Lecture 8: Renal/Glomerular Intro

Question 1

Renal corpuscle

Answer 1

• Glomerulus
• Glomerular capillaries
• Afferent/efferent arterioles
• Bowman’s space + capsule

Question 2

Filtration barrier layers in glomerulus

Answer 2

1. Single cell capillary endothelium
2. Basal lamina layer
3. Single cell Bowman’s capsule epithelium

Question 3

Peritubular capillaries

Answer 3

Capillaries that surround cortical layer tubules

Question 4

Types of nephrons

Answer 4

1. Juxtamedullary (15%, deep w/ vasa recta capillaries + H2O resorption gradient)
2. Cortical (shallower)

Question 5

What is a major structure on the distal convoluted tubule that plays a role in BP regulation?

Answer 5

Macula densa and the juxtaglomerular apparatus

Question 6

Ultrafiltrate

Answer 6

Cell-free filtrate containing basically plasma minus larger proteins; produced by glomerular filtration

Question 7

What gets filtered out by the renal corpuscles?

Answer 7

Corpuscles remove large MW and negatively charged molecules from filtrate

Question 8

Net glomerular filtration pressure

Answer 8

P = hydrostatic glomerular cap. P - hydrostatic Bowman’s Space P - oncotic GC P

Question 9

Glomerular Filtration Rate

Answer 9

Volume filtered out per unit time; regulated by neural/hormonal input to aff./efferent arterioles

Question 10

Main features of tubule resorption

Answer 10

1. Large load; 180 L filtered/day
2. Incomplete resorption of waste (mostly excreted)
3. Complete resorption of useful plasma parts (little to no excretion)

Question 11

Proximal tubule roles

Answer 11

• Major solute secretion site
• Most of H2O, non-waste solute resorption

Question 12

Loop of Henle’s roles

Answer 12

Primarily major ion resorption, some H2O; urine concentration/dilution

Question 13

Distal segment roles

Answer 13

Homeostatic finetuning

Question 14

Major functions of kidney

Answer 14

1. Homeostasis (blood/H2O vol., Osm, electrolytes, acid/base)
2. Excretion (waste, drugs/toxins, acid/base)
3. Production (renin, Vit. D, glucose, EPO)

Question 15

Body water volumes

Answer 15

60-40-20 percent of body weights for total H2O, ICF, ECF

Question 16

Renal capillary beds

Answer 16

1. Glomerular
2. Peritubular

Question 17

Glomerulus filtration structures

Answer 17

1. Podocyte pedicel filtration slits
2. Capillary fenestrations
3. Basement membrane

Question 18

Renal Plasma Flow

Answer 18

Flow rate of plasma to kidneys

Question 19

Renal Blood Flow

Answer 19

Flow rate of whole blood to kidneys (plasma + Hcrt)

Question 20

Filtration Fraction

Answer 20

Fraction of plasma that is filtered out by kidneys, = GFR/RPF (20%; ~25% of cardiac output)

Question 21

Equation for GFR

Answer 21

GFR = Kf (P_gc - P_bs - π_gc)
Kf = filtration coefficient; usually GFR = 180 L/day