Topic 1 Part C Flashcards

1
Q

Regulation – Tubular Reabsorption (5)

A

Glomerulotubular balance
Peritubular Capillary & interstitial forces
Arterial blood pressure
Hormonal control
Sympathetic nervous effect
–Reabsorption of some solutes can be controlled independently

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2
Q

Glomerulotubular Balance

Allows an increase in reabsorption rate when there is an increase in

A

tubular load (increased tubular inflow)

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3
Q

Glomerulotubular Balance

If GFR went from 125 mls/minute to 150 mls/minute rate of reabsorption in proximal tubule would go from

A

81 mls/minute [65% of GFR] to 97.5 mls/minute [65% of GFR]

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4
Q

Glomerulotubular Balance
Works to maintain ____ and _____ homeostasis
-Prevents ____ changes in fluid flow to _____ even though there have been significant changes in _____

A

Works to maintain sodium and volume homeostasis

-Prevents large changes in fluid flow to distal tubules even though there have been significant changes in MAP

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5
Q

Peritubular Capillary & Interstitial Forces

Relationship of hydrostatic and oncotic pressures AND

A

filtration coefficient

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6
Q

Peritubular Capillary & Interstitial Forces
Normal – net force for reabsorption of ___ mmHg
Normal rate of ____ mls/minute

A

Normal – net force for reabsorption of 10 mmHg

Normal rate of 124 mls/minute

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7
Q

Peritubular Capillary & Interstitial Forces
____ filtration coefficient
-Reabsorption rate / net force
-Affected by ______ & ______ (permeability)
124 mls/min / 10 mmHg = ____ mls/min/mmHg

A

Large filtration coefficient
-Reabsorption rate / net force
-Affected by transfer surface area & hydraulic conductivity (permeability)
124 mls/min / 10 mmHg = 12.4 mls/min/mmHg

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8
Q

Peritubular hydrostatic pressure (PHP)

increase PHP =

A

decrease Reabsorption

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9
Q

Factor effecting Peritubular hydrostatic pressure

A

Arterial pressure

Resistance of afferent & efferent arteriole

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10
Q

increase AP – increase PHP – _____ reabsorption

A

decrease

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11
Q

increase resistance – decrease PHP – ___ reabsorption

A

increase

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12
Q

Peritubular oncotic pressure (POP)

[increase POP - Reabsorption]

A

increase

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13
Q

factors effecting Peritubular oncotic pressure

A
Plasma protein concentration
Filtration fraction (GFR/RPF)
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14
Q

increase plasma protein concentration – increase plasma oncotic pressure – increase POP – _____ reabsorption

A

increase

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15
Q

increase GFR or decrease RBF causes an increase filtration fraction
increase filtration fraction – increase protein concentration (more fluid is actually filtered) – increase POP – _____ reabsorption

A

increase

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16
Q

Factors Affecting Peritubular Capillary Reabsorption

Renal interstitial hydrostatic and colloid osmotic pressures are affected by changes in

A

reabsorptive forces of peritubular capillaries

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17
Q

Factors Affecting Peritubular Capillary Reabsorption
A decrease in capillary reabsorption…
-PRODUCES____ in interstitial solute AND interstitial water
-PRODUCES ____ in interstitial hydrostatic pressure AND _____ in interstitial oncotic pressure
-PRODUCES _____ in net movement (i.e. reabsorption) of solute & water from renal tubules to renal interstitial spaces

A
  • PRODUCES increase in interstitial solute AND interstitial water
  • PRODUCES increase in interstitial hydrostatic pressure AND decrease in interstitial oncotic pressure
  • PRODUCES decrease in net movement (i.e. reabsorption) of solute & water from renal tubules to renal interstitial spaces
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18
Q

Interstitial Hydrostatic & Oncotic Pressures

Under normal reabsorptive conditions there is always backflow of water & solute from

A

interstitial spaces to tubular lumen (tight junctions not very tight especially in proximal tubule)

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19
Q

Interstitial Hydrostatic & Oncotic Pressures
A decrease in Peritubular reabsorption -
_____ solute & water accumulation in interstitial space
_____ backflow of solute and water from interstitial space into tubular lumen

A

Increase solute & water accumulation in interstitial space
Increase backflow of solute and water from interstitial space into tubular lumen

