Hello anatomists and physiologists, Michelle Glass here and thank you for joining me for our third video in our chapter one video series. And this video is all about human functions and human needs. So let us get started.
When we talk about the functions of the body, We can think about like four major categories of functions for human life. So these four are metabolism, responsiveness, movement, and development. So let's talk just a little bit more about each of these.
When we talk about metabolism, what we're talking about are all of the chemical reactions that occur in the cell. And my abbreviation for reactions is RXN, chemical reactions that occur in the cell. This is what we mean by metabolism.
So then when we are talking about this chemistry, we have to also mention the first law of thermodynamics. that energy cannot be created or destroyed. And so what we see instead is that energy or matter is just going to change forms.
It's transformed. And it's transformed through metabolism. So we have two different categories here of chemical reactions.
We have anabolism, which is where you make something. This is going to require energy. So this is where maybe you have, maybe you have, let's see, I don't have enough room right there.
So let me put up here. You have reactant A and reactant B coming together to make product AB. So that's a super generic way of representing anabolism.
The very opposite of this would be catabolism. Catabolism has that same prefix that we see in catastrophe. So that might help you to remember that a catabolic reaction is a breakdown reaction.
Breakdown reactions are going to release energy. So this is the opposite. You have a component AB and you break it down into its ingredients, A plus B.
And then you're going to get some energy out. So you could add energy on each side here. If I can squeeze it in over there, that works.
That does remind me when we talk about energy for the cell, we're going to be talking about this molecule, which is often referred to as ATP. Let me make it where we can see it better. ATP stands for adenosine.
triphosphate. In our cells, this is basically what we can think of as our energy molecule. So here where we said it requires energy, we're going to, you could make that say ATP.
And over here where we say it's going to give off energy, we're going to say ATP. Okay. And we'll be building on that idea as we progress through the course.
When we talk about responsiveness, what we really mean is that this cell can adjust to both internal and external environmental changes or environmental conditions, or you could just say to the environment, right? That's pretty easy. With movement, we're talking about movement at the cellular level.
So inside of a cell, we're going to see some movement. We can be talking about fluids throughout the body. So we'll see movement in both the cardiovascular and the lymphatic system.
This could be movement at the organ level. So we'll see movement of the heart. We'll see movement of the stomach, small, large, and big.
intestines. We'll see movement in the blood vessels. And this can also be like at the organismal level.
So as you're writing notes, you're moving your body in order to do that. The final function here is talking about development. And notice in parentheses, I've put both growth and reproduction. So development is talking about like all of the changes.
that take place throughout your life. So again, thinking about all the changes that have happened from infancy, toddlerhood, childhood, adolescence, and then do all the stages of adulthood that would be categorized here. We also see kind of in this mix, this term differentiation, which is basically talking about like specializing. specialization.
Okay. And then of course, when we're talking about growth, we mean like an increase in body size. So again, as kids, we're changing quite a lot from infancy into adulthood. And then we typically reach like our mature body height. But that doesn't mean that our body size is not changing.
So any change in body size up or out would all be categorized here. And then reproduction, you know, we talked about in terms of reproductive system, make more humans. So this is where you're getting basically a new generation from parents. Okay, as we continue, we have what we can think of as four requirements of human life.
So these are the things we really need for living. So we need oxygen, gas, we need nutrients, we need a certain range of body temperature, and we also need a certain range of atmospheric pressure. So as we think about our four requirements of life, So when we look at our oxygen levels, if we are without oxygen for five minutes, we're going to get some brain damage. So this is just illustrating the significance of that oxygen.
If you are 10 minutes without oxygen, this is going to be body death, right? So five minutes without oxygen, you're having some brain damage. 10 minutes without oxygen, this is death to your body, right? When we talk about nutrients, this includes water, which is making up about 70% of the adult body mass. This is talking about macro.
nutrients, things we need a lot of. And here we're going to talk about carbohydrates. We're going to talk about lipids.
And we're going to talk about proteins. Now the carbohydrates and the lipids are all about energy. And the protein is all about bodybuilding.
And then we have what we call micronutrients. Remember the prefixes micro means small, macro means large. So macronutrients, macronutrients, the carbohydrates, lipids, and proteins we need on a large scale.
Micronutrients we need on a small scale. And we think about these in our diet as being vitamins and minerals. When we look at temperature, of course, we have an internal body temperature for humans of 37 degrees Celsius or 98.6 degrees Fahrenheit.
Now, these are our textbook classifications, but it's important to remember as we study humans that, you know, in 2021, there are 7.9 billion humans on the planet. So there's probably 7.9 billion. um different steady body temperatures and when we look at the average for humans we see it's 37 degrees celsius or 98.6 degrees fahrenheit so all these factors that we talk about there's a little bit of fluctuation that exists um here in this idea now the reason that these temperatures are important is we'll see that our chemical reactions it's chemical reactions you have a very important optimal range of where they work. And it's connected in with this special molecule that we'll talk about in our next chapter, which is called the enzyme.
So we'll make this connection in the future. And then when we're talking about atmospheric pressure, this is important because it's keeping blood glasses, blood gases. is dissolved.
This is important because of our pulmonary ventilation or what we're going to just think of as breathing. So that actual ability to get air from the atmosphere into the lungs and from the lungs out back into the atmosphere, this is connected in with a relationship between the atmospheric pressure and the pressure inside of our lungs. And also just, this is involved with all of our body fluids. In both of these cases, these last two features, there's an example in the text on decompression sickness. That really helps to illustrate the significance of atmospheric pressure.
And in talking about the temperature, we see that in medicine, we can kind of manipulate body temperature to help with things such as open heart surgery. So you will find it interesting to read about controlled hypothermia. All right, that's it for this video.
Stay tuned for our next video. on homeostasis. I know you've been dying to learn more about that.
And as always, take care of yourselves and each other.