RBF & GFR Lecture

Question 1

What determines Glomerular Capillary hydrostatic Pressure (Pgc)?

Answer 1

Renal arterial blood flow
Afferent arterole resistance
Efferent arteriole resistance

Question 2

What influences the Ultrafiltration coefficient (Kf)?

Answer 2

Permeability and surface area of the glomerulus

Question 3

What cells can change the surface area of the glomerulus and how does this effect the Ultrafiltration coefficient?

Answer 3

Messangial cells contract and can reduce surface area

This reduces the value of Kf

Question 4

How does the Ultrafiltration pressure change over the length of the glomerular capillary?

Answer 4

Fluid volume in the capillary decreases as it travels along the glomerular capillary, leaving behind proteins (which causes an increase in oncotic capillary pressure)

The other pressures remain constant

Puf = Pgc - Pbs - “pi”gc

So if “pi”gc increases, then Puf decreases

Question 5

What happens to Puf, RBF, GFR, and Peritubular Hydrostatic pressure when the afferent arteriole is constricted?

Answer 5

Puf decreases
RBF decreases
GFR decreases
Peritubular Hydrostatic Pressure decreases

Question 6

What happens to Puf, RBF, GFR, and Peritubular Hydrostatic pressure when the afferent arteriole is dilated?

Answer 6

Puf increases
RBF increases
GFR increases
Peritubular Hydrostatic Pressure increases

Question 7

What happens to Puf, RBF, GFR, and Peritubular Hydrostatic pressure when the efferent arteriole is constricted?

Answer 7

Puf increases
RBF decreases
GFR increases or remains the same
Peritubular hydrostatic pressure decreases

Question 8

What happens to Puf, RBF, GFR, and Peritubular Hydrostatic pressure when the efferent arteriole is dilated?

Answer 8

Puf decreases
RBF increases
GFR decreases
Peritubular hydrostatic pressure increases

Question 9

What chemical signals cause afferent arteriole to dilate?

Answer 9

Prostaglandins
NO
Bradykinin
Dopamine
ANP

Question 10

What chemical signal(s) cause afferent arteriole constriction?

Answer 10

ACE-inhibitors

Sympathetics

Question 11

What chemical signal(s) cause efferent arteriole dialtion?

Answer 11

Vasoactive dilators

Question 12

What chemical signal(s) cause efferent arteriole constriction?

Answer 12

Angiotensin II

Question 13

Describe the local myogenic feedback mechanism in the kidney

Answer 13

Blood vessels resist stretch during periods of high blood pressure

Smooth muscle in vessels contract in response to calcium signaling

Afferents contract, efferents dilate