Ch 19

Question 1

What are the two primary determinants of long-term arterial pressure level?

Answer 1

1. degree of pressure shift of the renal output curve for water and salt
2. The level of salt and water intake

Question 2

Briefly, what is the effect of increased arterial pressure on the sympathetic nervous system?

Answer 2

SNS activity decreases (as does Angiotensin II and aldosterone

Question 3

What is the basic equation for arterial pressure?

Answer 3

Arterial pressure = cardiac output x total peripheral resistance

Question 4

Where is pro-renin produced and activated?

Answer 4

The juxtaglomerular cells of the kidney in the walls of the afferent arterioles proximal to the glomeruli

Question 5

The juxtaglomerular cells are modified ______ cells

Answer 5

smooth muscle

Question 6

Renin causes catalyzes formation of which substance?

Answer 6

Angiotensin I (from angiotensinogen)

Question 7

what is the action of angiotensin I

Answer 7

-mild vasoconstrictor
-used to form angiotensin II

Question 8

where is angiotensin II produced?

Answer 8

The lungs’ blood vessels, and to a lesser extent, the kidneys and other blood vessels

Question 9

What are the functions of Angiotensin II?

Answer 9

1. Rapid, multifocal vasoconstriction to increase venous return
2. Decreased salt and water excretion by the kidneys (more powerful method)

Question 10

How long does it take the RAAS to become fully active?

Answer 10

About 20 minutes

Question 11

How does angiotensin II cause renal salt and water retention?

Answer 11

1. acts directly on the kidneys
2. causes aldosterone secretion by the adrenal glands, which acts at the kidney to save salt and water

Question 12

How does angiotensin act directly on the kidneys?

Answer 12

1. renal arteriolar constriction to reduce blood flow, reducing pressure in the peritubular capillaries to stimulate fluid reabsorption from tubules
2. acts on tubular cells to increase sodium and water reabsorption

Question 13

which mechanisms show responses to changes in arterial pressure within minutes to seconds?

Answer 13

1. Baroreceptor feedback mechanism
2. The central nervous system ischemic mechanism
3. The chemoreceptor mechanism

Question 14

In a patient with acute severe hemorrhage, what three main results do the nervous mechanisms cause to maintain blood pressure?

Answer 14

1. Venous constriction and transfer of blood to the heart
2. Increased heart rate and cardiac contractility to improve pumping
3. Peripheral arteriolar constriction to impede blood flow out of arteries

Question 15

What three pressure control mechanisms take minutes-hours to fully activate?

Answer 15

1. Renin-angiotensin vasoconstrictor mechanism
2. Stress-relaxation of the vasculature
3. Shift of fluid through tissue capillary walls in and out of circulation

Question 16

Which pressure-regulating mechanism acts over the longest expanse of time?

Answer 16

The renal body fluid mechanism