um we're going to take a look at the chemical level first so the chemical level see if I can get this to cooperate without tipping I've never tipped the iPad in class but that's coming I know it's coming just a minute before I do tip it uh that would be dramatic though I'm probably very memorable so let's talk about the chemical level and then we will visualize it so we look at the chemical level let's talk about atoms and molecules let's talk about what is the between elements substances compounds for example there's a lot of differences chemistry and Physiology are so intertwined when we talk about the human body in health and disease that hopefully you're starting to see the benefit of taking all those chemistry courses so when we think about things like compounds like water um some of them are really really prevalent in the body and some of them are less prevalent in the body like Cobalt for example so we're going to start to see how all these chemical levels work together so first of all chemical level let's take a look at some things in the human body that we need to be aware of elements versus compounds if I had to guess you've been introduced to these probably like what Junior High maybe but it's worth revisiting because on this particular piece of paper in front of us are some really interesting things that might look a little different we put them in a physiological perspective elements pure substances all Iron atoms for example that's an element sometimes elements though could be several atoms put together like molecular oxygen O2 iron where do you get that fromed meat red meat where else leafy greens yeah or legumes beans for example so lots of different ways we could get iron the diet why do we need iron why do we need the seemingly simple elements what do we use it for get it from the diet we hope we can absorb it is iron easy to absorb no iron is squirly it is hard to absorb so that's one barrier let's say we get it into circulation what do we do with it iron where do we find it hemoglobin somebody said it yeah so iron is a huge part of hemoglobin and hemoglobin helps you carry oxygen in red blood cells or arthra sites can you store iron in the body really important element here it is you came and that's with a protein called fertin and a lot of people that have low blood iron don't have a diet problem and they don't have an absorption problem they have a fertin problem fertin is a protein that stores iron in in most cells so even something so simple like iron take for granted so difficult for some people to get enough of and without enough iron you're going to have a hard time oxygenating your cells and tissues because iron is part of hemoglobin and that's what carries oxygen in the body one seemingly simple element can lead to so many different problems so don't take these things for GR oxygen molecular oxygen we don't deal with atomic oxygen great name for a band but probably not so great for cells molecular oxygen O2 why does oxygen exist this way for us in the atmosphere what is it about oxygen that doesn't like to be by itself why O2 and not Atomic oxygen just o chemistry people why did these two things go together oxygen and oxygen put it together their oxygen their electrons oxygen is a squirly little thing oxygen does not have all eight electrons in its outer bance and so it's going to be electron breed and that can work for us and that can work against us oxygen exists as molecular oxygen because it shares electrons with another oxygen atom O2 oxygen was not something that life could typically deal with long ago so I'm going to take us on a trip back three and a half billion years ago Earth Earth formed about four bilon billion years ago about three and a half billion years ago first life forms and it is not capable of interacting with oxygen and there wasn't a lot of oxygen then because plants hadn't been invented anyway life at that point was Anor robic couldn't handle oxygen that was limiting because without oxygen you can't create a lot of ATP and if you're going to sustain a large organism like ourselves you need a lot of ATP being able to handle oxygen and not die in the process was a huge step forward in life what is it about oxygen it's so difficult to handle molecular oxygen you breathe it in it's 21% of the atmosphere all over the Earth and yet it will kill your cells it is toxic why is that what does oxygen produce when you use it in your cells free radicals great job free radicals and free radicals will destroy cells or membranes or cellular components so that cell quickly would be taken off the face of the Earth one huge adaptation a huge advancement for life in general was the ability to handle the free radicals that are produced by oxygen your cells do this effortlessly by producing enzymes that look for these free radicals and say I don't think so not today and so it will destroy those free radicals before they can destroy you as a backup though because I'd like to think humans are as a species overachievers we said you know what sometimes three radicals get away they escape these enzymes and we still need to handle oxygen and we don't want ourselves to die with these three radicals we're going to have a backup plant and that came in the form of being able to use nutrients like vitamin E Vitamin B and beta keres to scavenge the extra free radicals so we're overachievers all that to say oxygen this thing that you're really aware of that