This is really just an introductory video. We'll go into more depth in subsequent videos

talking about specific systems. But in this video I want to kind of define anatomy and

physiology. Talk about some of the major themes that we'll find. And then we'll get into tissues

and just a preview of all the different organ systems. Before we get there though I want

to talk about this over here. This is an adjustable spanner. I always thought this was a crescent

wrench but a specific type of adjustable spanner apparently is a crescent wrench. So think

for just a second about what are some of the structures on the wrench. Well right here

we have this moveable metal. We've got a rolling device. We've got teeth. Got this long arm.

So these are all structures. But what do they do? Well you know this. That I can roll this

back and forth. This will move this in this direction. So I can fit different nuts. I've

got a huge amount of leverage by pushing on this. And so basically what we've identified

is the anatomy and the physiology of this tool. In other words, anatomy is simply what

it is. What's the structure. Physiology is the function. And so let's quit talking about

tools and talk about the human hand. And so there's a term that goes by form fits function.

And so the form, think of that as the anatomy. So the form of my had, the muscles, the bones,

the tendons, and all of that is going to be the form. What it does, how it works, how

it operates, all of those things are going to be the function of the hand and how they

work. All the way from the nerves that pick up touch to the muscles. All of that is going

to be the function. And so in the back of your head always be thinking form fits function.

Anatomy fits physiology. Okay. So basically there are a few themes in anatomy and physiology.

The first one is called homeostasis. And you may think of just like a home. Homeostasis

means maintaining a stable interval environment. And so how do we do that? Inside our home

we use a thermostat. And so a thermostat is basically going to use a feedback loop. It's

going to use a negative feedback loop. If the temperature gets too high it's going to

turn off the heat. If it gets too low it's going to turn on the heat. And so it's going

to keep you at a stable internal environment. Now what about inside our body? We have the

same thing. We have a thermostat. It's the hypothalamus, which is right above the roof

of your mouth. And it basically is going to sense the temperature inside you. It's going

to be right around 37 degrees celsius. What happens if your temperature goes too high?

Then your body is going to react. It's going to start to sweat and you're also going to

start to vasodialate. You're going to open up the capillaries near the surface so you

can carry that heat away. What happens now is our temperature is going to be depressed.

If it goes too low, what do we do? Well we could get goose bumps. Those are creepy looking

goose bumps or we could vasoconstrict. Hold that body heat near the body and constrict

movement through the capillaries and our body temperature is going to increase. This is

a negative feedback loop, but it's a great example of homeostasis. And in anatomy and

physiology we're going to have to learn a number of these different feedback loops.

Another thing that is important is hierarchy. In other words, in a house you've got a kitchen.

In that kitchen you've got a sink. In that sink we've got a drain. So we've got parts

that make up that whole of the house. And same thing inside biology. We start at the

level of atom which comes together to form molecules, macromolecules, organelles, cells,

tissues, organs, organ systems. But not all of this is anatomy and physiology. Anatomy

and physiology really begins at the level of the cells, tissues, organs and organ systems.

And so this is kind of going to be our anatomy and physiology area. I'll spend a lot of time

here on organs, tissues and organ systems. As we get more up here this gets more into

the ecology. So we won't spend a lot of time up there. But basically this is what we're

doing. So there is a hierarchy. And each time we go up to a bigger classification or a higher

level of hierarchy, we're going to have emergent properties that start to show up. Another

thing that you should understand is that those cells then form what are called tissues. And

you should have a good understanding of the different types of tissues. There are only

four in humans. And those are epithelial, muscle, nervous and then connective tissue.

Let's start with epithelial tissue. Epithelial tissue, there are basically two things that

epithelial tissues have. First of all I should not get too far ahead of myself. Epithelial

is going to be the linings of our organs. But it's also going to be the outside of our

body. So my skin, what you're looking at is epithelial tissue. And so we classify epithelial

tissue according to its shape and then the number of layers. And so there are a few weird

terms. First one is weird. And that is if we have flat epithelial tissue we call that

squamous. So this would be squamous cells. Next, if it looks like this we call that cuboidal,

because it's like a cube. And then finally if it's look like this then we call that columnar.

Because it looks like a column. And so these are the three different shapes. Pay attention.

Because I'm going to test you on the next page. And then the layering. If it's a simple

layer we call that simple. If it's just one layer of epithelial cells. But if it's a number

of layers then we're going to call that stratified epithelial cells. So let's look at some epithelial

cells. What they might look like. So basically these are all epithelial cells. They're going

to be the lining of organs or the outside of the body. So if we look at this one right

here, that would be simple squamous. Right. They're flat and there's a single layer. So

like the alveoli in your lungs could be an example of simple squamous cells. What about

this one over here? As I pause awkwardly for you to answer? That's right. That would be

simple columnar. What about this one? Simple cuboidal. Right. This would be like the lining

of the nephron of some of the glands in your body. What about this? That's right. Stratified

cuboidal. What about this? That's stratified squamous. Yeah. That's what your skin is.

