratory system. The digestive tract includes the teeth, tongue, pharynx, esophagus, stomach, gallbladder, liver, small intestine, large intestine, and pancreas. We're going to take food in through our digestive tract and we'll be able to absorb as much nutrients and water that we possibly can through that food and then we will get rid of any waste. Urinary system is going to include the kidneys, ureters, bladder, and urethra. And the main job of the kidneys is to filter the blood. The kidneys are one of our greatest filters. filters. And by filtering the blood, we're going to take toxins and other ions and things that could build up or could be considered waste and we're going to be able to eliminate those or urinate those out, which is going to help keep the blood volume, pH, and nutrient balance correct. So this is part of our homeostasis. Next we have the male reproductive system, which will include the testes, epididymis, ductus deferens, seminal vesicles, prostate, penis, and scrotum. The main function of the male reproductive system is to produce sperm, seminal fluid, and also male hormones like testosterone. The female reproductive system includes ovaries, uterine tubes, uterus, vagina, labia, clitoris, and mammary glands. They function to produce female sex cells or oocytes, those are the ovaries, and also hormones like estrogen. The uterus will be responsible for developing the embryo from conception to delivery. And the mammary glands will produce milk under the aid of reproductive hormones to nourish the newborn. So those are the main high points of the organ systems. And again, we'll go through great detail. in each one as we move through. through the course. We should also be familiar with some anatomical terminology that we'll be able to use throughout the rest of the course as well. Surface anatomy is locating structures on or near the body surface. So again, on top. And the anatomical position is an important position to picture whenever we are using this anatomical terminology. We should all be picturing the body in the same position. That way the terms are meaningful, mean the same thing to me as they would to you. Anatomical position is hands at sides with palms forward, standing straight up. I believe I have a picture here. So this lady here is in the anatomical position. Hands at her sides, palms forward. Okay, so supine is lying down on your back, face up, palms up. Prone, lying down, face down, palms down. So he is also in the anatomical position, we just can't see all of his hand there. But this is also a good picture of surface anatomy. We're looking at landmarks on the surface of the body. We can also divide the abdomen into quadrants. And we'll in addition look at some anatomical direction terms. But let's start with the quadrants. So in this picture, you can see... the abdominal pelvic area, which is this area here, has been divided up by a line going straight through the belly button, up and down, and one going horizontally or side to side right through the belly button as well. And this creates the left upper quadrant, the right upper quadrant, the right lower quadrant, and the left lower quadrant. This is helpful because there is a lot of equipment in the abdominal pelvic cavity, a lot of organs, and so if a person has abdominal pain, it can be difficult to know exactly where it might be coming from. So if we're able to narrow down what quadrant the pain is in, and we know what organs are in that quadrant, it can speed up the search for the problem. So in the next image, you can see the same blue lines up and down through the belly. button, side to side, horizontally through the belly button, and we can see our quadrants and see what organs are in each quadrant. For now, ignore the red lines. So in the left upper quadrant, some of the key players would be the spleen and the stomach. In the right upper quadrant, we have most of the liver and the gallbladder. A lot of people have issues with their gallbladder and that will present with abdominal pain. Then down in the right lower quadrant we have the appendix, another area that can cause abdominal pain, and in females we would have the right ovary here. The left lower quadrant we would have the left ovary in females, and you can see the small and large intestines are here as well as the other quadrants. So in this image we're going to be able to look at directional terms or directional references. So some of the important ones we're going to see over and over again. Superior means above, toward the head. The opposite of that would be inferior below toward the feet. Medial is toward the midline. So if you imagine an imaginary line going straight through the middle. of the body that would be the midline so medial would be toward the midline lateral means away from the midline so out to the side away from the midline proximal means toward the point of attachment of a limb so this limb is the arm proximal means close to the point of attachment. So the point of attachment of the arm would be the shoulder. And then distal is away from the point of attachment of a limb. The hand would be distal from the point of attachment. Distal makes me think of distant from, and proximal makes me think of close to, as in in the proximity of. So proximal toward the point of attachment. away from the point of attachment. Superficial means on the body's surface or very close to the body surface. Deep is toward the interior of the body, far from the body. the surface. Cranial means toward the head or of the head. Caudal toward the tail. Now we don't have a tail but we do have a tail bone so caudal toward the tail. Anterior or ventral either one of those means the front surface the front surface anterior or ventral opposite of that that would be posterior or dorsal, the back surface. I always remember this by dorsal and dorsal fin. So the dorsal fin of a shark would be on its back. More than just a shark, but the shark is the one we all commonly do not want to see when we're at the beach, the one that cuts through the water. So dorsal back or posterior. Sectional anatomy is when we take a slice through a three-dimensional object. This helps us to be able to see internal organization. For example, we can divide the body. by using sectional planes. So a frontal or coronal plane is a vertical plane that will divide the body into a front and back, or anterior and posterior. So let's take a look at that. So in this image, this purple rectangle here represents a frontal plane. So a frontal plane divides the body vertically into a front and back or anterior and posterior. So again, this purple rectangle represents our frontal plane. And you can see when there is a frontal plane, this would allow us to see the internal organs very nicely like this. So next we have a sagittal plane, which is a vertical