Renal Hormones and Autocoids

Question 1

What are the 2 intrinisc renal mechanisms for autoregulation of GFR and renal blood flow?

Answer 1

myogenic mechanism tubuloglomerular feedback mechanisms

Question 2

Myogenic mechanism

Answer 2

changing pressure of afferent arteriole

Question 3

What does vasoconstriction of afferent arteriole cause

Answer 3

decreases RBF and GRF

Question 4

How is GFR regulated

Answer 4

autoregulated

Question 5

How is RBF related to GFR

Answer 5

autoregulated in parallel with GRF - dependent on GRF

Question 6

tubluoglomerular feedback

Answer 6

mechanism for autoregulation when there is increased renal arterial pressure

Question 7

What happens to fluid volume when there is incrased renal arterial pressure

Answer 7

less time to absorb water, larger than normal amt reaches loop of Henle per unit time

Question 8

Function of Macula densa

Answer 8

sensor - senses flow via cilia as well as NaCl. chemical signals it releases inhibits release of renin

Question 9

How can tubuloglomerula feedback help prevent excessive fluid losses after damage to kidney proximal tubules?

Answer 9

If proximal tubular reabsoprtion is reduced there is excessive water and NaCl going to distal tubule, then you will get vasoconstriction of afferent arteriole

Question 10

Why do we have autoregulation?

Answer 10

because we want to be able to deal with the many changes in BP, we don’t want to have to involve the renal system every time that happens

Question 11

how does autoregulation help patients with hypertension?

Answer 11

Helps compensate for the fact that nephrons are getting killed off

Question 12

what are the vasodilator hormones?

Answer 12

Prostacyclins - PGE2 and PGI2

Question 13

What are the vasoconstrictor hormones?

Answer 13

angiotension II, norepinephrine, vasopressin, endothelin

Question 14

What drug inhibits prostaglandin synthesis

Answer 14

N-SAIDS

Question 15

What releases renin

Answer 15

kidney

Question 16

What releases angiotensin

Answer 16

liver

Question 17

what releases aldosterone

Answer 17

adrenal cortex

Question 18

What stimulates release of renin

Answer 18

low blood pressure

Question 19

what cells release renin

Answer 19

juxtaglomerular cells

Question 20

What division of the autonomic nervous system innervates the cells that produce renin

Answer 20

sympathetic stimulation of Beta1 adrenergic receptors

Question 21

what happens to renin if you increases nervous stiulation

Answer 21

increases renin release

Question 22

how does angiotensin II affect vascular smooth muscle

Answer 22

vasoconstriction

Question 23

how does angiotensin II affect efferent arteriole

Answer 23

constriction

Question 24

How does angiotensin II affect proximal tubule sodium reabsorption

Answer 24

increases

Question 25

how does angiotensin II affect thirst

Answer 25

increases

Question 26

how does angiotensin II affect release of ADH

Answer 26

increases

Question 27

How does angiotensin II affect sympathetic tone

Answer 27

increases

Question 28

What is the major source of erythropoietin

Answer 28

kidney (liver is minor source)

Question 29

What is the major stimulation of erythropoietin

Answer 29

low oxygen

Question 30

why is the kidney important in production of Bit D

Answer 30

it is converted to the active form in the kidney and is stimulated by PTH

Question 31

what does active vit D do

Answer 31

increases absorption of calcium and phosphate in the intestine

Question 32

function of PTH

Answer 32

stimulates final activation of vit D in kidney
increases renal-tubular calcium reabsoption
reduces proximal tubular reaborption of phosphate (increases phosphate excretion)

Question 33

What is the source of FGF23

Answer 33

osteoblasts and osteocytes in bone

Question 34

actions of FGF23 in kidney

Answer 34

decreases reabsorption of phosphate

decreases productino of calcitriol

Question 35

what stimulates the secretion of FGF23

Answer 35

elevated levels of phosphate

calcitriol

Question 36

How does chronic renal failure affect your pt’s bone

Answer 36

low GFR causes high phosphate in plasma
causes elevated PTH
causes increased bone resorption