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20
Q

Interstitial Hydrostatic & Oncotic Pressures

Forces that increase peritubular capillary reabsorption also increase

A

movement of solute and water (reabsorption) from the tubular lumen to the renal interstitial spaces [Reverse also true]

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21
Q

Factors Affecting Peritubular Capillary Reabsorption

A

Capillary surface area

Capillary permeability

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22
Q
Filtration Coefficient (FC) 
[Increase FC - \_\_\_\_\_ Reabsorption]
A

increase

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23
Q

increase surface area – increase FC – ___ reabsorption

A

increase

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24
Q

increase permeability – increase FC –____ reabsorption

A

increase

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25
Q

Factors Affecting Peritubular Capillary Reabsorption:

Coefficient remains constant under most physiologic conditions but will be affected by

A

renal disease

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26
Q
Arterial Pressure (Pressure Natriuresis/Diuresis): 
Even though autoregulation works to keep GFR and RBF constant as pressure changes (75 mmHg to 160 mmHg), there is a small increase in GFR which results in
A

an increase in urine output

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27
Q
Arterial Pressure (Pressure Natriuresis/Diuresis): 
As arterial pressure increases there is a small
A

decrease in the amount of sodium & water reabsorbed

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28
Q
Arterial Pressure (Pressure Natriuresis/Diuresis): 
Small increase in peritubular capillary hydrostatic pressure with subsequent
A

increase in renal interstitial hydrostatic pressure and increase backflow of solute and water

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29
Q

Arterial Pressure (Pressure Natriuresis/Diuresis):
As arterial pressure increased angiotensin II release is __
-Less stimulation of sodium reabsorption by _______
-Less stimulation of _____ production which means less stimulation of sodium reabsorption

A

As arterial pressure increased angiotensin II release is decreased

  • Less stimulation of sodium reabsorption by angiotensin II
  • Less stimulation of aldosterone production which means less stimulation of sodium reabsorption
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30
Q

Hormonal Control

Kidneys must be able to respond to changes in intake of specific substances without changing

A

output of the substances

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31
Q

Hormonal Control

Hormone secretion provides the control specificity needed to maintain normal

A

body fluid volumes and solute concentrations

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32
Q

Hormone: Aldosterone
Site of Action:
Effects:

A

Site of Action: Collecting tubule & duct
Effects: Increase NaCl, H2O reabsorption
Increase K+ secretion

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33
Q

Hormone: Angiotensin II
Site of Action:
Effects:

A

Site of Action: Proximal tubule; Thick ascending loop of Henle / distal tubule; Collecting duct
Effects: Increase NaCl, H2O reabsorption
Increase K+ secretion

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34
Q

Hormone: ADH
Site of Action:
Effects:

A

Site of Action: Distal tubule; Collecting tubule & duct

Effects: Increase H2O reabsorption

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35
Q

Hormone: Atrial Naturetic Pepetide
Site of Action:
Effects:

A

Site of Action: Distal tubule; Collecting tubule & duct

Effects: Decrease NaCl reabsorption

36
Q

Hormone: Parathyroid Hormone
Site of Action:
Effects:

A

Site of Action: Proximal tubule; Thick ascending loop of Henle; Distal tubule
Effects: Decrease PO4— reabsorption
Increase Ca++ reabsorption

37
Q

Aldosterone

  • Secreted by ______ cell in ______
  • Regulate _____ reabsorption and ______ secretion
  • Very important regulator of _______
A
  • Secreted by zona glomerulosa cell in adrenal cortex
  • Regulate sodium reabsorption and potassium secretion
  • Very important regulator of [potassium]
38
Q

Aldosterone

  • Principal site of action is ____ cells of ______
  • Stimulates increased ____ activity (_______ locations)
  • Increases permeability of ____ side membrane to _____
A
  • Principal site of action is principal cells of cortical collecting tubule
  • Stimulates increased Na-K ATPase activity (basolateral locations)
  • Increases permeability of luminal side membrane to sodium
39
Q

Aldosterone
Increased release stimulated by:
-Increased extracellular ______ concentration
-Increased ______ levels (i.e. sodium / volume depletion or low arterial pressure)

A

Increased release stimulated by:

  • Increased extracellular potassium concentration
  • Increased angiotensin II levels (i.e. sodium / volume depletion or low arterial pressure)
40
Q