plane dividing the body into a left and right side. Now, a cut in this plane is called a sagittal section, but there are really two cuts. kinds of sagittal planes for us to talk about. Mid-sagittal plane lies perfectly in the middle, so this is going to divide you into an equal left and right half. Parasagittal plane is offset from the middle, so this is still a section or a plane that would divide you into left and right, but they are not necessarily equal halves. Okay, so this image will show us a mid-sagittal plane. So this blue rectangle shows a mid-sagittal plane cutting right through the body, dividing us into an equal. left and right side. Again, mid-sagittal equal left and right side. And we would end up with a nice image like this that allows us to see inside at the halfway. waypoint. Again, parasagittal is when we are not intersecting at the midline, so we're going to be offset from the midline. A transverse plane is a horizontal plane that divides the body into an upper and lower portion, or superior and inferior. A cut in this plane is called a transverse section, or cross section. So the green square here represents transverse. Horizontal plane dividing you into an upper and lower portion or superior and inferior. A transverse plane would give us a view like this one. Body cavities. Body cavities are going to protect organs from shock and impact and will allow the organs to change in size. size and shape as they move and work. The ventral body cavity is divided by the diaphragm and it's going to include the thoracic cavity and the abdominal pelvic cavity. So I'm going to show you these in a picture to help them seem a little bit more, a little easier to remember if we get a visual. Body cavities are also going to contain viscera. Viscera, again, fancy for internal organs. So let's go ahead to this picture and take a look at the thoracic cavity. So the thoracic cavity, chest cavity, is going to include the pleural cavity and the paracavity. pericardial cavity. So the pleural cavity is this one. This is the cavity that's going to contain the lungs and the pericardial cavity here is going to contain the heart. So pleural cavity, pericardial cavity together make up thoracic cavity. Okay. So we're going to go back and look at abdominal pelvic cavity as well in just a minute. Inside of the body cavities, we're going to have serous membranes. And serous membranes are membranes that are going to produce a... watery lubricant. These membranes again will line the body cavities and they're also going to cover the organs. We call the serosa or serous membrane that lines the body. cavity. Those are called parietal serosa, the ones that line the cavity. Visceral serosa will cover the organ itself, cover the organ itself. So again we've already looked at the picture of this, the thoracic cavity has a right and left pleural or lung cavity. Those will contain the right and left lungs. The mediastinum is a central tissue mass that divides the thoracic cavity into a right and left lung cavity or pleural cavity. So it's going to split that chest cavity right up into a right and left pleural cavity. It's also going to house blood vessels. The trachea and esophagus is all going to be right there. And again in the under or within the thoracic cavity. we've also got the pericardial cavity, which is where the heart is located. Okay, so once again here's our thoracic cavity with our pleural and pericardial cavity inside. Then we've got a division with the diaphragm here. Below the diaphragm is the abdominopelvic cavity. In the abdominopelvic cavity, within it is the peritoneal cavity. And the peritoneal cavity will have serosa like we talked about those membranes that produce a watery lubricant and this is going to help the organs to stay nice and slippery so that there's not much friction between them within the peritoneal cavity we have the abdominal cavity and at the bottom the pelvic cavity so reiterating peritoneal cavity is within the abdomen pelvic cavity and it has serosa that I previously mentioned. The specific names of the serosa are the parietal peritoneum. Parietal, remember that means lines the cavity. Visceral peritoneum covers the organs. Both of these are going to secrete that watery lubricant we talked about. Abdominal cavity is the peritoneum. top part of the abdominal pelvic cavity from the diaphragm right down to the top of your pelvic bones and this area is going to contain digestive organs things like intestines the small intestine large intestine and then we have the pelvic cavity which is the inferior portion of the abdominal pelvic cavity so down at the bottom medial to the pelvic bones remember medial means towards the midline, so in between the pelvic bones, we're going to find reproductive organs, rectum, and also the bladder. homeostasis all body systems work together to keep a stable internal environment your systems will respond to any external and internal changes to help keep any variation within normal range. This would include things like your body temperature or your fluid balance. I like to remember homeostasis as equilibrium or just simply balance. Your body has a change in temperature. checkpoint for a lot of these important things. For example, body temperature 98.6 and the body wants to remain within that normal range as much as possible. That's a huge goal. Now there are some times where we get out of that normal range temporarily, but the body's going to typically work very hard to try to keep us at homeostasis for a lot of things. Blood pH, body temperature, blood sugar, etc. Homeostasis is regulated in your body in two main ways. Auto-regulation, which is an automatic response in your cells, tissues, or organs to an environmental change. So in other words, it happens automatically. For example, we can all relate to those times when you wake up in the middle of the night and you've been laying on your arm, weirdly, and suddenly your arm, it almost feels like it isn't attached to you. It almost feels dead. You can tell that there's not much blood flow in it and sometimes it's even so out of whack that you have to pick up your arm and move it with the other arm. And often we start moving our hand and moving our fingers up and down to try to get the feeling back in the arm. And what typically happens is we get this pins and needles feeling that comes into the arm as we try to wake it up. That's an example of auto regulation. When blood flow was not what it should be, should be, to the arm, cells in your arm begin to release chemicals to cause your blood vessels to dilate, allowing more blood to rush into the area to get your oxygen levels back up again. We didn't have to use the nervous or endocrine system to help us fix this problem. It was an automatic or auto-regulation response. Automatic regulation is when we