Renal 2 Don

Question 1

MALTS

Answer 1

Mannitol PCT
Acetazolamide PCT
Loop diuretics LOH
Thiazide diuretics DCT
Spironolactone CD

Question 2

Normally, selective permeability permits approximately ___ of plasma elements to pass into the bowmans capsule, cells and proteins more than 60kDa ___

Answer 2

25%
Can not pass

Question 3

The basement membrane is ____ charged due to ___ which composes it. ___ charged proteins are thus repelled and are unable to pass thru it.

Answer 3

Negatively
glycoproteins
Negatively

Question 4

The two major determinants of filtration pressure are ___ and ___

Answer 4

glomerular capillary pressure (Pgc)
glomerular oncotic pressure (Pgc)

Question 5

Normal GFR is ___, AKA ___ per day

Answer 5

120ml/ min
180L/ day

Question 6

The vasa recta descends _____

Answer 6

Deep into the medulla, parallel to the LOH.

Question 7

RBF is about ___ of CO

Answer 7

20%
2nd to only the liver

Question 8

The vast majority of what is filtered is ___

Answer 8

reabsorbed

Question 9

High hydrostatic pressure in the glomerular capillaries (60mmHg) causes ___

Answer 9

Rapid fluid filtration

Question 10

Lower hydrostatic pressure in the peritubular capillaries (13mmHg) causes ___

Answer 10

rapid reabsorption

Question 11

What are the factors that determine GFR?

Answer 11

1- ultrafiltration coefficient (cap permeability)
2- glomerular oncotic pressure (no protein, so direction should oppose filtration)
3- glomerular capillary pressure ( controlled by afferent and efferent arterioles)
4 capillary plasma flow rate

Question 12

Formula for net filtration pressure-

Answer 12

Normal- 10mmHg
glomerular hydrostatic pressure- bowmans capsule pressure - glomerular oncotic pressure

Question 13

What determines the glomerular hydrostatic pressure?

Answer 13

Arterial pressure- Increase MAP increases GFR, autoregulation
Afferent arteriolar resistance- Constriction reduces GFR, dilation increases GFR
Efferernt arteriolar resistance- constriction is biphasic- mild constriction increases GFR, excessive constriction reduces RBF and GFR, dilation reduces GFR

Question 14

Most important factor of GFR

Answer 14

Glomerular hydrostatic pressure
(per apex, not even in dons top 4)

Question 15

GFR is autoregulated between what pressures?

Answer 15

SBP 80-200

Question 16

GFR is autoregulated by what 2 mechanisms?

Answer 16

Constriction/ dilation of afferent and efferent arterioles
Increased Na delivery to the macula densa will decrease GFR via adenosine induced vasoconstriction of the afferent arteriole

Question 17

What is the macula densa

Answer 17

Specialized group of epithelial cells in the distal tubules
contains the golgi apparatus which secretes substances towards the arterioles

Question 18

Decreased Na affects the macula densa by ___ and ___

Answer 18

1- drops resistance and increases GFR
2- Increases renin release from JG cells of the afferent and efferent arterioles, end product is increased GFR

Question 19

If a substance is completely reabsorbed, then the clearance is ___

Answer 19

0

Question 20

What are the 3 mechanisms of reabsorption and secretion?

Question 20

Renal function compared to % of functioning nephrons and GFR

Answer 20

normal renal- 100% function, 120ml/min
Reduced renal- 10-40% function, 10-80 ml/min
Renal failure- <10% function, <12ml/min