BIO156 online / summer – Chapter 14 (part B): organ systems

BIO156 online / summer – Chapter 14 (part B): organ systems


Hello! On this next section of this chapter we will
briefly talk about organ systems. Remember, organs were made of tissues, and
when a group of organs worked together for a same function – they made an organ system. So, human (which is an organism) is made of
a number of organ systems. And, we will go through these organ systems, but, as we go, we will classify them into
these five groups. They can be either involved with: transporting
fluids though the body, body maintenance processes, controlling various systems, collecting information
from sensory organs, processing info and passing motor commands to be executed, or reproduction. So, the first one that we are looking at is
cardiovascular system. It is made of: the heart, blood vessels and
the blood in them. That is definitely part of the transport systems;
we transport oxygen from the lungs to the tissues, nutrients from the digestive system
to the tissues, and waste products and carbon dioxide from the tissues to lungs and to be
eliminated through various other routes, too. The reason why cardiovascular system is so
important is that, really, nearly all cells in the body are more or less surrounded by
tissue fluid. And, we know that if your heart stops beating,
we must get the cardiovascular system going, even artificially, really fast. In this case CPR aims to keep pumping at least
some of that blood throughout the body. So, clearly cardiovascular system is an important
one. The next ones, that also belong to the transport
systems, that I want to mention are lymphatic and immune systems. So, lymphatic system is made of the lymphatic
vessels – which are, almost like, a drainage system that is complimentary to that of a
cardiovascular system. In addition, it included lymph nodes and a
number of lymphatic organs. In addition to collecting the excess tissue
fluid that might leak out from the cardiovascular system, it has an important (but often less
known) purpose of carrying fat molecules that are too large to be absorbed directly from
the digestive system. Immune system, instead, is especially important
in defending against diseases and foreign invaders that may enter your body. And, as with the other systems, you will talk
more about this on your other biology classes as you progress ahead. The next ones that I want to talk about are
all about maintenance of the body. They add substances to the blood, or remove
substances from it. And, the first one that I want to highlight
is respiratory system. So, this includes the lungs and all the tubing
that helps to transport air in and out of them. Really, the main purpose of this system is
to bring oxygen into the body, and remove carbon dioxide from it. And, this all happens at the level of small
air sacks at the lungs. Okay, another important maintenance system
is the urinary system. It includes the kidneys and of course the
urinary bladder, and all the tubes that connect them and take the urine out from the body. Its main function is, really, to filter blood
and remove waste from it. It also plays an important role in regulating
the content of various elements in the blood. Another maintenance system would be the digestive
system. It includes many organs that make the digestive
tract and organs that assist it. Its function is to receive food, and digest
it (as the name suggests), and to help the nutrient molecules to enter the blood. Okay. Next, we are going to talk about systems that
are involved with control mechanisms. They coordinate and regulate the functions
of many of these other body systems. And, the first one of these that I want to
mention is the nervous system, of course. So, this includes the brain, the spinal cord,
and the nerves which are numerous and extend throughout the body. Their job is to collect information, process
it, and then pass responses to this info. This system is very fast in its response times. But, it is not the only control system. We also have the endocrine system. And, this is all about hormones. Males and females share some of the glands
that secrete hormones, but we also have some that are different. And, the big thing with these chemicals is
that unlike the nervous system that was all about fast nerve impulses, hormones usually
act much longer. And, they act also throughout the entire body. Ok. Let’s talk next about systems that are involved
with the sensory input and motor output. These are aiming to protect and support the
body. And, the first one of these that I want us
to look at is integumentary system. Well, isn’t that a fancy word? Well, this means the skin and nails and the
hair and various glands. And, skin includes a lot of receptors that
collect information from all around the body. And, of course, it forms a barrier between
the inside and outside. Another two that belongs to the sensory input,
and in this case especially, to the motor output, are skeletal and muscular systems. So, the skeletal system is, of course, our
bones. And, muscular system is all about generating
that motor output. It needs, though, the skeletal system to work. Now, the last group that we have includes,
actually, only one system. And, this is of course our reproductive system. And, this is actually the only one of these
systems that you can live without. And, of course, the purpose of this system
is to make babies. The reproductive organs differ between males
and females. Males have testes that produce sperm, and
various glands and ducts that help to carry the semen to (and out) through the penis. And, for females it is, of course, ovaries
that produce eggs. And, various ducts, uterus, vagina and external
genitalia. So, this is where we will finish our survey
of organ systems for now. Next, I have one more section for you, and
that is all about homeostasis.

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