Blood Vessels
Blood VesselsBlood vessels are anything that carries blood. Think about how an old ship was called a vessel, that is because a vessel carries something. There are three major types of blood vessels: Arteries, veins, and capillaries.
Arteries: Usually shown as red in most diagrams of the circulatory system. These blood vessels carry blood AWAY from the heart. These structures are very thick walled, muscular structures because of the high pressure of the blood after leaving the heart. Think of arteries as a highway(Like 59 or I-10). But like how a highway is huge and can hold a bunch of cars, you can get off the high way and find yourself on a much smaller road with much less traffic, these smaller roads are capillaries. |
Capillaries:
These blood vessels are the smallest type. Like a small road off the highway cells have to line up one at a time in a single file line to move through the capillary. This allows oxygen and nutrients to enter the body cells from the red blood cells, and allows carbon dioxide and wastes to diffuse into the red blood cells. After the blood moves through the capillaries, it heads back towards the heart.
Veins:
Usually shown as blue in most diagrams of the circulatory system.
These blood vessel carry blood to the heart. These are large structures with little muscle around the outside because of the fading pressure of the blood stream when it leaves the heart.
These blood vessels are the smallest type. Like a small road off the highway cells have to line up one at a time in a single file line to move through the capillary. This allows oxygen and nutrients to enter the body cells from the red blood cells, and allows carbon dioxide and wastes to diffuse into the red blood cells. After the blood moves through the capillaries, it heads back towards the heart.
Veins:
Usually shown as blue in most diagrams of the circulatory system.
These blood vessel carry blood to the heart. These are large structures with little muscle around the outside because of the fading pressure of the blood stream when it leaves the heart.
- At what point on the picture above do you think the red blood cells trade their O2 and nutrients to the body cells for CO2 and wastes?