Transcript for:
Introduction to the Human Body

in today's lecture we're going to begin our introduction to the human body there's two main things we're going to focus on today first an overview of anatomy and then second delve into something called gross anatomy as always before you proceed to the next lecture make sure you understand these learning objectives here and then these learning objectives here okay so let's go aad and get started talking about an overview of anatomy so the first question you want to ask yourself is why would we study human anatomy what's the point you know how is anatomy important in your life right well first of all how's it important in your job well if you're interested in becoming a physician or a nurse or an athletic trainer uh anything in the health profession you could a physical therapist for example you could really see how human anatomy very important obviously so human anatomy is very important in that regard let's look at other things as well even if you're not going to the Health Professions it's very important throughout your life in terms of leisure activities uh physical fitness is shown to help you physically mentally emotionally throughout your life and it's important that you understand the human body uh and how to maintain so you can enjoy these activities throughout your life and then finally all of us at some point will encounter a situation where we're sick we have to go to the doctor and we really want to be able to communicate to our doctor uh in an appropriate manner make sure we can describe what's going wrong with our body and make sure that the physician is able to uh explain to us what's going on and how we can fix a situation and if we both have an understanding of human anatomy that will really help facilitate that type of discussion okay so the next question we want to delve into is how are anatomy and physiology related so we're going to really focus on Anatomy but we cannot ignore something that's called physiology as well let's look at this so what is anatomy so Anatomy is the study or the Str of the structure or form of the human body in other words saying what is this what is that that's a hand this is a clavicle bone uh you know this is your skin that type of thing a very closely related field is something called physiology and this is the study of body function so another words not only is that a clavical bone but how is it formed what does it do you know not only is that your bicep muscle but how does the bicep muscle perform so you could see that although we're focusing on Anatomy it's not just enough to identify something you have to have some idea as well in terms of what it does in terms of its physiology in terms of its function so if we look at the two we say structure and function we would always say that you know function follows structure right the way something is formed the structure enables it to provide a certain function to the body and the two are very intricately related as you can see so that's what arrow is representing you can't look at one without looking at the other okay a quick example of that if we look at the human eye which we'll cover much later on in a different lecture you could see that we have something here called the cornea right and the cornea is this transparent tissue at the surface of the eye it's very important that it's transparent that's the anatomy that's the structure why is it important well if it's transparent then it can allow light to pass through it and that helps you see so you can see that's a classical case of uh function following structure and it shows the interplay between anatomy and physiology ology also when we talk about Anatomy we really want to make sure we understand the different functional levels uh that we can study anatomy at the organismal level and then uh below the organismal level as well so for example uh whenever we start talking about you know Anatomy or biology in general we start at the chemical level right the atoms the molecules that are used to form these structures we can up it to the cellular level the cell is the basic unit of life uh often has a membrane as you could see here this phospholipid membrane uh which forms the outer uh lining of a cell and that allows that barrier allows for different chemical reactions to proceed back and forth across the membrane you'll see that as a theme throughout uh this course throughout our lectures we also talk about the issue of the tissue level right then go to the organ level the organ system level and then finally the organismal level so um this is sort of an overview slide showing you the different levels and we'll encounter them throughout this uh throughout this course and throughout these lectures okay so in anatomy and in science in general we use something called the metric system it's a way of measuring things so we don't use inches or feet like we do in the United States uh rather in science and in most of the world we use something called the metric system so for example if we look at the bottom of the screen here and we have this little scale bar here this is about half the length of this individual uh if someone's 6 feet tall they're a little under 2 m so that bar would represent a meter if we go a little bit smaller here we put a new scale bar and this one I have to highlight because it's very tiny but right there that little red bar that would represent something called a centimeter right or 1/ 100th of a meter if we go even further down we can talk about something called a micrometer and I can't even draw the scale bar here because it's too small but if we focus on the micrometer and the nucleus of a given cell might be around 10 micrometers or so to give you an idea a micrometer is 1 1 millionth of a meter so 10 the -6 and this is something you'll encounter throughout the course so if we look at common measurements we might say a liter as a unit of volume right a milliliter is 1 1,000th of that uh we're very familiar with these uh like a liter of Coke for example or maybe um if you're giving medicine to a small child you might measure that medicine in milliliters we could talk about a gram right we weighing food let's say or a kilogram which is a th000 grams these are units that we use you know throughout anatomy and you'll see them many many times uh throughout our lectures okay so when the rubber hits the road what do you have to know here what's going to be on the test uh number one we want to focus on learning but I think it's quite naive to not consider what's on the test right that's very important as well it's a practical consideration we have to consider so certainly let's not obsess with what's on the test but it would be very wise to know you know what we will be tested on and so if we look at this chart really the thing I'm focusing on here is this highlighted portion