Welcome to the first lecture in introductory human physiology.
And today we want to talk about homeostasis, this is the, this is the
basic theme for physiology. All of the organ systems are going to
integrate in order to maintain homeostasis of the body, and the
homeostasis of the body is to maintain conditions within the body that are
compatible with the life of the cells. So, the things that we want to look at
today, the learning objectives are first to explain the basic organization of the
body, secondly we want to define the fluid compartments of the body.
Third, explain how solutes such as sodium chloride, glucose and so forth distribute
within the body. And fourth, we want to explain what
homeostasis is and the homeostatic mechanisms that regulate this, we're
going to deal with in the very next lecture, which is coming right up next.
And then last, we're going to very quickly talk about mass balance and how
the body maintains mass balance. Alright, so the first thing that we
want to consider then, is the body components.
So, as you all know the body starts with this, with, a human body starts with a
single fertilized egg and this egg then undergoes divisions to, to make multiple
copies as well as differentiation. The differentiation allows the specific
cells to acquire specialized functions. These functions then, this groups of
cells that have the same specialized function, will work together to form what
are called tissues. We have four tissue types within the
body, they are muscle, nervous tissue, connective tissue and epithelium.
These four tissue types will form the organs and, and the organs will work
together as, to, to perform a specific function for the body and then, at that
point if we have more than [INAUDIBLE] one more organ functioning.
That is, we have several organs functioning together, then they're called
an organ system. So, for instance an organ system would
be, an organ would be the kidney and the organ system, the renal system or the
urinary system would be the kidney with the two ureters.
That are taking the urine that's generated from the kidneys down to the
bladder, where the urine can be stored in the bladder and then eventually expelled
to the outside of the body, through what is called the urethra.
So, that's our, our urinary system. So, the the organ systems that we're
going to consider, there are ten organ systems in the body, we're going to
consider nine of them. and they are going to perform very
specific functions. So, for instance, the skin, the skin is
the largest organ of your body. It has, its specific function is
protective, so it forms a barrier of tissue to the outside world, it keeps all
of the inside materials, sort of, organized.
The skin is a, is a very important barrier for the loss of water.
So, it's a hydrophobic barrier, so it allows the body to maintain water even
though we have conditions, where we would normally become dehydrated.
