Chapter 18/19 (Pt. 2)

Question 1

what symbol do we use for hydrostatic pressure?

Answer 1

P

Question 2

what symbol do we use for osmotic pressure?s

Answer 2

pi

Question 3

pi: hydrostatic or osmotic pressure?

Answer 3

osmotic

Question 4

P: hydrostatic or osmotic pressure?

Answer 4

hydrostatic

Question 5

what factors are pro-filtration?

Answer 5

PGC + piBC

Question 6

what factors are anti-filtration?

Answer 6

PBC + piGC

Question 7

what are the factors that regulate glomerular filtration rate?

Answer 7

glomerular hydrostatic pressure, Bowman’s capsule osmotic pressure, Bowman’s capsule hydrostatic pressure, and glomerular plasma osmotic pressure

Question 8

how do glomerular hydrostatic pressure, Bowman’s capsule osmotic pressure, Bowman’s capsule hydrostatic pressure, and glomerular plasma osmotic pressure function together to regulate glomerular filtration rate?

Answer 8

(PGC + piBC) - (PBC + piGC) = 16 mm Hg

Question 9

how can liver failure lead to kidney failure?

Answer 9

liver makes proteins that remain in the plasma, maintaining the capillary osmotic pressure.

liver failure means no proteins, which decreases glomerular capillary osmotic pressure.

when there’s not enough osmotic counter pressure to counter filtration, glomerular filtration increases, and kidneys are stressed.

Question 10

how does glomerular filtration rate change by constriction of the afferent arterioles?

Answer 10

afferent contract = increased resistance = decreased blood flow to glomerulus = decreased filtration

Question 11

how does glomerular filtration rate change by constriction of the efferent arterioles?

Answer 11

decreasing the exit port size = harder to empty the glomerulus = increased filtration rate

Question 12

there is a plateau in GFR between 80-180 mm Hg. why does filtration rate decrease from 0-80 mm Hg?

Answer 12

not enough BP.

want to minimize fluid volume loss from plasma.

Question 13

there is a plateau in GFR between 80-180 mm Hg. why does filtration rate increase about 180 mm Hg?

Answer 13

too much blood pressure. glomerulus could rupture.

kidney can’t work against that high of blood pressure; increased glom. hydrostatic pressure that drives filtration at a level that the kindey doesn’t like.

Question 14

how is GFR controlled?

Answer 14

by adjusting glomerular capillary bed pressure.

Question 15

hey! why would you want to adjust glomerular capillary bed pressure?

Answer 15

to control GFR

Question 16

what is GFR?

Answer 16

glomerular filtration rate

Question 17

what are two ways to locally control GFR? aka locally adjust glomerular capillary bed pressure

Answer 17

• myogenic (muscle) mechanism
• tubuloglomerular feedback (involves the juxtaglomerular apparatus)

Question 18

what are two ways to control GFR from the outside or extrinsicly?

Answer 18

• hormone action
• neurological activity

Question 19

how does the myogenic response to reduce excessive filtration flow rate work?

Answer 19

increased BP = stretch smooth muscle walls of aff. arteriole = open mechanoreceptor Ca+2 channels = ca-calmodulin vasoconstriction* = limits flow into glomerulus.

*(smooth muscle cells depolarize to activate voltage-gated Ca+2 channels; Ca+2 binds to calmodulin = activates myosin light chain kinase = phosphorylates MLC = ATP hydrolysis = crossbridge formation = smooth muscle contraction)

Question 20

what effect does the contraction of afferent arterioles have on resistance, blood flow rate, and filtration rate?

Answer 20

increases resistance, decreases blood flow rate, decreases filtration rate