Aldosterone
Pathophysiology
-Absence=
-Excess=

A

Pathophysiology

  • Absence (adrenal malfunction or destruction) (Addison’s disease)
  • Excess (adrenal tumors) (Conn’s syndrome)
41
Q

Angiotensin II

  • Most powerful ________ hormone
  • Increased production caused by _____ and/or ______
A
  • Most powerful sodium-retaining hormone

- Increased production caused by low blood pressure and/or low ECF volume

42
Q

Angiotensin II

Stimulates ______ secretion (increased sodium reabsorption)

A

aldosterone

43
Q

Angiotensin II

  • Constricts _______ (increase sodium and water reabsorption)
  • Helps ensure that normal exertion rates of ______ are maintained by helping to maintain normal rates of _____
  • Able to retain ______ without retaining_________
A
  • Constricts efferent arterioles (increase sodium and water reabsorption)
  • Helps ensure that normal exertion rates of metabolic wastes are maintained by helping to maintain normal rates of GFR
  • Able to retain sodium & water without retaining metabolic waste
44
Q

Angiotensin II

  • Direct stimulation of sodium reabsorption in (4)
  • Stimulate increased ______ of tubular epithelial cells (____ membrane)
  • Stimulate _____ exchange in _______ (_____ membrane)
  • Stimulate ______ co-transport (_________ membrane)
A
  • Direct stimulation of sodium reabsorption in proximal tubules, loop of Henle, distal tubules, and collecting tubules
  • Stimulate increased Na-K ATPase activity of tubular epithelial cells (basolateral membrane)
  • Stimulate Na-H exchange in proximal tubule (luminal membrane)
  • Stimulate Na-Bicarb co-transport (basolateral
45
Q

Angiotensin II

Affects transport on both ____ and _____ membranes

A

luminal and basolateral

46
Q

Angiotensin II

Very active in ______ but also effective in (3)

A

Very active in proximal tubule but also effective in loop of Henle, distal tubule, collecting tubule

47
Q
Antidiuretic Hormone (Vasopressin)
made in the
A

hypothalamus

48
Q
Antidiuretic Hormone (Vasopressin)
Two types of \_\_\_\_\_\_\_ neurons produce ADH
-Neurons located in \_\_\_\_ and \_\_\_\_\_\_ nuclei
-\_\_% in supraoptic
-\_\_% in paraventricular nuclei
A

Two types of magnocellular (large) neurons produce ADH

  • Neurons located in supraoptic and paraventricular nuclei
  • 83% in supraoptic
  • 17% in paraventricular nuclei
49
Q
Antidiuretic Hormone (Vasopressin)
Once produced ADH moves down the neurons to their tips which are located in the \_\_\_\_\_ and is released
A

posterior pituitary

50
Q
Antidiuretic Hormone (Vasopressin)
Stimulation of the supraoptic and paraventricular nuclei (increased \_\_\_\_\_\_) sends impulses down the \_\_\_\_\_\_\_ neurons which stimulates release of ADH from \_\_\_\_\_\_ located in the nerve endings
A

Stimulation of the supraoptic and paraventricular nuclei (increased osmolarity) sends impulses down the magnocellular neurons which stimulates release of ADH from storage vesicles located in the nerve endings

51
Q
Antidiuretic Hormone (Vasopressin)
Controls water permeability of (3)
A

distal tubule, collecting tubule, and collecting duct

52
Q
Antidiuretic Hormone (Vasopressin)
Decrease [ADH] results in \_\_\_\_\_ water permeability so water is not reabsorbed which results in \_\_\_\_\_ urine volume and \_\_\_\_\_ [solute] = large volumes of dilute urine
A

Decrease [ADH] results in decrease water permeability so water is not reabsorbed which results in increase urine volume and increase [solute] = large volumes of dilute urine

53
Q
Antidiuretic Hormone (Vasopressin)
Stimulates formation of water channels across
A

luminal membrane

54
Q
Antidiuretic Hormone (Vasopressin)
Binds with specific V2 receptors which increases formation of
A

cyclic AMP and activation of protein kinases

55
Q
Antidiuretic Hormone (Vasopressin)
Protein kinase activation results in movement of
A

aquaporin-2 (intracellular protein) to luminal side of cell

56
Q
Antidiuretic Hormone (Vasopressin)
\_\_\_\_\_\_\_\_ come together and fuse with cell membrane to form water channels which increases membrane permeability to water (increase water reabsorption)
A