have to fix a homeostasis. problem using the nervous or endocrine systems. An example of this would be if you suddenly jump onto a treadmill and begin running full speed, the body needs more oxygen, blood to pump quicker to keep up with your energy or keep up with your activity. So the nervous system will cause the heart to beat faster to keep up with the activity level. level. So extrinsic regulation when we use the nervous system to get involved to keep our homeostasis in check. For example in keeping your oxygen levels up when you start running on a treadmill the nervous system causes the heart to beat faster. Homeostatic regulatory mechanism is going to consist of three main things. A receptor that receives the stimulus or as I like to simplify it, picks up on the problem. The control center will process what's going on with the problem and then send out instructions for how to fix the problem. The effector will carry out the instructions. This will limit the homeostatic fluctuation to keep them close to normal or the checkpoint that we really want. This is going to help keep us in that happy range. So whenever we fight change in homeostasis, we call this negative feedback. I like to remember this by thinking about negative feedback, the word negative, that negative feedback feels negatively about change. We are not going to embrace change. We're going to try to keep ourselves as close to set point or checkpoint as possible. So the response of the effector in a negative feedback loop will negate the stimulus so that the body is brought back to homeostasis and we stay normal and happy. So an example of this, I have a little crude drawing from my study guide that I've included in my study guide. included here, but this is kind of an everyday example to help it be a little bit more relatable. So just like inside of our body where our little thermostat is set at 98.6, we do this as well in our homes. We set our thermostat for a checkpoint that we want our home to be. So in this case, let's say our checkpoint is 70. We'd like our home temperature to be 70. If it's a very cold winter day, lots of cold air outside, the room may become too cold inside the house. We've all experienced this. Temperature sensitive switch will activate the heater to turn on. The heater turns on and the room begins to heat up. It may heat up a little past checkpoint, maybe to 72 degrees. The thermostat will then shut off the heat. and the room will begin to cool down a little. And guess where we are? Back at 70, which is where we want to be in the first place. And this is going to continue and fluctuate off and on all day long. as the temperature fluctuates. But we're going to stay within a range that's not dangerous as far as our body temperature is concerned. It's going to fluctuate a little, but we're going to stay within a healthy range. So here's the human body example that kind of goes with my everyday example. So 98.6 degrees Fahrenheit or 37-ish for Celsius. If we're outside, we're going to have a lot of heat. and we're being active and our body temperature starts to go up a little bit, receptors, body temperature receptors, pick up that we're getting a little hot. A message is sent to the control center, which is your brain, the thermoregulatory center in the brain which is your hypothalamus will send a command to the effectors remember the effectors fix the problem so in this case the effectors are blood vessels and sweat glands in your skin blood vessels will dilate increased blood flow close to the surface of the skin will allow heat to leave through the skin we will begin to sweat more and this will help to bring our body temperature back down to normal. So this is an example of a negative feedback loop. The same is true if we get a little cold. So if our body temperature starts to go down a little because we're really cold, temperature receptors in our body send a message to the control center, which is our brain, hypothalamus, The brain sends a command to the effectors who fix the problem. And in this instance, blood vessels will decrease blood flow to the skin so that we don't lose body heat. We'll decrease our sweating and our muscles will begin to shiver, which helps us to burn energy and make extra heat. So that'll help to warm us up. and our temperature will be restored. So again, a negative feedback loop to keep us as close to that 98.6 as possible. We resisted change. Now, on the opposite end of the spectrum, we have what's called positive feedback. And I like to remember that positive feedback feels positively about change. In positive feedback, an initial stimulus will produce a response that amplifies simplifies the original change. The body is moved away from homeostasis. We do not stay in normal range. Positive feedback loops are often dangerous, but it's going to be quick and then we will reestablish our homeostasis afterwards. So again, boiling that down, positive feedback feels positively about change and what's going to happen in positive feedback. is we're gonna temporarily make the change worse so that a big event can occur or an event can occur and then when that event is finished we are then going to return to our initial homeostasis so again positive feedback exaggerates change makes it worse so here's an example again taken from my study guide during childbirth so this is a uterus and here's the cervix which is what dilates during childbirth. The fetal head will put pressure on the cervix, which will stimulate the release of oxytocin. And oxytocin is a hormone that causes the uterus to contract. Contractions equal baby coming out, so we want that. So as it says, oxytocin will stimulate uterine contractions, which will help to push the baby downward, further stimulating the cervix, So more oxytocin is released, labor contractions become more intense. This is the amplification of the change. We're getting more and more and more intense, worse and worse and worse, further and further and further from homeostasis until we have full dilation and expulsion of the fetus. Okay, so this is certainly not an everyday normal range situation. childbirth is pretty extreme. So in this case, oxytocin, which is not normally present in high levels in the blood, is going to amplify and go up, which takes us away from homeostasis. But we need to be away from homeostasis in order for this baby to be born. So positive feedback will allow that oxytocin to increase and the contractions to increase incrementally until baby... is born, once baby is born we can start moving back towards homeostasis. So this is a good thing, a good example of getting away from normal for a big event like childbirth to take place. And this is the end of chapter 1, Anatomy 1, and we'll get started soon on chapter 2, Anatomy 1, which will go over basic chemistry and biochemistry.