you can easily say shares electrons which is why it's a molecule was a huge turning point in the evolution of life and our ability to survive get big grow move around a lot Power this huge thing called the brain is this a Sor thing called oxygen inil to handle it moving on to compounds we can put stuff together and make a compound so for example maybe we're going to make water H2O H2O can also kill you but we hope it does not so compounds just different atoms put together so just a quick trip through some chemistry you'll hear me say these words quite a bit in this class and I just like to level the playing field some people have had chemistry lately some of you it's been a while so hopefully just a little jog of the memory is all it takes when we look at the most common elements in the body we see these become very prevalent oxygen carbon hydrogen nitrogen and calcium phosphorus sort of on the end there 99% of the elements in the human body are these six if you were to buy these elements on the free market how much do you think it would cost to build a human body out of these pure elements it's not going to make you feel too good no it's $357 that's how much it would cost to build a human body with these elements raw elements not put together in a working form but raw elements if you went to buy those that's what it would take to build a human body pretty sad huh $357 interesting stuff though so it turns out it's not just the elements that we're made of it's our ability to put them together and use them and that's when we get expensive so let's talk about the next level of organization so most basic form we're looking at obviously elements m ules compounds but let's start to move this into something a little bit more physiological and we're going to take a look at the cellular level stuff you probably expected me to start with but cells are made of elements and require elements and interact with elements so we have to have some background there talk about the cellular level of Life cells are the smallest unit of life smallest unit of life you can't go any smaller than a cell and still call it a living unit what is required three things required for us to say these things must be present in order for something to be considered alive what are they what's required to be considered a lie what's that they can take in and metabolize nutrients that's great I'll take that so they can take in and metabolize nutrients homeostasis homeostasis is not requirements for life at the cell level organism level yes yeah be able to self reproduce oh they got to be able to reproduce yep reproduce on their own and one more it's it's obvious and people Overlook the obvious re not bad not quite though it's genetic material got to have some sort of genetic material so DNA or RNA so I'm just going to wrap that up with genetic material these are the things that a unit must have all three in order to to be considered living so with that let me ask you a question are viruses alive they are not what are they missing two two of the three they can't take in nutrients or metabolize them on their own and they cannot reproducing their own they do contain genetic material that's why they infect your cells they get into your cells and then you do this for them really smart isn't it like nature is not dumb so they are not technically alive so viruses are not living but cells are cells of the smallest unit of life let's talk about what that means to be alive feel like this is rather rather um like metaphorical metaphysical almost it's not meant to be but we need to interact with elements so those elements that we just talked about we're going to see them make an appearance here here we have a cell it's pretty basic cell it's got a phospholipid Bayer for a membrane no surprise there it's got a nucleus it's just a typical cell and it is ryant upon other things to survive so I'm going to bring in a capillary a little tiny blood vessel and all cells are served by capillaries within like 10 micrometers in a capillary cells beyond that really don't survive they have to have a constant input of blood because they get elements from that blood and they got to have those to survive they don't exist in a vacuum so when we think about this cell so obviously nucleus POS B layer bringing in some blood supply so cells are comprised of elements they don't live in a vacuum where do those elements come from thinking big picture where do we get things like iron we've already talked about the diet we get oxygen from the atmosphere so it turns out where do these elements or compounds come from you could say diets or environments so that's sort of big picture how do we get them to cells though well they got to have a blood supply so you can't just live in a nutrient-rich environment you have to be able to take those nutrients in and circulate them with the blood and so here we're already sort of making the leap between what does it take to be alive and how cells actually do this so there's a couple ways cells can interact with the blood to get what they need so sort of moving down here if I was to I'm going to keep this pretty simple I'm going to give you a molecule and I'm going to give you a compound one of those molecules is going to be oxygen since I've already talked about that and then I'm going to give you a compound and that's going to be a really important compound in this class and for just Health in general and that's