Question 1

Mean arterial pressure

Accepted Answer

Mean arterial pressure (MAP) is indeed proportional to cardiac output (CO) times peripheral resistance (PR), following the formula MAP ≈ CO × PR. This relationship highlights the importance of both the volume of blood the heart pumps and the resistance it must overcome in the systemic circulation.

Question 2

Cardiac output is equal to stroke volume times heart rate.

Accepted Answer

Cardiac output is the volume of blood the heart pumps per minute, and it is calculated by multiplying the stroke volume (the amount of blood pumped by the heart in one contraction) by the heart rate (the number of heartbeats per minute).

Question 3

A patient was administered drugs to reduce her heart rate. Which of the following conditions was she likely to have experienced, and what other factor could be altered to enhance the current treatment?

Accepted Answer

Reducing heart rate is a common strategy in treating hypertension to decrease the workload on the heart and lower blood pressure. Vasodilation would further help in this treatment by reducing peripheral resistance, thereby lowering blood pressure even more.

Question 4

Considering the distribution of sympathetic and parasympathetic fibers in the peripheral nervous system, damage to which of the following nerves would have the greatest impact on blood vessel walls?

Accepted Answer

Sympathetic fibers, which significantly influence blood vessel walls by causing vasoconstriction or vasodilation, predominantly originate from the thoracic nerves. The sympathetic nervous system plays a crucial role in regulating blood flow and blood pressure, and thoracic nerves are a major component of this system.

Question 5

The distribution of blood volume in veins are arteries is very close to equal.

Accepted Answer

Veins contain a larger portion of the blood volume, approximately 70%, due to their capacity to expand, acting as blood reservoirs, whereas arteries contain a smaller percentage, around 30%, as they are more rigid and primarily function to distribute blood from the heart to the rest of the body.

Question 6

The vasomotor center

Accepted Answer

The vasomotor center primarily sends low frequency action potentials to blood vessels to maintain their tone, which is crucial for regulating blood pressure and flow.

Quiz 21: Cardiovascular System: Blood Vessels and Circulation