The _______ prevent back- flow into the atria when the ventricles are contracting.

• semilunar valves

• AV valves

• superior vena cava

• aorta

3. The ______ prevent backflow into the ventricles when the heart is relaxing.

• 3. semilunar valves

• AV valves

• vena cava

• aorta

Artery walls are thick and strong to withstand pressure fluctuations.

• true

• false

Capillary walls are formed of the tunica externa only.

• true

• false

All veins above the diaphragm drain into the inferior vena cava, and those below the diaphragm drain into the superior vena cava.

• true

• false

8. Pulse

• 8. the pressure that blood exerts on the walls of the blood vessels

• an expected consequence of cardiovascular hyperactivity

• 8. the alternate expansion and recoil of a blood vessel wall (the pressure wave) that occurs as the heart beats

3. The time and events occurring from one heartbeat to the next

• heart sounds

• 3. cardiac cycle

• heart murmurs

When we exercise vigorously , there is a generalized vasoconstriction except in the skeletal muscles.

• true

• false

This is caused by sudden postural changes leading to the brief pooling of blood in the lower limbs, reducing blood pressure and, consequently, blood delivery to the brain.

• Chronic hypotension

• orthostatic hypotension

• circulatory shock

the pressure in the arteries at the peak of ventricular contraction

• systolic pressure

• diastolic pressure