Ch. 19

________ is the regulation of blood flow by local mechanisms within a capillary bed.

Autoregulation

In comparing a trained athlete to a non-athlete, which of these comparisons is false?

Both hearts weigh about the same.

Where are the sensors for the arterial baroreceptor reflex located?

carotid sinus and aortic arch. The sensors are the arterial baroreceptors themselves, located at the carotid sinus and aortic arch. They detect changes in blood pressure by the degree of stretch on the blood vessel.

The net hydrostatic pressure (HP) is the hydrostatic pressure in the __________ minus hydrostatic pressure in the __________.

capillary; interstitial fluid

Chemoreceptor reflexes respond to

carbon dioxide. pH oxygen

Which of the following would cause vasodilation of arterioles?

decreased activity of the sympathetic nervous system. A decrease in the activity of the sympathetic nervous system would result in decreased activity of vasomotor fibers.

Which of the following would have the greater effect on vascular resistance?

decreasing the diameter of a blood vessel by 1/2

Averaged over a few heartbeats, venous return is ________ cardiac output.

equal to

If blood pressure is increased at the arterial baroreceptors, what would happen with the activity level of the parasympathetic nervous system (PNS) and sympathetic nervous system (SNS)?

increased PNS activity and decreased SNS activity

Each of the following will cause an increase in blood pressure except

increased levels of ANP (atrial natriuretic peptide).

Which net pressure draws fluid into the capillary?

net osmotic pressure

The colloid osmotic pressure in the capillary is caused by __________.

proteins in the blood. non-diffusible proteins in the plasma exert the colloid osmotic pressure, which pulls fluid into the capillary.

The difference between the systolic and diastolic pressures is called the ________ pressure.

pulse

increased activity of vagus nerve (parasympathetic) and decreased activity of sympathetic cardiac nerves

reduction of heart rate and contractility, lower cardiac output, lower blood pressure

Angiotensin II effects include which of the following?

stimulation of thirst

Reabsorption of fluid into the capillary takes place at the arterial end or venous end of the capillary?

venous. because the hydrostatic pressure of blood (which favors filtration out of the capillary) is lowest in the venous end of the capillary.

If a person has a blood pressure of 120/90, his mean arterial pressure would be ________ mm Hg.

100 90+(120-90)/3 = 100

Which of the following would reflect the typical net hydrostatic pressure (HP) at the arterial end of the capillary?

34 mm Hg. HPc (35 mm Hg) - HPI (1 mm Hg) = 34 mm Hg, which is the net hydrostatic pressure at the arterial end. The hydrostatic pressure of the blood is much higher at the arterial end of the capillary, thus favoring filtration.

Paul has a horrible chainsaw accident and cuts several major blood vessels in his head and neck. As a result of this injury, you would expect to observe all of the following except

A. an increase in cardiac output. (not) B. cold, clammy skin. C. an increased heart rate. D. an increased secretion of renin by the kidneys. E. an increased total peripheral resistance.

Which of the following factors will increase the net filtration pressure to move fluid out of capillaries?

A. decreased plasma albumen B. decreased tissue hydrostatic pressure C. increased blood hydrostatic pressure

To defend blood volume against dehydration, the body

A. experiences an increase in the blood colloidal osmotic pressure. B. increases water intake. C. accelerates reabsorption of water at the kidneys. D. experiences a recall of interstitial fluids.

During exercise,

A. venous return increases. B. both cardiac output and stroke volume increase. C. vasodilation occurs at the active skeletal muscles.

Which statement regarding irreversible shock is true?

Circulatory collapse occurs when arteriolar smooth muscles and precapillary sphincters become unable to contract

________ refers to all the factors that resist blood flow in the entire circulatory system.

Total peripheral resistance

ADH and aldosterone secretion are part of the body's long-term compensation for

a serious hemorrhage

A decrease in blood pressure at the arterial baroreceptors would result in which of the following?

an increase in heart contractility. Sympathetic nervous system activity would be increased because of the low blood pressure. Sympathetic fibers go to the ventricles of the heart and increase their contractility. An increase in contractility would increase stroke volume which would lead to an increase in cardiac output and blood pressure.

Stimulation of the adrenal medulla would result in which of the following?

an increase in heart rate and contractility

Sensory neurons that are part of the chemoreceptor reflexes are found in the

arch of the aorta. medulla oblongata. common carotid artery

The main control of peripheral resistance by the vasomotor centers occurs in the

arteriole

In the capillaries, hydrostatic pressure (HP) is exerted by __________.

blood pressure. blood pressure is the driving force for filtration.