Summarizing Blood Flow and Blood Pressure Regulation

Summary

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.

Glossary

blood pressure (BP)

pressure of blood in the arteries that helps to push blood through the body

cardiac output

the volume of blood pumped by the heart in one minute as a product of heart rate multiplied by stroke volume

lymph node

specialized organ that contains a large number of macrophages that clean the lymph before the fluid is returned to the heart

peripheral resistance

resistance of the artery and blood vessel walls to the pressure placed on them by the force of the heart pumping

precapillary sphincter

small muscle that controls blood circulation in the capillary beds

stroke volume>

- the volume of blood pumped into the aorta per contraction of the left ventricle