Video Transcript
Fill in the blanks. The blood vessels that carry blood
away from the heart are the blank; the blood vessels that carry blood toward and
into the heart are the blank. (A) Arteries, veins or (B) veins,
arteries.
Here is a simplified diagram of the
human heart. Whenever we look at a diagram such
as this, we need to remember that the left side of the image represents the right
side of the heart and the right side of the image represents the left side of the
heart. This is because we always draw it
as if we are looking at the heart of person standing facing us. You may recall that the right side
of the heart receives deoxygenated blood and pumps it out to the lungs so that it
can pick up oxygen. By contrast, the left side of the
heart receives oxygenated blood returning from the lungs and pumps it all around the
rest of the body so the oxygen can be delivered to the tissues for cellular
respiration.
Now, let’s have a look at the two
types of blood vessel that are responsible for carrying blood toward and away from
the heart. The first is a vein. Veins have a thin wall and a large
lumen, which is just the scientific name for the cylindrical space in the middle of
vessels that the blood flows through. Veins also have valves which open
and close to prevent blood from flowing backwards. These features make veins well
adapted for carrying blood that is returning to the heart from the tissues and is
therefore under low pressure.
The second type of blood vessel is
an artery. Arteries have a thick, elastic wall
and a narrow lumen. These adaptations mean that
arteries are able to withstand and maintain the high pressure that blood is under as
it flows away from the heart. Blood leaving the heart must be
under high pressure to ensure it reaches the lungs and all the other tissues of the
body which need oxygen for cellular respiration. We can now label the two blood
vessels at the top of the heart diagram as arteries and the remaining ones as
veins.
A good way to remember that
arteries carry blood away from the heart is that the words “artery” and “away” both
start with the letter “a.” We can also remember that veins
carry blood into the heart because within the word “vein” is the word “in.” We have therefore determined that
the correct answer to the question is (A). The blood vessels that carry blood
away from the heart are the arteries; the blood vessels that carry blood toward and
into the heart are the veins.
