Figure 1-4 The heart as a pump.
© Jones & Bartlett Learning.
DescriptionThe heart consists of four main chambers: the two atria and the two ventricles. The atria empty into their corresponding ventricles. The left ventricle empties into the peripheral circulatory system, and the right ventricle empties into the pulmonary system. Veins bring blood to the heart, while arteries take blood away from the heart. As Figure 1-4 shows, this is a closed system. Blood circulates inside this closed system over and over, taking up oxygen in the lungs and giving it up to the peripheral tissues. This is a simplistic explanation of a very complicated system, but it will suffice for our purposes at this time.
Figure 1-4 The heart as a pump.
© Jones & Bartlett Learning.
DescriptionIt is simplest to think of the circulatory system as an engineer would: as a system of interconnected pumps and pipes.
Take a look at Figure 1-5. We see that there are four pumps in sequence. The two small primer pumps are the atria, whose sole purpose is to push a small amount of blood into the two larger ones, the ventricles. The ventricles differ in size and in the amount of pressure that they can generate. Because of the one-way valves found in the venous system, blood can only flow forward.
Figure 1-5 Simplified pump function of the circulatory system.
© Jones & Bartlett Learning.
Description