The easiest way to boil this down is to just say that anatomy is what things look like. So if you're studying the structure of the heart and the blood vessels that meet with the heart, you would be looking at the anatomy. Physiology is the study of the functions of those anatomical structures, and the easiest way to describe physiology would just be how things work.

So in order to really understand the human body well, we need to put them together. You could be an anatomy expert and know nothing about how those organs work. So by knowing the physiology, we can tie all of that together and get a very deep understanding of that particular organ or system.

Anatomy can be divided up into subcategories. Gross anatomy also... known as macroscopic, macro meaning large, or visible without magnification, so we'd be able to easily see this without using a microscope or any other type of magnification. First, we have surface anatomy, and this is when we are literally studying the surface of something, looking at just the exterior or outside parts of the body without any dissection.

Occasional anatomy is is looking at a specific body area. For example, if you wanted to study the musculature of the head and neck specifically, that would be a region. Sectional anatomy is when we take cross sections through the body and study those cross sections like is often done in a CT scan or MRI. Systemic anatomy is the study of the individual organ systems. So So looking at the cardiovascular system specifically, for example.

Clinical anatomy is the medical specialty subcategory, like when we look at tissues in pathology, for example. Developmental anatomy is the study from conception to adulthood. So this would be including embryology. So studying embryology and then fetal development.

and so on. Microscopic anatomy is when we do have to use magnification to study the anatomy. So this would be things like cells and molecules. Cytology is the study of cells and histology is the study of tissues. We will review this a little more later but tissues are collections of cells that are working together to perform very specific functions.

So histology would be the study of those tissues. Physiology, or how things work, can also be divided up. Cell physiology is the study of the function of the individual cells. We're going to look a little more into that in chapter three. Organ physiology is looking at the function of the whole organ.

Systemic physiology is looking at the function of the whole organ system. We're going to be doing some of both of those in addition to cell physiology. Pathological physiology is the effects of disease on the specific organs we're talking about.

So to start at the beginning and really get a good understanding of the cell and then the tissue and then the organ and organ system, we need to remember what the hierarchy of life is or the levels of organization. And this is something that is often talked about in general biology. So we start at the bottom where we find the atoms.

And atoms are the smallest, most stable units of matter. And when we combine atoms with... specific types of bonds, we get molecules. These are groups of atoms.

Examples would be things like proteins. Complex molecules can form larger structures called organelles and these are the tiny parts that are inside of the cell that have very specific functions. You might remember from biology the mitochondria, the nucleus, the rough and smooth endoplasmic reticulum, for example.

If we group up the organelles, including the cell membrane, we get the cell, which is the smallest living unit in the human body. If we group similar cells together that work as a team, we get the tissue level. If we group tissues together and these tissues are similar, then we get the tissue level.

organs. If we put the organs accessories or organs that work with it together we get the organ system. Humans have 11 organ systems which we will eventually cover all of and if we combine all 11 organ systems together we get the whole organism. So to review that through picture we have atoms atoms combine to form molecules like this complex protein.

Molecules can combine to form organelles. We talked about things again like the mitochondria, the rough and smooth endoplasmic reticulum, and then we can group the organelles together with the membrane to get the whole cell like this heart muscle cell for example. If we group other heart muscle cells with this one, we get cardiac or heart muscle tissue. And all the tissues that are similar, that work together combined, will make the heart. And if we put in the blood vessels, like the arteries, veins, and capillaries, we get the entire cardiovascular system.

