Blood flow in the capillaries is steady despite the rhythmic pumping of the heart because of the

• elasticity of the large arteries

• small diameter of capillaries

• thin walls of the veins

• venous valves

The baroreceptors in the carotid sinus and aortic arch are sensitive to

• a decrease in CO2

• changes in arterial pressure

• a decrease in O2

• all of these

Tags

NGSS.HS-LS1-3

The myocardium receives its blood supply directly from the

• aorta

• coronary arteries

• coronary sinus

• pulmonary arteries

Arterial blood pressure increases in response to

• increasing stroke volume

• increasing heart rate

• atherosclerosis

• rising blood volume

• all of these

The structure of a capillary wall differs from that of a vein or an artery because

• it has two tunics instead of three

• there is less smooth muscle

• it has a single tunic-only the tunica intima

• none of these

Which statement does not accurately describe veins?

• have less elastic tissue and smooth muscle than arteries

• contain more fibrous tissue than arteries

• most veins in the extremities have valves

• always carry deoxygenated blood

Which of the following do not drain directly into the inferior vena cava?

• inferior phrenic veins

• hepatic veins

• inferior mesenteric vein

• renal veins

Which of the following can lead to decreased venous return of blood to the heart?

• an increase in blood volume

• an increase in venous pressure

• damage to the venous valves

• increased muscular activity

Which of the following would not result in the dilation of the terminal arterioles and upstream arterioles in systemic capillary beds?

• a decrease in local tissue O2 content

• an increase in local tissue CO2

• a local increase in histamine

• a local increase in pH

Tags

NGSS.HS-LS1-3

Total peripheral resistance

• is inversely proportional to the length of the vascular bed

• increases in anemia

• decreases in polycythemia

• is inversely related to the diameter of the arterioles