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Circulatory system


Blood cells flowing through an arteriole (small artery)


How blood flows from arteries, to capillaries, and then to veins


Heart-lung system



The Zen of Cardiac Blood Flow

heart blood flow chambers

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Sample questions

The heart is part of the circulatory system.The heart is part of the circulatory system.

a. Describe the primary function of the heart.

Medical researchers are working on developing artificial hearts. Three of the many requirements for the design of an artificial heart are listed below.

• An artificial heart must connect to the pulmonary artery (artery connected to the lungs).

• An artificial heart must connect to the superior vena cava and inferior vena cava(large veins).

• An artificial heart must be able to function at different speeds when a person is exercising and is at rest.

b. Describe how each of the requirements listed above would help the body of an individual with an artificial heart function normally.


In the human heart, a group of cells in the wall of the right atrium produces nerve impulses that stimulate cardiac muscle. What do these nerve impulses directly control?

A. the amount of oxygen in the blood
B. the release of platelets into the blood
C. the speed at which the heart pumps blood
D. the path blood takes when it leaves the heart


Low blood pressure can be life-threatening. To help maintain a stable blood pressure, receptors in the heart detect changes in blood pressure. Information about blood pressure changes is then sent to the brain. If blood pressure is too low, the brain sends a message to the heart to beat faster. Based on this information, which of the following systems are directly involved in keeping blood pressure stable?

A. circulatory, muscular, nervous
B. circulatory, immune, skeletal
C. excretory, immune, muscular
D. excretory, nervous, skeletal



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