going to be glucose glucose is a big big mole molecule big compound how is this cell going to attain these two really basic yet fundamentally required things let's talk about oxygen how do we get oxygen from the capillary and into the cell what process would we use how does cells get oxygen from the blood take a deep breath in and ponder that so the funny thing is when I ask you these questions like it's happening in your body I'm like look within cell respiration that we use oxygen but how are we going to get it from the blood diffusion diffusion what kind of diffusion kind of diffusion is oxygen a big molecule no is it polar no so what kind of diffusion it rhymes with diple simp simple yeah good simple um simple diffusion so it turns out some things are really easy to attain Like Oxygen we can just get that from the blood right through a little bit of extracellular fluid across that fossil B layer simple diffusion so I'm going to go ahead and populate that down here simple diffusion that's not an option for many things cells wish it was we can move oxygen carbon dioxide should you encounter a large amount of nitrogen gas you can move that that way hope you don't but you could not a lot of things can move via simple diffusion only things are really small and or nonpolar most things that a cell needs like glucose not simple diffusion why why not what's wrong with glucose why can't it do simple diffusion it's big yeah C6 h206 that's a that's a big molecule what are you going to have used to get glucose across that cell membrane from the blood could be a transport protein could be a a process called it's not simple diffusion but it's cousin brother a facilitated diffusion facilitated diffusion you're going have to use some sort of protein to facilitate the diffusion of this molecule from the blood into the cell so a lot of things cells need compounds for example are too big and or polar and they're going to require a little protein in that cell membrane to get in that makes them inherently more difficult to deal with because that cell has to produce the protein in its membrane to get that thing in we also are relying up upon concentration gradients so we hope the blood has enough glucose to supply the cells so when we look at things things like that we're going to call it facilitated diffusion what about water cells need a lot of water they can make some water metabolic body water but what if we had some water over here cell would really like that how are we going to get that into the cell what's the process called where we move water across the cell membran osmosis yeah osmosis so osmosis is really just the diffusion of water but I'm going to put that on our list as well osmosis is the movement of water and sometimes that can be through simple diffusion those water molecules just swirl right through that phosph b layer because water is small it is polar but it's small so it has that option but the majority of cells are going to get the vast majority of their water using a protein called what back to chemistry has a cool name it's called an aquapon you ever heard of an aquapon these are proteins produced by cells and they're specific for water and they let a large amount of water into out of the cell turns out cells can't get enough water through osmosis alone they have to use these aquapon to stay hydrated so aquapon proteins in a cell membrane that allow facilitated diffusion of water so here are some ways that we can take the information seemingly simple elements and compounds and apply them to a physiological purpose we can also turn this right around and understand the mechanics of diabetes diabetes up until Co came along was like the third leading cause of death in this country globally probably for developed Nations up here we actually have the premise for what happens when a person has diabetes so if this cell can't do this and a person continues to eat carbohydrates has a lot of sugar in it what happens to blood glucose levels they go up and then the cells can't use it and the person continues to take in glucose what happens to blood glucose level they go up and they go up and they go up you have at the heart of diabetes a broken facilitated diffusion problem that's what diabetes is it is a broken facilitated diffusion problem you have too much blood glucose and you can't get it into the cells which need to be the sink for glucose you can try treating it with insulin you can try treating it with uh things like o but at the heart of all that you have a broken facilitated diffusion problem and understanding it at that level makes you a much better scientist whatever field you're going into and it makes you more likely and more open to new Solutions because you're not stuck in the same rep you're like wait wait wait I understand that's how this drug works but at the heart of this we still have a broken facilitated diffusion problem that's the benefit of truly understanding this stuff at the foundational level and not just taking it for granted on the surface you can do a lot more with it in the future questions before I continue on our tour of life in the metaphysical tent called acur 120 so far so good let's step up a little bit I'm going to continue to block this off I don't like how I arrange this particular set of notes because it makes it hard to present so note to self change that I'm talk about tissue level tissue level tissue level of organization stepping up a