Lecture 62 - RAAS & Regulation

Question 1

how is whole body water regulated

Answer 1

with NaCl

Question 2

what controls NaCl and water excretion

Answer 2

1. Renin-Angiotensin-Aldosterone
2. Antidiuretic Hormone (ADH)
3. Sympathetic Nervous System
4. Atrial & Brain natriuretic peptide (ANP/BNP)

Question 3

granular cells in the juxtaglomerular apparatus respond to

Answer 3

changes in pressure

Question 4

decreased pressure causes the release of

Answer 4

renin

Question 5

describe the function of renin

Answer 5

• acts as enzyme
• converts angiotensinogen to angiotensin I

Question 6

what are 3 causes renin release

Answer 6

1. perfusion pressure (decreased)
2. activated sympathetic nervous system
3. low NaCl in distal tubule

Question 7

what cleaves angiotensin I

Answer 7

angiotensin-converting enzyme

Question 8

what are the physiological effects of angiotensin II

Answer 8

1. arterial vasoconstriction (increase BP)
2. constrict efferent arteriole (increase GFR)
3. stimulates ADH and thirst (increase volume)
4. stimulates aldosterone secretion (increase ECF volume)
5. enhance NaCl absorption (increase ECF volume)

Question 9

ACE inhibitors

Answer 9

• inhibit the production of angiotensin II
• interrupt RAAS cascade
• tx for heart failure and hypertension

Question 10

aldosterone functions

Answer 10

• modulate Na+ and K+ balance
• stimulate Na+ reabsorption in collecting duct (increase blood Na+)
• stimulate K+ secretion in collecting duct

Question 11

hypoadrenocorticism

Answer 11

decreased Na+ and increased K+ in PLASMA

Question 12

what is the role of ACE in the RAAS cascade

Answer 12

cleaving angiotensin I to II

Question 13

increased ADH/AVP

Answer 13

expands ECF volume

Question 14

decreased ADH/AVP

Answer 14

decreased ECF volume
diuresis

Question 15

describe renal alpha-adrenergic activation

Answer 15

arteriole vasoconstriction (afferent > efferent)

decreases hydrostatic pressure to glomerulus and GFR

Question 16

describe renal beta-adrenergic activation

Answer 16

causes renin secretion and increases NaCl reabsorption

Question 17

what is the balance to RAAS

Answer 17

ANP/BNP

Question 18

where is ANP and BNP produced/stored

Answer 18

cardiac myocytes

Question 19

physiologic responses of ANP/BNP

Answer 19

1. vasodilation of afferent
2. vasoconstriction of efferent
3. inhibition of renin
4. inhibition of aldosterone
5. inhibition of ADH

Question 20

describe the ANP/BNP cascade from start to effect

Answer 20

1. increased intravascular volume
2. increased stretch in atria/ventricle
3. increased ANP/BNP
4. increased GFR
5. decreased RAAS activation to lower BP, increase diuresis, and lower ECFV