You're constantly loosing that, but it offers protection. And then this is a tricky one

here. I don't think you could answer that unless you've been looking ahead. These are

actually pseudostratified columnar. They're pseudostratifeid. They look like they're stratified

but that's because some of them are fat at the bottom and skinny at the top. And some

are skinny at the bottom and fat at the top. And so there are some of these in your lungs

that actually have cilia on it. And so we would call those, let me see if I can get

this right, psuedostratified ciliated columnar epithelial cells. And so if you learn some

of these terms you're going to do well. And you're also going to impress people with all

of your big terms. Next it gets a little easier. We've got the muscle cells. Muscle cells are

responsible for motion. There are three types of muscle cells. Those are going to be skeletal

muscle cells. This would be an example of skeletal muscle cells right over here. That's

going to move my finger. Move my arms. All movement in my body that I'm in control of

is going to be skeletal muscle. We also have smooth muscle. Smooth muscle is not going

to be as regular as this. Example of smooth muscle are going to be involuntary muscles.

So the movement of food down your esophagus becomes smooth muscle. Or the movement of

food all the way through your digestive system is going to be smooth muscle. I don't have

to think, "Oh, I want to move food" specifically through a certain part of my small intestine.

It just moves on its own. That's smooth muscle. And then the third type we have, it's only

found in the heart is going to be cardiac muscle. It actually looks a lot like the skeletal

or striated muscle, but it's going to have these little intercalated discs inside it.

And that's going to transmit electrical signals so they can move through. Because the electrical

signals of the heart are going to create the contraction of the heart. Next we've got the

nervous tissue. Nervous tissue is going to send quick signals through out your body.

It's basically made up of neurons and then some glial cells that will help out with that.

But basically what you have are all of these dendrites on this side. They're going to sense

a signal. They're going to send an action potential down an axon to another nervous

signal or another neuron. So that's basically what you're doing right now in your brain.

Nervous tissues. The nerves through out your body are going to be nervous tissue. So basically

what do we have so far? We've got epithelial, covering. We've got muscle, movement. We've

got nervous. So what's left? Last thing is going to be connective tissue. And so connective

tissue is going to be kind of a catch all. It's going to be everything that we haven't

talked about so far. And there's a lot of things that make up connective tissue. Connective

tissue is going to have, basically it's going to have living cells, but it's also going

to have non living matrix around it sometimes. And so two examples would be loose connective

and dense connective. So basically if I pull my skin up like that, and let it go, what's

holding it there is loose connective tissue. So inside there we're going to have some collagen

fibers which make it so I can't pull my skin off my hand. But we also have these elastin

fibers that are going to bounce it right back. And then the more collagen that we have, the

more dense it becomes. So if we were to grab a tendon, for example, that's going to be

a type of connective tissue. But it's going to have way more collagen in it. It's not

going to be quite as bouncy. So other types of connective tissue would be like cartilage,

blood, bone, fat. These are all connective tissue. All of these things connect the other

types of tissues. And so again, there are only four different types of tissues inside

our body. And then the final thing I want to leave you with is kind of a preview of

where we're headed. The different systems inside your body. And basically what they

do. If we start with digestive systems, basically the job of that is to digest food and then

absorb that food into our circulatory system. Starts with the mouth. It actually starts

with your eyes when you see some food that you really want to eat. Next we have circulatory

system. That's going to move blood and thereby oxygen, carbon dioxide, nutrients around in

your body. Respiratory system. Here's those alveoli I was talking about a second ago.

Basically taking in oxygen. Getting rid of carbon dioxide. The immune or lymphatic system

is going to be made up of a bunch of lymph vessels. So that's going to, basically going

to take in plasma or liquid that's leaked out of your circulatory system. Return it

to the circulatory system. But we also have these lymph nodes. And basically those are

areas where white blood cells will sit. And they are able to fight infection. Next we

have the excretory system. It's a way to get rid of nitrogenous waste. But it also serves

the function of regulating osmolarity in our blood. So the kidneys are a big part of the

excretory system. We then have the endocrine system. These are going to be all of the glands

inside your body and the hormones that they give off. From the pituitary all the way to

the ovaries and the testes. Next we have the reproductive system. Basically different in

males and females. But a way to produce offspring. Nervous system is again those nerves connecting

from the brain to the peripheral nervous system and back again. So we can respond to our environment.

Integumentary system is going to be the skin, the nails the hair. Basically covers our body.

Skeletal system is going to give us support. But it's also going to store important materials

inside our body. Then finally we have the musculatory system which connects, using those

tendons, the dense connective tissue to the bones and allows us movement. And so those

are the organ systems. That's anatomy and physiology. Again we'll get into more detail

with each of these. But if you can remember those themes, and the idea that structure

fits function you're going to do just fine.