little bit in complexity tissues are defined as groups of cells working together I'm sure you've seen that before groups of cells working together the body has this is astounding and even more astounding somebody was tasked with figuring this out I feel like some poor grad student somewhere had to do this um the body has 30 to 40 trillion cells T capital t is trillion that's a lot of cells 30 to 40 trillion 30 to 40 trillion cells and yet all those cells are organized into just four primary tissues four primary tissue types which kind of makes it nice because it's a lot easy to get your head around every cell in the body belongs to just one of these four categories they're Mutual exclusive they cannot belong to both or three that would be weird so these are fundamentally set during embrionic development this cell will become that part of a tissue that's kind of non-negotiable let's talk about the primary tissue types there are four they're going to make an appearance in this class A lot as well the first that we're going to see epithelial epithelial tissue is everywhere epithelial one of the four primary tissue types it makes up things like the skin so that's pretty much a no-brainer but it also makes up glands exocrine glands those are epithelial endocrine glands or in epithelial tissue in nature the lining of blood vessels that's epithelial tissue the surface of the heart that's epithelial tissue so it turns out it's way more than just skin we find it everywhere but wherever we find it it kind of does the same thing so that's nice because once we know it's epithelial tissue we can make some pretty fair assumptions about what it's doing there and you start to see well that means if it's doing this and it's liable to for this pathology this disease or if it breaks then we'll probably have these problems and then you can start really being able to predict what might happen the second primary tissue type something called connective tissue which is always abbreviated CT connective tissue CT is the only one that gets an abbreviation connective tissue CT it is some of the things you might think about with connective tissue um ligaments and tendons you know like this sort of the fibrous stuff that connects the body that makes sense connected tissue but it's also going to be found in bones bones are technically connective tissue as is blood blood is a connective tissue because it connects different parts of the body it's found in fat white and brown fat are both types of conect Ive tissue so it's a strange category it's interesting third type we'll see it quite a bit this semester muscle that would be skeletal muscle cardiac muscle or smooth muscle it's probably the most familiar to you it is the easiest to understand it's very straightforward as far as the primary tissue types go and then our fourth one not so simple nervous tissue nervous tissue those are the four primary tissue types so 30 to 40 trillion cells in your body and yet they're all categorized into these primary tissue types and they all share similar characteristics wherever we may find them in the body they have a lot of similarities so let's take a look at the benefit of tissues like why are we even talking about this are there benefits provided by tissues that are above and beyond that which is provided by cells and the answer of course is yes so here I have some cells I'm going to be working together right now they're pretty nondescript cells as cells tend to be if you isolate them benefits provided by cells working together what do we think benefits provided by above and beyond the cell in its own little L benefits could be provided these are all the same cells same type of cells but now they're working together what benefits provided yeah what's that sh resources I'm not sure can you be more specific what are they going to share I don't know it could be I I'm always questioning these things too what else do we think benefits protective what's that protective Blair in this case yes because I am going to move into epithelial tissue so yes you've read my mind this will become epithelial tissue and it will form a barrier what if this was nervous tissue or skeletal muscle you can move you can move but what benefit is provided by tissues it's not provided by cells alone provide functions more functions it's all more functions whatever that may be they can just do more it's sort of like a metaphor for life right like work together you can do more so it turns out benefits provided by cells working together they can just accomplish more and so someone said epithelial tissue provide a barrier I like that that's what this is going to be if this was a single epithelial cell up here it's really busy just trying to stay alive get water get glucose get oxygen give up some waste products it doesn't really have the ability right now plus it's super small to do things like protection so if this was a group of epithelial tissues or epithelial cells making up a tissue called epithelium well now we have something much more sophisticated one of these cells doesn't have to do everything it could do a lot so epithelial cells that's what I've sort of bracketed here I have quite a few of them we put them together we make a tissue called epithelium and now all of a sudden we can do a lot more like form a barrier we could keep out things like germs or pathogens bad bugs that want to try to infect us it's a lot harder to get through many cell