And if we put all the other systems in, then we get the entire cardiovascular system. then we get to the organism level or the top. So here are part of the organ systems and in chapter one all we really do is just go over a very light overview of the main organs and the main functions.

Nothing too deep yet. We'll individually take those systems later and go over them in great detail. So starting at first with the integumentary system. fancy for skin and this is going to include the skin and anything that grows out of the skin so the hair sweat glands nails all grow out of the skin the function of your skin is to protect you number one against anything outside environmental hazards bacteria it's also going to help regulate your body temperature you've got fat in your skin that helps to keep you warm and you And you also sweat when you get hot and this is going to help you to cool down. Your skin also contains lots of sensory nerves so we can feel through our skin.

Next we have the skeletal system and the skeletal system is going to include bones, cartilage, ligaments and also bone marrow. The bones are going to support and protect your body, give you structure and also when we talk about protection. specifically mean protecting vital organs like the skull protects the brain and the ribcage and sternum are going to protect the heart and lungs. We also store calcium and other minerals in our skeleton and our bone marrow is responsible for forming blood cells. Next we have the muscular system which is made up of skeletal muscles and tendons.

Muscle Muscles are going to provide movement and they also will support soft areas as well. By moving our muscles we generate body heat and that helps to keep us warm. The nervous system includes brain, spinal cord, nerves, and sense organs like the eyes.

The nervous system is important because its job is going to be to direct responses to stimuli that your brain is going to be able to control. nervous system perceives. So if a bright light shines in your eye or you hear a noise behind you, your nervous system will be able to interpret what you're seeing or hearing or feeling. It also gives you conscious awareness and allows you to understand your surroundings, what's going on around you, and coordinate activities of other organ systems. The endocrine system is going to include some major glands like the pituitary and thyroid gland, pancreas, adrenal, gonads, and any other tissue that makes hormones, which is primarily what the endocrine system is responsible for.

These hormones are chemical messengers that are going to direct long-term changes in your body. These hormones can adjust your metabolism and also help with structural and functional development. Cardiovascular system includes the heart, blood, and blood vessels.

It's responsible for distributing blood around the body and this is important because the blood is going to contain dissolved gases like oxygen and carbon dioxide and in addition to that we're going to use the blood to distribute nutrients throughout the body to the cells. Your blood flowing also helps to distribute your body heat to help maintain your core body temperature. Next we have the lymphatic system and the lymphatic system is responsible for immunity. So this is going to include the spleen, thymus, lymphatic vessels, which remind me a bit of blood vessels.

run all along the body and also your lymph nodes and tonsils. Since this is considered your immune system it's going to defend against infection and disease and also help to return tissue fluid to the bloodstream. The respiratory system is going to include your nasal cavities, sinuses, larynx, trachea, bronchi, lungs, and alveoli.

Primarily the respiratory system is responsible for your breathing. So we're going to bring air into the lungs where we can get oxygen from that air and we're going to deliver CO2. from the body to the lungs so that we're able to exhale it. We can also talk through our respiratory system and we smell through our respiratory system. The digestive tract includes the teeth, tongue, pharynx, esophagus, stomach, gallbladder, liver, small intestine, large intestine, and pancreas.

We're going to take food in through our digestive tract and we'll be able to absorb as much nutrients and water that we possibly can through that food and then we will get rid of any waste. Urinary system is going to include the kidneys, ureters, bladder, and urethra. And the main job of the kidneys is to filter the blood.

The kidneys are one of our greatest filters. filters. And by filtering the blood, we're going to take toxins and other ions and things that could build up or could be considered waste and we're going to be able to eliminate those or urinate those out, which is going to help keep the blood volume, pH, and nutrient balance correct.

So this is part of our homeostasis. Next we have the male reproductive system, which will include the testes, epididymis, ductus deferens, seminal vesicles, prostate, penis, and scrotum. The main function of the male reproductive system is to produce sperm, seminal fluid, and also male hormones like testosterone.

The female reproductive system includes ovaries, uterine tubes, uterus, vagina, labia, clitoris, and mammary glands. They function to produce female sex cells or oocytes, those are the ovaries, and also hormones like estrogen. The uterus will be responsible for developing the embryo from conception to delivery.

And the mammary glands will produce milk under the aid of reproductive hormones to nourish the newborn. So those are the main high points of the organ systems. And again, we'll go through great detail.

in each one as we move through. through the course. We should also be familiar with some anatomical terminology that we'll be able to use throughout the rest of the course as well. Surface anatomy is locating structures on or near the body surface.

So again, on top. And the anatomical position is an important position to picture whenever we are using this anatomical terminology. We should all be picturing the body in the same position.

That way the terms are meaningful, mean the same thing to me as they would to you. Anatomical position is hands at sides with palms forward, standing straight up. I believe I have a picture here.

