Question 1

The adaptive value of having a complex cascade system for blood clotting is that a defect of one participant in the cascade can be corrected by another down the chain.

Accepted Answer

A complex cascade system for blood clotting ensures precise regulation and amplification of the response, but a defect in one component can disrupt the entire process, as each step is dependent on the previous one.

Question 2

During exercise,sympathetic stimulation of the heart and arteriolar smooth muscle is enhanced because of reflexes triggered by elevated mean arterial pressure and elevated pulse pressure.

Accepted Answer

During exercise, sympathetic stimulation of the heart and arteriolar smooth muscle is enhanced primarily due to reflexes triggered by the central command (brain anticipation of exercise), muscle chemoreceptors, and mechanoreceptors, not directly because of elevated mean arterial pressure or pulse pressure. These reflexes aim to increase cardiac output and redistribute blood flow to meet the metabolic demands of the muscles, rather than responding to changes in arterial pressures.

Question 3

A failing heart does not respond to increased end-diastolic volume by increasing stroke volume.

Accepted Answer

The answer of A failing heart does not respond to...

Question 4

In the clotting cascade,an enzyme activated toward the end of the cascade stimulates its own activation.

Accepted Answer

The enzyme activated toward the end of the clotting cascade is thrombin, which can cleave and activate more prothrombin, leading to further thrombin formation and amplification of the cascade. This process is known as a positive feedback loop.

Question 5

The function of the platelet plug is to block the blood vessel so that blood cannot flow through it.

Accepted Answer

The function of the platelet plug is to seal the damaged area of a blood vessel to prevent further bleeding, but not to completely block the vessel. The platelets form a temporary plug until the more stable fibrin clot forms.

Question 6

Increased concentrations of plasma proteins,increased venous pressure,and lymphatic obstruction all tend to cause tissue edema.

Accepted Answer

The answer of Increased concentrations of plasma proteins,increased venous pressure,and...

Question 7

Hemostatic mechanisms can generally stop blood loss from a small vein that is cut.

Accepted Answer

Hemostatic mechanisms such as vasoconstriction, platelet plug formation, and activation of the coagulation cascade can generally stop blood loss from a small vein that is cut.

Question 8

The Starling forces which influence the rates of movement of fluid out of capillaries and into the interstitial fluids are the same in all sites for capillary exchange - throughout the body.

Accepted Answer

The Starling forces can vary in different tissues and organs based on the characteristics of the capillaries and surrounding tissues, such as vascular permeability and hydrostatic pressure.

Question 9

When arterioles constrict it raises blood pressure and increases the volume of forward flow,while constriction in veins reduces forward flow by decreasing pressure.

Accepted Answer

Constriction of arterioles increases blood pressure and resistance, reducing forward flow, while constriction in veins increases venous return and forward flow by increasing pressure.

Question 10

A blood clot is essentially an intricate network of interlacing strands of thrombin.

Accepted Answer

A blood clot is an intricate network of interlacing strands of fibrin, not thrombin. Thrombin is an enzyme involved in the formation of fibrin from fibrinogen in the blood clotting process.

Question 11

The term AED (Automatic Electronic Defibrillator)refers to a recently developed device used to regulate blood pressure with the surprise benefit of being useful in contraception with some individuals within a narrowly defined age group.

Accepted Answer

The term AED (Automatic Electronic Defibrillator) is a medical device used to restore normal heart rhythm in cases of sudden cardiac arrest. It has no relation to contraception or blood pressure regulation.

Question 12

Chemical mediators released from platelet granules and plasma membranes stimulate contraction of vascular smooth muscle.

Accepted Answer

Chemical mediators such as thromboxane A2 and serotonin released from platelet granules and plasma membranes can stimulate contraction of vascular smooth muscle.

Question 13

Thrombin is inactivated when it binds to heparin.

Accepted Answer

Thrombin is not directly inactivated by heparin; instead, heparin enhances the activity of antithrombin III, which inactivates thrombin and other proteases involved in blood clotting.

Question 14

In the clotting cascade,an enzyme activated toward the end of the cascade inhibits its own activation.

Accepted Answer

The enzyme activated toward the end of the clotting cascade is called thrombin. Thrombin is involved in converting fibrinogen to fibrin, ultimately leading to clot formation. However, thrombin also activates a protein called protein C, which, when activated, inhibits the activity of both thrombin and factors VIIIa and Va, thus effectively downregulating the clotting cascade to prevent excessive and unwanted clot formation. Therefore, the statement is true.

Question 15

Left ventricular failure often results in increased net pulmonary capillary filtration into the interstitial fluid of the lungs and a resulting decrease in the diffusional exchange of O2 and CO2 between lung and blood.

Accepted Answer

Left ventricular failure can lead to increased pulmonary capillary pressure, causing increased net filtration of fluid into the interstitial space in the lungs. This can lead to pulmonary edema, which can impair the exchange of gases between the alveoli and pulmonary capillaries, resulting in decreased diffusional exchange of O2 and CO2 between lung and blood.

Question 16

Hypertension is often treated with drugs that increase total peripheral resistance.

Accepted Answer

Hypertension is often treated with drugs that decrease total peripheral resistance, such as ACE inhibitors, diuretics, beta blockers, calcium channel blockers, and angiotensin receptor blockers. These drugs work by relaxing blood vessels and reducing the amount of force needed to pump blood, ultimately lowering blood pressure.

Quiz 12: Cardiovascular Physiology