Renal 2 Flashcards

1
Q

micturition reflex

A

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

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2
Q

incontinence

A

inability to control urination voluntarily

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3
Q

how is dilute urine produced

A

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

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4
Q

how is concentrated urine produced

A

distal nephron must reabsorb water and little solute

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5
Q

how is water absorbed without solute

A

make interstitial fluid more concentrated than fluid flowing into tubule

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6
Q

what happens at the descending limb of loop of henle

A

only water is reabsorbed because of the concentrated interstitial space

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7
Q

what happens at the ascending loop of henle

A

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

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8
Q

vasopressin

A

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

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9
Q

how do distal tubule and colelcting duct alter permeability to water

A

vasopressin

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10
Q

absense of vasopressin

A

collecting duct is impermeable to water and urine is dilute

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11
Q

maximal vasopressin secretion

A

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

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12
Q

vasopressin and aqp2 insertion

A

vasopressin causes insertion of aqp2 channels on apical membrane

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13
Q

steps of vasopressin insertion into apical membrane

A

diagram

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14
Q

what factors control vasopressin secretion

A
  • increased osmolarity*
  • bp
  • blood volume
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15
Q

osmoreceptors

A

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

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16
Q

renal countercurrent exchange system components

A
  • counter current multiplier - loop of henle

- countercurrent exchanger - peritubular capillaries

17
Q

countercurrent multiplier

A
  • 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)
18
Q

countercurrent exchanger

A

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

19
Q

active transport in the ascending loop of henle

A
  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
20
Q

where does majority of reabsorption take place

A

proximal tubule

21
Q

what is the main job of the countercurrent multiplier

A

create the hypertonic interstitium

22
Q

what is the main job of the countercurrent exchanger

A

prevent the washout (dilution) of the hypertonic interstitium

23
Q

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

A

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

24
Q

high AVP increases AQP2

A

increased reabsorption

25
Q

low AVP = decreased AQP2

A

reduced reabsorption

26
Q

aldosterone

A

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

27
Q

what regulates blood Na+ level

A

renin-angiotensin-aldosterone system

28
Q

adolesterone acting on principle cells

A
  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
29
Q

what controls aldosterone secretion

A

low blood pressure and increased ecf concentration of K+

30
Q

decreased blood pressure causes an increased release of ____

A

angiotensin II

31
Q

angiotensin II production triggers the release of _____

A

aldosterone produced by adrenal cortex

32
Q

(modifieres of aldosterone release)

increased osmolarity acts directly on the ___ during dehydration to ___ release

A

adrenal cortex; inhibit

33
Q

factors that secrete renin

A
  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
34
Q

granular cells

A

secrete renin

35
Q

renin

A

converts angiotensinogen to angiotensin I

36
Q

ACE enzyme

A

converts angiotensin I to angiotensin II

37
Q

angiotensin II effects

A
  • increase vasopressin secretion
  • stimulates thrist
  • vasoconstrictor
  • increase sympathetic output to heart and blood vessels
  • increases proximal tubule Na+ reabsorption
38
Q

atrial natriuretic peptide (ANP)

A

promotes Na+ and water excretion

-

39
Q

atrial natriuretic peptide (ANP)

A

promotes Na+ and water excretion

  • relaxes afferent arterioles
  • reduces renin release from granular cells
  • reduces Na+ reabsorption at the collecting duct