So this lady here is in the anatomical position. Hands at her sides, palms forward. Okay, so supine is lying down on your back, face up, palms up.

Prone, lying down, face down, palms down. So he is also in the anatomical position, we just can't see all of his hand there. But this is also a good picture of surface anatomy.

We're looking at landmarks on the surface of the body. We can also divide the abdomen into quadrants. And we'll in addition look at some anatomical direction terms. But let's start with the quadrants. So in this picture, you can see...

the abdominal pelvic area, which is this area here, has been divided up by a line going straight through the belly button, up and down, and one going horizontally or side to side right through the belly button as well. And this creates the left upper quadrant, the right upper quadrant, the right lower quadrant, and the left lower quadrant. This is helpful because there is a lot of equipment in the abdominal pelvic cavity, a lot of organs, and so if a person has abdominal pain, it can be difficult to know exactly where it might be coming from.

So if we're able to narrow down what quadrant the pain is in, and we know what organs are in that quadrant, it can speed up the search for the problem. So in the next image, you can see the same blue lines up and down through the belly. button, side to side, horizontally through the belly button, and we can see our quadrants and see what organs are in each quadrant.

For now, ignore the red lines. So in the left upper quadrant, some of the key players would be the spleen and the stomach. In the right upper quadrant, we have most of the liver and the gallbladder.

A lot of people have issues with their gallbladder and that will present with abdominal pain. Then down in the right lower quadrant we have the appendix, another area that can cause abdominal pain, and in females we would have the right ovary here. The left lower quadrant we would have the left ovary in females, and you can see the small and large intestines are here as well as the other quadrants. So in this image we're going to be able to look at directional terms or directional references. So some of the important ones we're going to see over and over again.

Superior means above, toward the head. The opposite of that would be inferior below toward the feet. Medial is toward the midline.

So if you imagine an imaginary line going straight through the middle. of the body that would be the midline so medial would be toward the midline lateral means away from the midline so out to the side away from the midline proximal means toward the point of attachment of a limb so this limb is the arm proximal means close to the point of attachment. So the point of attachment of the arm would be the shoulder. And then distal is away from the point of attachment of a limb.

The hand would be distal from the point of attachment. Distal makes me think of distant from, and proximal makes me think of close to, as in in the proximity of. So proximal toward the point of attachment.

away from the point of attachment. Superficial means on the body's surface or very close to the body surface. Deep is toward the interior of the body, far from the body. the surface.

Cranial means toward the head or of the head. Caudal toward the tail. Now we don't have a tail but we do have a tail bone so caudal toward the tail. Anterior or ventral either one of those means the front surface the front surface anterior or ventral opposite of that that would be posterior or dorsal, the back surface. I always remember this by dorsal and dorsal fin.

So the dorsal fin of a shark would be on its back. More than just a shark, but the shark is the one we all commonly do not want to see when we're at the beach, the one that cuts through the water. So dorsal back or posterior. Sectional anatomy is when we take a slice through a three-dimensional object.

This helps us to be able to see internal organization. For example, we can divide the body. by using sectional planes.

So a frontal or coronal plane is a vertical plane that will divide the body into a front and back, or anterior and posterior. So let's take a look at that. So in this image, this purple rectangle here represents a frontal plane. So a frontal plane divides the body vertically into a front and back or anterior and posterior.

So again, this purple rectangle represents our frontal plane. And you can see when there is a frontal plane, this would allow us to see the internal organs very nicely like this. So next we have a sagittal plane, which is a vertical plane dividing the body into a left and right side. Now, a cut in this plane is called a sagittal section, but there are really two cuts. kinds of sagittal planes for us to talk about.

Mid-sagittal plane lies perfectly in the middle, so this is going to divide you into an equal left and right half. Parasagittal plane is offset from the middle, so this is still a section or a plane that would divide you into left and right, but they are not necessarily equal halves. Okay, so this image will show us a mid-sagittal plane. So this blue rectangle shows a mid-sagittal plane cutting right through the body, dividing us into an equal. left and right side.

Again, mid-sagittal equal left and right side. And we would end up with a nice image like this that allows us to see inside at the halfway. waypoint. Again, parasagittal is when we are not intersecting at the midline, so we're going to be offset from the midline. A transverse plane is a horizontal plane that divides the body into an upper and lower portion, or superior and inferior.

A cut in this plane is called a transverse section, or cross section. So the green square here represents transverse. Horizontal plane dividing you into an upper and lower portion or superior and inferior.

A transverse plane would give us a view like this one. Body cavities. Body cavities are going to protect organs from shock and impact and will allow the organs to change in size.

size and shape as they move and work. The ventral body cavity is divided by the diaphragm and it's going to include the thoracic cavity and the abdominal pelvic cavity. So I'm going to show you these in a picture to help them seem a little bit more, a little easier to remember if we get a visual. Body cavities are also going to contain viscera. Viscera, again, fancy for internal organs.

