Intro to renal function

Question 1

Which hormones are secreted by the kidneys

Answer 1

Renin (JGA granular cells)
Erythropoietin (interstitial cells)
1,25-dihydroxycholecalciferol

Question 2

What things are the kidneys responsible for regulating?

Answer 2

water and inorganic ion balance

body fluid osmolality and volume

Question 3

What does the kidney exrete

Answer 3

metabolic waste (urea, uric acid, creatinine)
foreign chemicals (drugs, pesticides, food additives)

Question 4

Ureter pressure

Answer 4

usually very low

Question 5

Basic unit of kidney

Answer 5

nephron

Question 6

What controls water permeability in the collecting duct?

Answer 6

vasopressin

Question 7

Where is the final concentration of the urine adjusted?

Answer 7

collecting duct

Question 8

Describe location of cortical nephrons

Answer 8

glomeruli in outer cortex

LOH short & don’t extend into inner medulla

Question 9

Describe location of juxtamedullary nephrons

Answer 9

glomeruli near corticomedullary border
LOH long & extend deep into the inner medulla
-ability to produce concentrated urine is proportional to the number of juxtamedullary nephrons

Question 10

3 layers of the filtration barrier of the renal corpuscle

Answer 10

• capillary endothelium
• basement membrane (basal lamina)
• capsular epithelial cells (a. podocytes and b. slits between podocytes which constitute the path of filtrate flow into BC)

Question 11

Juxtaglomerular Apparatus (JGA) function

Answer 11

• helps control GFR

- controls RENIN SECRETION (blood pressure and volume)

Question 12

Where are mesangial cells and what do they do?

Answer 12

found between and within capillary loops of (JGA);

contract in response to angiotensin II

Question 13

What gives off afferent arterioles?

Answer 13

cortical arteries

Question 14

How many afferent arterioles per glomerulus?

Answer 14

One afferent arteriole per glomerulus

Question 15

What supplies blood to the nephron?

Answer 15

peritubular capillaries

Question 16

What are vasa recta and what are 2 imp fxns of them?

Answer 16

specialized peritubular capillaries of JMN
long, hairpin shaped capillaries follow the LOH
supply nutrients to medullary tissue and imp. for recovery of water

Question 17

Renal nerves (type, release, receptors)

Answer 17

SYMPATHETIC (release norepinephrine and dopamine)
ALPHA RECEPTOR present on afferent and efferent arterioles but PRIMARILY AFFERENT
-NO parasympathetic innervation

Question 18

What does stimulation of the SNS tend to do to renal blood flow and glomerular filtration rate?

Answer 18

SNS stim. tends to reduce RBF & GFR
BUT simultaneous release of PGE2 and PGI2 oppose the effect
reductions in RBF and GFR are minimized

Question 19

How are granular cells innervated and what happens when they are innervated?

Answer 19

Granular cells (JGA) innervated by SNS;
RENIN released upon stimulation of beta receptors

Question 20

What does glomerular filtration do? What is GFR?

Answer 20

produces a protein-free filtrate

GFR is 120-125 ml/min

Question 21

What is it called when a substance is moving from tubular lumen to peritubular capillaries?

Answer 21

Tubular REABSORPTION

Question 22

What is it called when a substance moves from the peritubular capillaries to the tubular lumen?

Answer 22

Tubular SECRETION