Explain the structure of arteries, veins, and capillaries, and how blood flows through the body

Blood primarily moves through the body by the rhythmic movement of smooth muscle in the vessel wall and by the action of the skeletal muscle as the body moves. Blood is prevented from flowing backward in the veins by one-way valves. Blood flow through the capillary beds is controlled by precapillary sphincters to increase and decrease flow depending on the body’s needs and is directed by nerve and hormone signals. Lymph vessels take fluid that has leaked out of the blood to the lymph nodes where it is cleaned before returning to the heart. During systole, blood enters the arteries, and the artery walls stretch to accommodate the extra blood. During diastole, the artery walls return to normal. The blood pressure of the systole phase and the diastole phase gives the two pressure readings for blood pressure.

What You’ll Learn to Do

• Explain the structure of arteries, veins, and capillaries
• Describe the system of blood flow through the body
• Identify the importance of blood pressure
• Describe how blood pressure is regulated

Learning Activities

The learning activities for this section include the following:

• Blood Vessels
• Blood Circulation
• Blood Pressure
• Self Check: Blood Flow and Blood Pressure Regulation