So let's go ahead to this picture and take a look at the thoracic cavity. So the thoracic cavity, chest cavity, is going to include the pleural cavity and the paracavity. pericardial cavity. So the pleural cavity is this one. This is the cavity that's going to contain the lungs and the pericardial cavity here is going to contain the heart.

So pleural cavity, pericardial cavity together make up thoracic cavity. Okay. So we're going to go back and look at abdominal pelvic cavity as well in just a minute. Inside of the body cavities, we're going to have serous membranes. And serous membranes are membranes that are going to produce a...

watery lubricant. These membranes again will line the body cavities and they're also going to cover the organs. We call the serosa or serous membrane that lines the body. cavity.

Those are called parietal serosa, the ones that line the cavity. Visceral serosa will cover the organ itself, cover the organ itself. So again we've already looked at the picture of this, the thoracic cavity has a right and left pleural or lung cavity. Those will contain the right and left lungs.

The mediastinum is a central tissue mass that divides the thoracic cavity into a right and left lung cavity or pleural cavity. So it's going to split that chest cavity right up into a right and left pleural cavity. It's also going to house blood vessels.

The trachea and esophagus is all going to be right there. And again in the under or within the thoracic cavity. we've also got the pericardial cavity, which is where the heart is located.

Okay, so once again here's our thoracic cavity with our pleural and pericardial cavity inside. Then we've got a division with the diaphragm here. Below the diaphragm is the abdominopelvic cavity.

In the abdominopelvic cavity, within it is the peritoneal cavity. And the peritoneal cavity will have serosa like we talked about those membranes that produce a watery lubricant and this is going to help the organs to stay nice and slippery so that there's not much friction between them within the peritoneal cavity we have the abdominal cavity and at the bottom the pelvic cavity so reiterating peritoneal cavity is within the abdomen pelvic cavity and it has serosa that I previously mentioned. The specific names of the serosa are the parietal peritoneum. Parietal, remember that means lines the cavity.

Visceral peritoneum covers the organs. Both of these are going to secrete that watery lubricant we talked about. Abdominal cavity is the peritoneum. top part of the abdominal pelvic cavity from the diaphragm right down to the top of your pelvic bones and this area is going to contain digestive organs things like intestines the small intestine large intestine and then we have the pelvic cavity which is the inferior portion of the abdominal pelvic cavity so down at the bottom medial to the pelvic bones remember medial means towards the midline, so in between the pelvic bones, we're going to find reproductive organs, rectum, and also the bladder. homeostasis all body systems work together to keep a stable internal environment your systems will respond to any external and internal changes to help keep any variation within normal range.

This would include things like your body temperature or your fluid balance. I like to remember homeostasis as equilibrium or just simply balance. Your body has a change in temperature. checkpoint for a lot of these important things.

For example, body temperature 98.6 and the body wants to remain within that normal range as much as possible. That's a huge goal. Now there are some times where we get out of that normal range temporarily, but the body's going to typically work very hard to try to keep us at homeostasis for a lot of things. Blood pH, body temperature, blood sugar, etc.

Homeostasis is regulated in your body in two main ways. Auto-regulation, which is an automatic response in your cells, tissues, or organs to an environmental change. So in other words, it happens automatically. For example, we can all relate to those times when you wake up in the middle of the night and you've been laying on your arm, weirdly, and suddenly your arm, it almost feels like it isn't attached to you. It almost feels dead.

You can tell that there's not much blood flow in it and sometimes it's even so out of whack that you have to pick up your arm and move it with the other arm. And often we start moving our hand and moving our fingers up and down to try to get the feeling back in the arm. And what typically happens is we get this pins and needles feeling that comes into the arm as we try to wake it up. That's an example of auto regulation. When blood flow was not what it should be, should be, to the arm, cells in your arm begin to release chemicals to cause your blood vessels to dilate, allowing more blood to rush into the area to get your oxygen levels back up again.

We didn't have to use the nervous or endocrine system to help us fix this problem. It was an automatic or auto-regulation response. Automatic regulation is when we have to fix a homeostasis.

problem using the nervous or endocrine systems. An example of this would be if you suddenly jump onto a treadmill and begin running full speed, the body needs more oxygen, blood to pump quicker to keep up with your energy or keep up with your activity. So the nervous system will cause the heart to beat faster to keep up with the activity level.

level. So extrinsic regulation when we use the nervous system to get involved to keep our homeostasis in check. For example in keeping your oxygen levels up when you start running on a treadmill the nervous system causes the heart to beat faster.

Homeostatic regulatory mechanism is going to consist of three main things. A receptor that receives the stimulus or as I like to simplify it, picks up on the problem. The control center will process what's going on with the problem and then send out instructions for how to fix the problem.

