Arteries | Veins | Lymphatics
| These vessels carry blood from the heart to
the rest of the body. This blood contains oxygen from the lungs. The heart
pumps the blood around the arteries. This is responsible for the pulses we
can feel.
The major arteries branch into smaller arteries, then into arterioles and finally into capillaries. These are tiny blood vessels in all the body tissues. It is here that the red cells in the blood give up their oxygen to the tissues and pick up carbon dioxide from them. Top | press 'back' on your browser |
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| From the capillaries in the tissues, blood
enters very small veins called venules. From here into smaller veins
before entering the major veins. These major veins carry blood from the the body
to the heart. There is no 'pump' for this. When we use our muscles they
squeeze blood towards the heart and then valves in the veins prevent it flowing
back the wrong way.
This blood has little oxygen in it as it has been removed by the body. The body removes carbon dioxide into this blood. The heart then pumps the blood to the lungs where carbon dioxide is removed and we breathe it out. Oxygen is added to the blood and returned to the heart ready for distribution to the body. Top | press 'back' on your browser |
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As the blood enters the body tissues through the arteries some of the fluid in it is lost to the tissues (through the capillaries) and the rest of the blood returns to the heart in the veins. This fluid is eventually returned to the blood stream through very small vessels called lymphatics. Problems with these can cause swelling such as in the leg or arm.
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