where I have the red box around it if you know those values those abbreviations and then the multiplier all right in terms of you know how high or how low those prefixes uh enable the number to go uh that would be sufficient for an anatomy course I think it's a solid uh Foundation okay so let's talk about how anatomical terms are named well a lot of these names come from the ancient Greek or from Latin right from the Roman Empire for example arm comes from the word brachium in Greek thigh comes from the word femur in Latin and it's really important that we use these terms because we need a standard nomenclature worldwide other words there's you know probably hundreds or maybe thousands of languages spoken throughout the world and if a physician or anyone from one country is talking to another physician or anyone else from another country you have to know what part of the body you're talking about and so by using this common language this common nomenclature is the word we use of ancient Greek and Latin we have a very standard way of naming things okay so that's a little overview of anatomy now I'd like to focus on something called gross anatomy so what is gross anatomy is it disgusting well sometimes right but really what gross means is large right so gross anatomy is something you could see with your eye and it's something uh that you don't need the aid of an instrument to see so we don't need a microscope right if we need a microscope that's microscopic Anatomy but if we can look at it with the eye that's gross anatomy so for example if we're naming the different muscles throughout the body that would be gross anatomy something we could see with our naked eye and we'll encounter both of these uh as we continue on in our anatomy course okay so what approaches are used to study gross anatomy well there's two main ones I want to focus on uh we'll use one of these two and then I will mention something as a side note as well a third approach that's often used so the first one is something called regional anatomy and regional anatomy is we're focusing on a given region right or area of the body so for example if we were focusing on the head region here uh if we were focusing on the muscles the nerves uh the bones all in the head region that would be regional anatomy uh really that's something that you would learn if you went to medical school or Graduate School uh for example a surgeon might really have to know regional anatomy very well because if they're operating on your draw your jaw let's say they're cracking your upper jaw to expand it or repairing a jaw that was broken you know I hope they would know what muscles are there or what nerves are there otherwise they might be cutting through muscles and damaging nerves that are very important uh for for movement of your face so Regional anatom is very important but it's something that we maybe study more at an upper level what we're going to use in this course is something called systemic Anatomy so by systemic Anatomy what we mean is we're covering one system at a time so for example we might start by focusing on the cardiovascular system right looking at uh the system that has all these common uh attributes so in other words we have the heart we have the blood vessels pumping blood through the body that's a really great approach uh to use because it's very good in relating structure to function so it's a great way to introduce uh someone to Anatomy so it's something that we really use at the undergraduate level something else I want to mention and it's covered by my little icons in the bottom left here but I think you could probably uh see it okay is that there's another uh approach to Anatomy called surface anatomy and this is using uh surface structures or markings to reveal underlying organs uh it's something that a physician might use during an exam and so we'll talk about that a little bit later on in this lecture but in this course again just to emphasize we're really going to be focusing on the systemic Anatomy it's a good approach to use to relate structure to function okay so what are the body's organ systems and their major functions well here's six out of the 12 that we're going to be studying I'll let you read through these on your own and you might say okay this stage in the game what do I have to know well really what you have to know at this stage in the game is I'd like you to be able to identify each of these systems what are they what are the names and then just the one or two sentence uh description that's provided on this slide later on in this course we're going to be going much more in depth into each of these but for the first lecture here I want you to understand these Basics so you know in general what each system does and what it's called here are six more systems and the same thing applies to this slide so again just make sure you know the labels that are on this slide and the descriptions that go with each picture and we'll talk about these more throughout the course okay so when we talk about gross anatomy we really want to know where something is located and we have to use objective standards right we can't just say it's over there over here or it's up or it's down because when you think about it those terms might easily be confused so really what we're doing here is we need to First say okay what is the specimen or what is the subject going to look like you know uh in other words they always have to be in the same location or the same orientation we can't have someone l L down someone standing up uh someone curled up in the fetal position how are we going to describe where we're going with that you know in terms of for operating on someone we wouldn't know so really in anatomy we have something that's called the anatomical position and it looks something like this so you'll see an individual looking right back at you from the computer here that person is in the anatomical position you'll notice that that person's feet are flat on the ground the toys are pointed straight at you you'll also notice that the Palms here are facing towards you right and the Palms are open and the person's looking directly at you that's the anatomical position and when we're in that position we want to be able to know right from left this is right this is left you might say wait a second are those labels switched the answer is no they're not right in the at an atomical position when we say right we mean the person's right right the subject being studied their right so not your right but their right so that's why this is right over here and then this is left over here okay so how do we know what region of the body something's located in well there's a few different things we want to note here so the first is we could have something called the anterior side of the body or the posterior side of the body uh ventral and dorsal really