Glomerular Filtration & Renal Blood Flow

Question 1

The external baroreceptor reflex results in a hormonally-mediated _____.

Answer 1

constriction of the arterioles

Question 2

______ rises rapidly when MAP exceeds its auto-regulatory range.

Answer 2

P_gc

Question 3

What are granular cells?

Answer 3

specialized smooth muscle cells in the afferent arterioles that secrete renin

Question 3

In the equation, GFR = K(P_gc - P_t - π_gc), what is K?

Answer 3

• the product of the specific hydraulic conductivity “ρ” times the total surface area “A” of all the glomeruli in the kidneys
• K= ρA

Question 3

Pgc is very tightly regulated by the process of ______.

Answer 3

glomerular capillary autoregulation

Question 4

Neural stimulation of the afferent arteriole also causes the increased release of _____ from the _____ cells of the JG apparatus.

Answer 4

renin; granular

Question 5

This is a sheet of epi cells with many projections that acts as a molecular sieve.

Answer 5

podocytes

Question 8

The renin/angiotensin axis is stimulated by detection of reduced arteriolar pressure by intrarenal baroreceptors thought to reside on the _____ cells themselves.

Answer 8

granular

Question 9

If a decline in MAP is sensed by the main arteries, what happens?

Answer 9

a baroreceptor reflex = activity of the renal sympathetic nerve increases to cause arteriole constriction

Question 9

What produces renal prostaglandins?

Answer 9

renal interstitial cells

Question 11

What are podocytes?

Answer 11

a sheet of epi cells with many projections that acts as a molecular sieve

Question 11

Name 2 forces that oppose glomerular filtration.

Answer 11

1. backpressure from Bowman’s capsule (P_t)
2. the net osmotic force from serum proteins (COP or π_gc)

Question 13

The flow of the filrate first passes through the ______.

Answer 13

fenestrated glomerular capillary endothelium

Question 14

The renin/angiotensin axis is stimulated by detection of ______ by ______ thought to reside on the granular cells themselves.

Answer 14

reduced arteriolar pressure; intrarenal baroreceptors

Question 15

The coordinate constriction of arterioles during hypovolemia is mediated by which baroreceptors?

Answer 15

the external and renal baroreceptors

Question 16

What is the glomerular basal lamina?

Answer 16

a thick, negatively charged basement membrane secreted by the endothelial and epithelial cells consisting of mucoproteins

Question 16

Where are renal interstitial cells found?

Answer 16

in the medulla between the pyramids

Question 17

Neural stimulation of the _____ also causes the increased release of renin from the granular cells of the JG apparatus.

Answer 17

afferent arteriole

Question 18

What is the normal filtration fraction value?

Answer 18

0.2

Question 19

What is the equation for GFR?

Answer 19

GFR = K(P_gc - P_t - π_gc)

Question 21

What is the size limit for substances trying to freely pass through the glomerulus?

Answer 21

60,000 daltons

Question 22

Why are prostaglandins secreted in the kidney if they counteract the action of the hypovolemic constriction response?

Answer 22

to maintain adequate renal blood flow, specifically at the afferent arteriole, by blunting vasoconstriction

Question 23

The renal solution to hypovolemia: GFR is maintained by ______.

Answer 23

co-ordinate constriction of the afferent and efferent arterioles

Question 24

What is the regulating “valve” to keep the renal blood flow constant, under normal conditions?

Answer 24

the afferent arteriole

Question 25

The ______ is stimulated by detection of reduced arteriolar pressure by intrarenal baroreceptors thought to reside on the granular cells themselves.

Answer 25

renin/angiotensin axis

Question 26

As for any capillary bed, filtration out of the glomerulus is driven by the _______.

Answer 26

blood pressure

Question 27

The podocytes help create and support the ____.

Answer 27

basal lamina

Question 28

When are prostaglandins secreted? What do they do?

Answer 28

they’re secreted in response to angiotensin II and have a local dilatory effect on the renal arterioles

Question 29

The glomerular capillaries are covered by the so-called _____ cells.

Answer 29

mesangial

Question 30

These are specialized smooth muscle cells in the afferent arterioles that secrete renin.

Answer 30

granular cells