The effector will carry out the instructions. This will limit the homeostatic fluctuation to keep them close to normal or the checkpoint that we really want. This is going to help keep us in that happy range.

So whenever we fight change in homeostasis, we call this negative feedback. I like to remember this by thinking about negative feedback, the word negative, that negative feedback feels negatively about change. We are not going to embrace change.

We're going to try to keep ourselves as close to set point or checkpoint as possible. So the response of the effector in a negative feedback loop will negate the stimulus so that the body is brought back to homeostasis and we stay normal and happy. So an example of this, I have a little crude drawing from my study guide that I've included in my study guide.

included here, but this is kind of an everyday example to help it be a little bit more relatable. So just like inside of our body where our little thermostat is set at 98.6, we do this as well in our homes. We set our thermostat for a checkpoint that we want our home to be.

So in this case, let's say our checkpoint is 70. We'd like our home temperature to be 70. If it's a very cold winter day, lots of cold air outside, the room may become too cold inside the house. We've all experienced this. Temperature sensitive switch will activate the heater to turn on.

The heater turns on and the room begins to heat up. It may heat up a little past checkpoint, maybe to 72 degrees. The thermostat will then shut off the heat. and the room will begin to cool down a little. And guess where we are?

Back at 70, which is where we want to be in the first place. And this is going to continue and fluctuate off and on all day long. as the temperature fluctuates. But we're going to stay within a range that's not dangerous as far as our body temperature is concerned. It's going to fluctuate a little, but we're going to stay within a healthy range.

So here's the human body example that kind of goes with my everyday example. So 98.6 degrees Fahrenheit or 37-ish for Celsius. If we're outside, we're going to have a lot of heat.

and we're being active and our body temperature starts to go up a little bit, receptors, body temperature receptors, pick up that we're getting a little hot. A message is sent to the control center, which is your brain, the thermoregulatory center in the brain which is your hypothalamus will send a command to the effectors remember the effectors fix the problem so in this case the effectors are blood vessels and sweat glands in your skin blood vessels will dilate increased blood flow close to the surface of the skin will allow heat to leave through the skin we will begin to sweat more and this will help to bring our body temperature back down to normal. So this is an example of a negative feedback loop. The same is true if we get a little cold. So if our body temperature starts to go down a little because we're really cold, temperature receptors in our body send a message to the control center, which is our brain, hypothalamus, The brain sends a command to the effectors who fix the problem.

And in this instance, blood vessels will decrease blood flow to the skin so that we don't lose body heat. We'll decrease our sweating and our muscles will begin to shiver, which helps us to burn energy and make extra heat. So that'll help to warm us up.

and our temperature will be restored. So again, a negative feedback loop to keep us as close to that 98.6 as possible. We resisted change. Now, on the opposite end of the spectrum, we have what's called positive feedback. And I like to remember that positive feedback feels positively about change.

In positive feedback, an initial stimulus will produce a response that amplifies simplifies the original change. The body is moved away from homeostasis. We do not stay in normal range. Positive feedback loops are often dangerous, but it's going to be quick and then we will reestablish our homeostasis afterwards. So again, boiling that down, positive feedback feels positively about change and what's going to happen in positive feedback.

is we're gonna temporarily make the change worse so that a big event can occur or an event can occur and then when that event is finished we are then going to return to our initial homeostasis so again positive feedback exaggerates change makes it worse so here's an example again taken from my study guide during childbirth so this is a uterus and here's the cervix which is what dilates during childbirth. The fetal head will put pressure on the cervix, which will stimulate the release of oxytocin. And oxytocin is a hormone that causes the uterus to contract. Contractions equal baby coming out, so we want that. So as it says, oxytocin will stimulate uterine contractions, which will help to push the baby downward, further stimulating the cervix, So more oxytocin is released, labor contractions become more intense.

This is the amplification of the change. We're getting more and more and more intense, worse and worse and worse, further and further and further from homeostasis until we have full dilation and expulsion of the fetus. Okay, so this is certainly not an everyday normal range situation.

childbirth is pretty extreme. So in this case, oxytocin, which is not normally present in high levels in the blood, is going to amplify and go up, which takes us away from homeostasis. But we need to be away from homeostasis in order for this baby to be born.

So positive feedback will allow that oxytocin to increase and the contractions to increase incrementally until baby... is born, once baby is born we can start moving back towards homeostasis. So this is a good thing, a good example of getting away from normal for a big event like childbirth to take place.

And this is the end of chapter 1, Anatomy 1, and we'll get started soon on chapter 2, Anatomy 1, which will go over basic chemistry and biochemistry.

Transcript for:Introduction to Anatomy and Physiology

Transcript for:
Introduction to Anatomy and Physiology