layers than just one we could also with this barrier prevent the loss of water because right below the skin surface for example we have blood vessels and they have a lot of water that effective tissue barrier now prevents the loss of water so one cell could not do this on its own many cells working together now we're starting to get a lot more sophisticated features we're starting to become functional organ which is what we're going to move into so we can do a lot more let's step into our next bit of uh organization here organ level organs are formed from two or more tissue types two or more tissue types structurally form a functional unit and this is going to be above and beyond what that one tissue could have done on its own I'm going to be sticking with skin it's the first organ system that we really look at in here so at the organ level there are about 78 main organs some people say 79 so this little Squigly thing here is sort of Shand for about 78 organs so we're going to see how these main organs in the body form from two or more primary tissue types what benefit they could provide and again I'm going to stick with skin since we're sort of talking about epithelial tissue or we were we're going to introduce another see how these primary tissue types work together let's take a look at this over here we've got kind of the basic blueprint for skin or lining of the digestive tract or lining of the respiratory tract we're going to see here benefits provided by tissues working together we're going to accomplish crucial body functions accomplish crucial functions for life things the body depends on to stay alive up here we have some epithelial tissue our little epithelial cells still working together as epithelial tissue that hasn't changed I just squashed them and I brought them down right below that though we would find things like connective tissue connective tissue it turns out the skin is formed just like this the epithelial barrier alone is good for keeping pathogens out preventing water loss but it doesn't have a lot function beyond that it's a barrier and that's really what epithelial tissue does provides a barrier it's really good at that but if we added some connective tissue right below it we could do so much more so now we're going to start to build a little bit more of an organ that connective tissue houses a awful lot of things that we would never see in epithelial tissue we put them together and we get some really amazing features for example connective tissue is usually highly vascularized I'm going to draw in some little blood vessels here highly vascularized a lot of capillaries or just simply blood connect tissue also houses a lot of glands like exocrine glands exocrine glands produce products that are secreted to the outside surface maybe that outside surface is going to be the surface of the stomach where you're going to digest your food so in this connective tissue we may also have glands with ducts and glands can have a variety of shapes and sizes but they're still housed in connective tissue glands so now we've got two very different tissues epithelia on the top connective tissue on the bottom you put those together and you have a lot of function a lot of sophistication we can protect the stuff underneath our epithelial boundary protects its glands and the delicate blood supply prevents pathogens from into that blood which would cause sepsis and now we can house things down here that are well protected and they can secrete to the surface if this was the lining of the stomach which is lined with epithelial tissue and connective tissue we could produce some enzymes here some exocrine products that are pretty acidic and we could secrete them to the surface because we have this nice epithelial boundary that acidic secretion would digest our food for us but stuff underneath now we've got something really functional that we could really do something quite amazing with that we could not do with these tissues on their own so they each have their purpose put them together and you get just sort of an explosion of function let's take a look at organ system organ system actually gets a little bit simpler when we get to the organ system as you might have guessed two or more organs working together that's what an organ system is takes two or more organs working together two or more organs working together major body function is what we get from this there are 11 different organ systems in the human body fully formed human body that's quite a bit and they don't have to just be part of one organ system you can have an organ that's part of several different organ systems so this weird thing that humans like to do which is categorize things and not let them out of their box because it's easier for us will lead us astray so an organ could belong to two or more body systems organ systems an example so I'm going to say could be tricky and by that I mean an example would be the pancreas it belongs to two body systems what do you think those might be what does a pancreas do dig system digestive system there's one pancreas makes a lot of digestive enzymes and it secretes those to the small intestine so it's firmly part of the digestive system but the pancreas also secret some something called insulin insulin is a hormone so what body system does a pancreas also belong to with that piece of information endocrine so it's complicated so we can't just take an organ and say oh