apply more to animals right uh that are walking on four limbs so uh anterior and vental are basically synonyms posterior and dorsal are basically synonyms but in this course I'm going to talk about anterior for the human and then posterior for the human so the anterior position is is this it's the front of someone's body while the posterior position is the back of somebody's body also we can say what is the axial region of someone's body and the axial region is really saying their trunk right saying their trunk so that's really what you're talking about the trunk or the center portion of the body like it's an axis right so that's the axial region if we look at the axial region a bit further we could say it's divided into different categories so the thoracic region is sort of the chest region the abdomen is you know where your uh belly button is that region and your ab muscles right your abdominal muscles and um also we could say that there's the back region right and so if someone's looking you're looking at the posterior side you can see the back region again we use these so we can talk about which organs are lying in certain parts of the body okay if we get a little more technical if we're talking about the head we call it the calic region if we're talking about the neck we call it the cervical region thoracic is going to be the chest abdominal that's sort of a common word so we're sort of used to that right the abdominal region pelvic regions just below the abdominal region then finally the pubic region or the genital region you could see these on uh the posterior view as well so I'll just have those sort of pop up there okay the next region I want to talk about is something called the appendicular region and the appendicular region what we're saying by that is we're saying the limbs the individual's limbs their arms and legs so we could talk about the Upper Limb the Manis or the hand Manis in uh Latin means hand it's also my understanding that I think mono in Spanish means hand so you could see that languages that have derived from Latin or from ancient Greek If someone knows those languages they're really at an advantage when they talk about human anatomy because if you know mono means hand in Spanish then you know what hand is so it's really helpful if you have some basis in Latin or ancient Greek or any language that derived from those okay we can talk about the lower limb that's also part of the endic region and then the petal or the foot okay so how do we know what direction we're referring to how do we know what direction we're referring to if a surgeon's ready to operate we can't just say go that way or go this way it might get very confusing right you want to make sure that they're operating on the correct region of the body so we use some very precise terms when we're talking about human anatomy and they come in pairs so I encourage you to think of them in pairs the first pair is this if we say something is superficial we're saying it's toward the head if we say it's inferior I'm sorry I say I think I misspoke if we say it's Superior it's towards the head if we say inferior we mean towards the feet let's look at some other directions if we say medial we're saying it's along the center axis of the individual ual right that's medial if we say it's lateral we're going towards the side here if something is proximal we're saying it's at the portion of the limb where it merges with the axial region of the body so the shoulder would be proximal distal would be going down here so the hand would be distal right so the hand would be distal toward to the shoulder sort of a way we would describe it if we say ipsilateral we're talking about two structures that are on the same side of the body so the right hand is ipsilateral to the right foot if we say contralateral we're saying they're on the opposite sides of the body so the right hand is contralateral to the left foot anterior and posterior we talked about those a little bit already uh superficial and deep superficial is sort of on the outer surface of the body so the skin would be superficial deep would be saying we're going into the body more so the heart would be deep to the skin you know something like that so it's very important to know these directional terms when we talk about human anatomy okay if we're making a cut through someone how do we know what plane we're cutting in again very important we're talking about Anatomy if you're going to have a surgery uh or even if you're describing something to your physician so there's three main planes we want to talk about here uh the first plane is something called the sagittal plane or the mid sagittal plane either one's fine and that's if you're taking a uh knife or a scalpel and you're cutting right down the middle of someone's body in terms of uh you'd be separating their Left Eye from their right eye uh so really it's like dividing the left and the right portions of their body right so you're cutting right down the middle of the sternum That's A sagittal plane or A sagittal cut if you're talking about a frontal plane what that is is you're making a cut where you would just have the front portion of someone's body or the anterior portion a transverse plane would be if you're cutting the upper part of the body from the lower part of the body so The Superficial from the in I'm sorry I keep saying superficial the superior right from the inferior and so that would be something that would be a transverse plane or transverse cut so it's important to note these and these are just different sections that result from those cuts I wouldn't worry about those particular um pictures that popped up just now we'll talk about those later in the course the important thing from this slide is that you know the planes okay so what are some highlights of the human body plan uh really we're going to focus on human anatomy throughout this course right and throughout this lecture uh but you want to understand how the human body has evolved and how it relates to other organisms and this can really be seen in the highlights of the human body plan and there's six highlights I want to talk about right here so the first is that the human body can be considered a tube within a tube I say tube within a tube what the heck is that well the first tube is going to be the digestive system the second tube is going to be the outer portion of the body that's what we mean by tube within a tube it's a basic body plan that you see in humans as well as many other org organisms the second is that humans have bilateral symmetry so if you were to make a sagittal cut through an individual the left side of their body looks just like the right side of their body the next one is that humans have a dorsal Hollow nerve cord and by this what we mean is uh you basically have this spinal cord right uh and basically uh as the organ the organism develops or the human develops that becomes that that um dorsal Hollow nerve cord becomes the brain and the spinal cord humans also at least at the embryo stage have a n a not cord and vertebrate and the notocord is something that's a little bit hard to understand because adult humans you don't really see it in it's not very visible uh but the not cord is found in uh all organisms that are considered chordates uh that term cordate is not something we're going to focus on a lot so I wouldn't worry about it but I mention it just so you you hear it uh and the Noto cord is derived from something called the mesoderm it's a type of tissue the Noto cord is always ventral to the nerve cord and what happens is as the human develops so at the embryonic stage you can see the notto cord but as the human develops and becomes an adult human uh what happens is that not cord is replaced by the vertebral column humans also have segmentation what do we mean by segmentation well we mean the human body is composed of repeating units so what are these units well you could see it in the vertebrate right we have repeating vertebrate down the spinal cord also you could see in the ribs right you have repeating ribs that's what we mean by segmentation and then finally humans have ferial pouches and uh again something that's really seen more at the embryonic stage though it does uh yield other structures later on in fish the fenal pouches become the gills okay now humans obviously don't have gills but what these pouches basically lead to later on are uh parts of the inner ear and then also uh certain uh structures like the parathyroid glands uh so so uh humans do have Fingal pouches but they basically uh lead into other structures as the humans develop so why do we talk about this body plan well it gives you a general perspective in terms of uh how we classify the human body you know what qualities it has but also uh what it shows is that if we look at an embryonic human you'll see a lot of these highlights that I mentioned a second ago so look at this embryonic human on the right and you'll notice that it has a lot of similarities to a generalized vertebrate organism and so really when we talk about the human body plan and we reflect upon those highlights what it shows is it shows the unity of life right it shows the unity of life and how uh organisms have evolved from uh from common Origins okay so what functions um uh of the body cavities and the membranes exist in humans so so when we talk about humans we talk about different body cavities and we'll talk about this much more in later lectures and throughout this course but we want to know what is inside each cavity it helps us uh to understand the function of the body as well so for example humans have a cranial cavity it contains the brain uh they have a vertebral cavity it contains the spinal cord thoracic cavity right the hearts and lungs abdominal cavity uh contains digestive organs and then the pelvic cavity uh for part of the urinary system as well as reproductive system so this is an overview on this slide but in later uh lectures we're going to zoom into these cavities and talk about you know what are the anatomical features that are there what organs are there and then what is their physiology you know what is their function on the right hand side of the slide you just see a different view with some of these same cavities mentioned okay so again let's continue this discussion what are the functions of the body body cavities in the membranes well these cavities are classified as something called Cirrus cavities right and they're slitlike spaces surround by something called a cirrus membrane and you might say okay what is the Cirrus membrane well there's basically something called a parietal Sosa and then there's a visceral Sosa and when we talk about this it's basically a double membraned uh structure that has an internal cavity to it and the best way to illustrate this sort of in a schematic way so if you were to take your hand and push it into a balloon that was blown up so you're not popping the balloon but you're pushing your hand into it so it's a very flexible balloon you'll see that the outer portion of the balloon remains intact right so that outer portion would be analogous to something uh called the uh the parietal Sosa right that would be the outer part the inner part of the balloon right that inner membrane where your hand pushed into would be something called uh basically the visceral Sosa and then the space in between those two where you have the air that would be analogous to the cus cavity so that's what we're really talking about when we talk about these cavities where do you find these well they're all over the body here's just one example uh you find them basically in the lungs right so you find them lining the lungs okay so a few more odds and ends before we finish up our lecture here so you might ask yourself a question how do clinicians diagnose disorders right when someone comes in how do they diagnose disorders well they might there's many ways obviously but one thing they might do is they might take a superficial anatomy approach as I mentioned on one of the earlier slides so let's say someone's having abdominal pain they might divide the abdomen right into different quadrants here with with the origin being the belly button this would be the upper right quadrant the upper left quadrant the lower left the lower right remember we talk about the anatomical right right not your right but the anatomical right and so if someone comes in and says o I have this like pain in my upper right quadrant so notice the communication between the patient and the physician we got to know what right is right so if they're saying you know anatomical right we have a pain there The Physician might say ooh what's underneath that and if we look at the schematic we know the liver's there the gallbladder is there perhaps that person's having issues with their gallbladder on the other hand if someone says ooh I have pain in my upper left quadrant of my abdomen then the physician might know if they know their Anatomy which I'm sure they will they might say oo maybe there's something going on with your spleen that we should look at so this is how superficial anatomy can help inform form a discussion between a clinician uh and his or her patient okay so that was our first introdu to the human body remember we talked about an overview of anatomy we talked about something called gross anatomy and also we hit all these different learning objectives so before you proceed to the next lecture if you need to watch this one again I encourage you to do that but make sure you can are able to execute these different learning objectives that you see here if you're able to do that then you know you have a solid understanding of this lecture at this time