Renal 2

Question 1

micturition reflex

Answer 1

increase volume of fluid in bladder, expansion of wall, stretch receptors activated, increase parasymp activity, contraction of detrusor muscle, relaxating of internal urethral sphincter

Question 2

incontinence

Answer 2

inability to control urination voluntarily

Question 3

how is dilute urine produced

Answer 3

distal nephron must reabsorb solute without allowing water to follow by osmosis (aquaporins)

Question 4

how is concentrated urine produced

Answer 4

distal nephron must reabsorb water and little solute

Question 5

how is water absorbed without solute

Answer 5

make interstitial fluid more concentrated than fluid flowing into tubule

Question 6

what happens at the descending limb of loop of henle

Answer 6

only water is reabsorbed because of the concentrated interstitial space

Question 7

what happens at the ascending loop of henle

Answer 7

solutes are removed from tubule creating hyposmitic fluid in tubule
- has apical surfaces that are impermeable to water so water doesn’t follow out solute

Question 8

vasopressin

Answer 8

posterior pituitary hormone helps add or remove water pores in the apical membrane

Question 9

how do distal tubule and colelcting duct alter permeability to water

Answer 9

vasopressin

Question 10

absense of vasopressin

Answer 10

collecting duct is impermeable to water and urine is dilute

Question 11

maximal vasopressin secretion

Answer 11

collecting duct is freely permeable to water. water leaves via osmosis and is carried away by vasa recta

Question 12

vasopressin and aqp2 insertion

Answer 12

vasopressin causes insertion of aqp2 channels on apical membrane

Question 13

steps of vasopressin insertion into apical membrane

Answer 13

diagram

Question 14

what factors control vasopressin secretion

Answer 14

• increased osmolarity*
• bp
• blood volume

Question 15

osmoreceptors

Answer 15

stretch sensitive neurons that increase firing rate as osmolarity increases (shrink)

Question 16

renal countercurrent exchange system components

Answer 16

• counter current multiplier - loop of henle

- countercurrent exchanger - peritubular capillaries

Question 17

countercurrent multiplier

Answer 17

• descending limb - water follows its osmotic gradient into the increasing hypertonic interstitium but no solutes are transported
• ascending limb - transports solutes into interstitum (not permeable to water)

Question 18

countercurrent exchanger

Answer 18

vasa recta of juxtamedullary nephrons are responsible for the high osmolarity deep in the medulla

Question 19

active transport in the ascending loop of henle

Answer 19

1. NKCC transporters on apical membrane use energy stored to move Na, K, 2 Cl- into epithelial cells
2. water doesn’t follow
3. Na is transported against [] gradient on basolateral membrane

Question 20

where does majority of reabsorption take place

Answer 20

proximal tubule

Question 21

what is the main job of the countercurrent multiplier

Answer 21

create the hypertonic interstitium

Question 22

what is the main job of the countercurrent exchanger

Answer 22

prevent the washout (dilution) of the hypertonic interstitium

Question 23

what is urea’s role in the high slute concentration in the medulla

Answer 23

area is reabsorbed in the distal portion and is always moving through the medulla

Question 24

high AVP increases AQP2

Answer 24

increased reabsorption

Question 25

low AVP = decreased AQP2

Answer 25

reduced reabsorption

Question 26

aldosterone

Answer 26

a steroid that stimulates Na+ reabsorption and K+ secretion in the kindey - last third of the collecting duct in cortex

Question 27

what regulates blood Na+ level

Answer 27

renin-angiotensin-aldosterone system

Question 28

adolesterone acting on principle cells

Answer 28

1. aldosterone binds on basolateral side of membrane 2. something happens with transcription 3. new protein channel made on apical membrane 4. pumps on existing membranes go faster to increase Na+ reabsorption - increases number of Na/K transporters on the basolateral membrane of the distal tubule and collecting ducts

Question 29

what controls aldosterone secretion

Answer 29

low blood pressure and increased ecf concentration of K+

Question 30

decreased blood pressure causes an increased release of ____

Answer 30

angiotensin II

Question 31

angiotensin II production triggers the release of _____

Answer 31

aldosterone produced by adrenal cortex

Question 32

(modifieres of aldosterone release) | increased osmolarity acts directly on the ___ during dehydration to ___ release

Answer 32

adrenal cortex; inhibit

Question 33

factors that secrete renin

Answer 33

1. low blood pressure in arterioles 2. sympathetic neurons activated by CVCC when blood pressure is low 3. paracrine feedback from macula densa cells signal the granular cells to secrete renin

Question 34

granular cells

Answer 34

secrete renin

Question 35

renin

Answer 35

converts angiotensinogen to angiotensin I

Question 36

ACE enzyme

Answer 36

converts angiotensin I to angiotensin II

Question 37

angiotensin II effects

Answer 37

- increase vasopressin secretion - stimulates thrist - vasoconstrictor - increase sympathetic output to heart and blood vessels - increases proximal tubule Na+ reabsorption

Question 38

atrial natriuretic peptide (ANP)

Answer 38

promotes Na+ and water excretion | -

Question 39

atrial natriuretic peptide (ANP)

Answer 39

promotes Na+ and water excretion - relaxes afferent arterioles - reduces renin release from granular cells - reduces Na+ reabsorption at the collecting duct