it's part of this system and if this organ has a problem only this system would be impacted that is not true they usually pretty Tangled Up but we can talk about them in organ systems just don't be led astray to think they're nice discreet packets because they rarely are let's talk about the benefit of an organ system above and beyond tissues are just organs benefits provided by organs working together so I'm going to go with the stomach the digestive system I'm going to use that as an example because I think it's something we're all familiar with pretty straightforward if we looked at an example like the digestive system it's made of many organs all the way oral cavity all the way through to the large colon large intestine that's a lot of organs and you've got some accessory organs like pancreas liver gallbladder fit several different categories but they could be part of the digestive system with those organs collectively doing an accomplished function we could do a lot so for example we could with all these different organs take in nutrients you could break them down you could break them down mechanically or enzymatically and then you can absorb the nutrients so here is an example of why an organ system is able to accomplish more it just has more features more ability downside is if you lose one of these organs probably going to have multiple systems that are impacted pancreas liver w super important now let's get to this organism that we call the human so what can you say about the human at this point I'm going to introduce a term to you called the bow plant that is German a lot of science terms are Greek or Latin but this one's German the bow plan you'll see this written in physiology it just means body plan but if you see this in the future that's what it means it's German for body PL if we talked about this whole body plan organism of the human we can say several things about the plan we could call it a tube within a tube construction have you heard that before tube within a tube construction the reason we say that is because one of the first things that forms in the human body during fetal development is the gut tube the GI tract it will become the GI tract but from this gut tube that's sort of the basic plan and that does serve as the tube around which our tubular body is built so tube within a GI tract forms really early and from that we get the formation of other organs strange things happen during fetal development parts of the pituitary gland you've heard of the pituitary gland before located in the brain it forms from the oral cavity it's a strange Twisted thing that happens during fetal development so gut tube first and then lots of other things form out from that we could say the b humans are bilaterally metrical if you take a mid sagittal plane right down the middle cut it we should be more or less equal halves more or less equal halves on the surface that would not pertain to the organs they're not bilaterally symmetrical but the body plan in general is we are bipedal what does that mean walk on two legs walk on two legs and of course we are true homeotherms and that changed so much about our physiology when we became that way what does that mean true homeotherm dissect that word homeotherm look at it's prefix homeo what does that mean same therm temperature we maintain a relatively consistent internal temperature that changed a lot about our body plan to be true homeotherms the old term is endotherm you might have heard endotherm and ectotherm those terms are kind of falling into a favor because they're not descript true homeotherms birds and mammals are true homeotherms to become a true homeotherm we had to do a couple different things and this was a huge change shift in our Evolution and really the future of what we become first of all we had to be able to support a really high metabolic rate because keeping a constant temperature takes a lot of energy if you're too hot or too cold you're going to use a lot of energy to maintain that 37° body temperature 98.6 so we had to have a lot of high metabolic rates and the ability to support a high metabolic rate required really changes in two things lungs and heart take in oxygen and pump that oxygen around so that was a huge change that one evolutionary Trend to become a true homeotherm changed everything for us and we never look back from that we got a four chambered heart most vertebrates don't have a four chambered heart turtles have three chambers fish have two Chambers birds and mammals have a four chambered heart to support our metabolic rate we had this huge thoracic cavity that was devoted more or less to lungs so that we could support this High metabolic rate and then thousands of miles of blood vessels to pump all that oxygen and nutrients to the cells that require them so with that since I'm almost out of time and I do not keep people late I hate when that's done to me here's some things I'd like you to think about there are some questions at the bottom you already have this you don't need to write it down I would invite you to give these some thought outside of class sometimes these appear in quizzes sometimes these appear in exams and sometimes we're just going to talk about them the next day but it's a good way to check in with yourself do I understand this and feel comfortable with that I'll see you on Thursday we'll get into our next set of notes let me know if you have any questions about anything