intro to renal function, Lect 1

Question 1

function of kidney

Answer 1

1. regulates water and inorganic ions
2. regulates osmolality and volume (via BP)
3. excretes metabolic waste
4. secretes hormones
5. regulate bicarbonate levels

Question 2

where is renin secreted

Answer 2

juxtaglomerular cells

Question 3

what secretes erythropoietin

Answer 3

renal interstitial cells

Question 4

how does kidney create a patient who is in a water steady state? negative water balance? positive water balance?

Answer 4

1. steady state: water input - (water output (fecal, sweat, insensible) + urine) = 0
2. negative water balance: water input - (water output (fecal, sweat, insensible) + more urine) = -X
3. positive water balance: water input - (water output (fecal, sweat, insensible) + less urine) = + X

Question 5

what are some conditions that can result in a negative sodium and water balance?

Answer 5

• less sodium and water in body than normal
  
  • diarrhea
  • diurectic medication
  • insufficient aldosterone (adrenal dysfunction)

Question 6

what are some conditions that can result in a positive sodium and water balance?

Answer 6

• excess steroids
• congestive heart failure
• salt-retaining disease (hyperaldosteronism)

Question 7

renal calyces drain into?

Answer 7

renal pelvis

Question 8

outer, granular portion of kidney? inner, striated portion of kidney?

Answer 8

1. cortex
2. medulla

Question 9

what is the basic unit of the kidney

Answer 9

nephron

• there are millions in each kidney

Question 10

renal corpuscle

Answer 10

• comprised of glomerulus and bowman’s capsule

Question 11

basic function of proximal tubule

Answer 11

• drains Bowman’s capsule

Question 12

60-80% of filtered solute and water is reabsorbed from what part of the nephron? (hint: isosmotic)

Answer 12

proximal tubule

• does not concentrate urine

Question 13

basic function of loop of henle

Answer 13

• generate osmotic gradients in medulla that allow kidney to concentrate the urine

Question 14

juxtaglomerular apparatus

Answer 14

where distal tubule passes between afferent and efferent arteriole

Question 15

area in nephron where some reabsorption of water and ions occurs, fluid is isosmotic or hyposmotic

Answer 15

distal convoluted tubule

Question 16

water permeability in the collecting duct is controlled by?

Answer 16

vasopressin

Question 17

site where the final concentration of urine is adjusted (urine may be iso-, hypo-, or hyperosmotic)

Answer 17

collecting duct

Question 18

differentiate between cortical nephrons and juxtamedually nephrons

Answer 18

• cortical nephrons
  
  • glomeruli in outer cortex
  • LOH short and does not extend into inner medulla
• juxtamedually nephrons
  
  • glomeruli naer corticomedullary border
  • LOH long and extends into inner medulla

Question 19

ability to produce concentrated ruine is thought to be proportional to the number of

Answer 19

juxtamedullary nephrons

Question 20

collecting ducts are shared by many nephrons which means that all nephrons function in ?

Answer 20

parallel

Question 21

filtration barrier in nephron consists of what 3 layers

Answer 21

1. capillary endothelium
2. glomerular basement membrane (basal lamina)
3. visceral epithelial cells (podocytes)

Question 22

podocytes

Answer 22

visceral epithelial cells

Question 23

pedicels

Answer 23

extensions of podocytes

Question 24

through what does filtrate flow to get into bowman’s capsule

Answer 24

slits between podocytes

Question 25

juxtaglomerular apparatus is composed of what 3 cell types

Answer 25

* macula densa * extraglomerular mesangial cells * granular cells (aka juxtaglomerular cells)

Question 26

function of juxtaglomerular apparatus

Answer 26

* helps control GFR * controls renin secretion (blood pressure and blood volume)

Question 27

mesangial cells

Answer 27

cells between capillary loops that contract in response to angiotensin II

Question 28

two arterioles of nephron

Answer 28

the afferent arteriole feeds the glomerular capillary bed while the efferent arteriole drains it.

Question 29

peritubular capillary bed consists of what two sections

Answer 29

1. cortical 2. vasa recta * supply blood to the nephron

Question 30

vasa recta

Answer 30

* _peritubular_ capillary bed that follows LOH * supplies nutrients to medullary tissue and important for recovery of water

Question 31

cortical arteries give off afferent arterioles, fluid not filtered goes into what arterioles?

Answer 31

efferent arteriole

Question 32

how many afferent arterioles are there per one glomerulus

Answer 32

one

Question 33

two capillary beds that supply blood to nephrone

Answer 33

* glomerular * peritubular

Question 34

the two arterioles (afferent and efferent) and two capillary beds (glomerular and peritubular) are connected in _?_

Answer 34

series

Question 35

renal nerves have what innervation?

Answer 35

sympathetic * \*\*parasympathetic innervation is absent

Question 36

renal nerves release what neurotransmitters

Answer 36

* NE * dopamine

Question 37

what receptors are present on afferent and efferent arterioles

Answer 37

alpha 1 receptors * \*primarily on _afferent_ arterioles

Question 38

stimulation of the renal nerve via the sympathetic nervous system tends to have what effect on Renal blood flow and GFR?

Answer 38

Renal blood flow and GFR are reduced

Question 39

simulataneous release of what prostaglandins with SNS stimulation keeps reductions of RBF and GFR minimized

Answer 39

* PGE₂ * PGI₂

Question 40

granular cells (juxtaglomerular) cells are innervated by SNS, stimulation of what receptors on these cells releases renin?

Answer 40

beta receptors

Question 41

normal GFR

Answer 41

120-125 ml/min

Question 42

tubular reabsorption

Answer 42

from renal tubular lumen to peritubular capillary

Question 43

tubular secretion

Answer 43

from peritubular capillary to tubular lumen