To the Heart of the Matter: The Cardiovascular System in ASL and English with Paul Buttenhoff and Kendall Kail Interpretations by Patty McCutcheon Produced by Todd Tourville

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The Cardiovascular System - Warm-up Lecture

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Paul Buttenhoff in English

Closed captioning can be controlled by the CC button in lower right corner.

English Transcript

Today I’d like to talk to you a little bit about the cardiovascular system, one of several systems in your body that function in transportation.
However, the cardiovascular system is the most important system in terms of carrying things around in your body. We have to talk just a little bit about the components of the cardiovascular system before we can see how it works as a unit. To strip things down, your cardiovascular system contains two primary regions. The first region will be your heart, which is an organ about the size of a softball, more or less; it is located in the upper portion of your body called your thorasic cavity. We also, from the heart and to the heart have a series, miles and miles actually, of tubes that carry blood both away from the heart and eventually back towards the heart.

Your heart has several special properties. First of all think of its job. It never gets a break, never gets a fifteen-minute time out, it beats
from development embryologically until death. The heart is the only location in the body where we find cardiac muscle cells. These cells
are extremely durable. These cells have incredible endurance and these cells also have a few other special properties. The cells in your
heart can act all by themselves. If you leave your heart alone it will beat, on average, about 100 times per minute. It can work without
any intervention from your brain or spinal cord. However we usually try to control it a little more readily because sometimes we sleep
and we shut, or slow our heart down a little bit. Or, sometimes we’re in a nasty traffic situation and blood pressure goes up a little bit
and things start working a little more rapidly.

A heart is going to have several primary functions, using this striated or stripped arranged in a very specific fashion, cardiac muscle, your
heart will receive blood from body tissues. Your heart will then send blood up to your lungs where it can fill with the very important molecule called oxygen. Blood will return to the heart, now containing oxygen, and last but not least, your heart has the responsibility of
sending this blood, that now contains oxygen the stuff that life is made of for us out to every single tissue in the body.

If you were to look inside the heart you would see four small hollow spaces. These hollow spaces are called chambers and they have
several different functions. On the right side of the heart there are two chambers, a top and a bottom chamber as there are on the left
side of the heart. The right side of the heart specializes in dealing with blood that does not contain oxygen. The left side of the heart
specializes in receiving and pumping to the rest of the body good, oxygenated, red, perfect, beautiful blood. In order to operate effectively,
we’ve got to control these chambers. These four separate spaces controlled and surrounded by cardiac muscle have to be coordinated.
If they did their own thing, we wouldn’t be around very long to worry about them.

There’s a small region called a pacemaker located on the right side of your heart. Your pacemaker is going to be important because,
although the heart can operate by itself, it’s truly the pacemaker, as the name implies that sets the pace and causes each contraction.
Under resting conditions an average heartbeat might beat 80 times per minute, although it can go up to as many as 200 per minute during
heavy activity or stress and it can also drop significantly lower. The pacemaker is a special group of cells that generates a tiny little
electrical impulse, every so often. We’ll say 100 times per minute. After that impulse is generated, your heart becomes excited. First
of all, the top half of the heart becomes excited and then a split second later the bottom half of the heart becomes excited. By having
these hollow chambers that can receive and squeeze blood in different directions and by regulating them in a specific fashion, we can
very effectively take blood into our heart, send it up to our lungs, return oxygenated blood to the heart and last but not least send that
good oxygenated blood out to the body.

In order to carry oxygen to tissues, maybe your big toe, maybe your eyeball or your pancreas, we are going to use hollow tubes that are
surrounded by muscle that we collectively refer to as blood vessels. Now blood vessels come in a bunch of different varieties perhaps
you’ve heard the term arteries or arterioles or capillaries or perhaps venules or veins. There are going to be several different types of
hollow tubes that carry blood away from your heart, down to some region in your body and there will be several types tubes that carry
blood from that region in your body back to your heart. It’s really an incredible loop. Every day your cardiovascular system, your heart
and your blood vessels function by moving about 2000 gallons of blood. Now you don’t have 2000 gallons of blood in you, what that
2000 represents is your internal blood volume recycled many times. It’s a wonderful recycling system in our body.

Blood flows away from the heart in structuries… excuse me, in structures called arteries. Once blood gets to your big toe or your pancreas,
oxygen and glucose and sugar and all the nutrients that your big toe needs to survive, on a minute to minute basis, are delivered
from arteries. Your big toe, as a result of being alive, produces waste materials that must be removed, less they cause harm. Materials
such as carbon dioxide, a waste product, and some other acids that can cause harm are carried from your big toe, for example, back
up to the heart through structures known as venules or veins. So, we really have two systems; we have an away system from the heart
and we have a towards system from the heart. Using both of these loops and a centralized pump, we can effectively take blood that’s
deoxygenated and fill it with oxygen using small chemicals. We can send that good blood out to the body and we can return wastes to
the heart where they can be gotten rid of by your respiratory system.

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