Aquaporin-2 molecules

57
Q
Antidiuretic Hormone (Vasopressin)
Chronic increases in ADH will stimulate an increase in
A

formation of aquaporin-2 molecules

58
Q
Antidiuretic Hormone (Vasopressin)
AVP =
A

arginine vasopressin

59
Q
Antidiuretic Hormone (Vasopressin)
V2 receptors on basolateral membranes so increase [ADH] in the plasma will result in movement of ADH from
A

peritubular capillaries to the renal interstitial space

60
Q

Antidiuretic Hormone (Vasopressin)
Other aquaporins are present on the basolateral membrane providing _____
-No evidence to show that they are affected by _____

A

Other aquaporins are present on the basolateral membrane providing water channels
-No evidence to show that they are affected by [ADH]

61
Q
Antidiuretic Hormone (Vasopressin)
Decrease [ADH] results in movement of the \_\_\_\_\_\_\_ back into the \_\_\_\_\_\_ which reduces the number of \_\_\_\_\_ channels and decrease water \_\_\_\_\_\_\_\_\_\_
A

Decrease [ADH] results in movement of the aquaporin-2 molecules back into the cytoplasm which reduces the number of water channels and decrease water permeability

62
Q

Atrial Natriuretic Peptide

Secreted by cardiac atrial cells when atria

A

distended by plasma volume expansion

63
Q

Atrial Natriuretic Peptide

  • Direct inhibition of _____ & _____ reabsorption (especially collecting ducts)
  • Inhibits ____ secretion (thus inhibits ______ formation)
A
  • Direct inhibition of sodium & water reabsorption (especially collecting ducts)
  • Inhibits renin secretion (thus inhibits angiotensin II formation)
64
Q

Atrial Natriuretic Peptide

Important response to help prevent ________ during heart failure

A

sodium and water retention

65
Q

Parathyroid Hormone

Most important hormone for regulating

A

calcium

66
Q

Parathyroid Hormone

  • Increases _____ reabsorption (________)
  • Inhibits ______ reabsorption (______)
  • Increases _____ reabsorption (_________)
A
  • Increases calcium reabsorption (distal tubules)
  • Inhibits phosphate reabsorption (proximal tubule)
  • Increases magnesium reabsorption (loop of Henle)
67
Q

Sympathetic Nervous System

Severe stimulation results in constriction of

A

renal arterioles which decrease GFR

68
Q

Sympathetic Nervous System

Low levels of stimulation activate ______ on renal tubular epithelial cells (4)

A

Low levels of stimulation activate alpha-receptors on renal tubular epithelial cells (proximal tubule, thick ascending limb of loop of Henle, maybe distal tubule)

69
Q

Sympathetic Nervous System

Receptor activation stimulates sodium reabsorption which

A

decreases sodium and water excretion

70
Q

Sympathetic Nervous System

Stimulates release of renin (angiotensin II) which adds to

A

increase in tubular reabsorption of sodium

71
Q

Renal Clearance=

A

Volume of plasma that is completely cleared (i.e. all of specified solute) by kidneys per unit time

72
Q

Renal Clearance allows us to quantify (5)

A
excretory function of kidneys
renal blood flow
glomerular filtration
tubular reabsorption
tubular secretion
73
Q

Renal Clearance= [formula]

A

Cs= Us*V / Ps

Urinary excretion rate / Plasma concentration

74
Q

Estimation of GFR

If solute freely filtered and neither reabsorbed or secreted, then excretion rate is the

A

filtration rate

75
Q

Estimation of GFR

A four fold increase in creatinine concentration means the GFR is

A

one-fourth normal

76
Q

Estimation of GFR= [formula]

A

GFR * Ps= Us * V= Us*V / Ps= Cs

77
Q

Estimation of Renal Plasma Flow

If a substance is completely cleared then clearance rate should equal the

A

renal plasma flow

78
Q

Estimation of Renal Plasma Flow

PAH clearance provides reasonable estimation of

A

renal plasma flow (90% cleared)

79
Q

Estimation of Renal Plasma Flow

Actual renal plasma flow can be calculated by dividing the PAH clearance rate by the PAH extraction rate=

A

PAH Clearance / 0.9

80
Q

Estimation of Renal Plasma Flow

TOTAL BLOOD FLOW can be calculated by taking the calculated plasma flow and dividing

A

by (1-HCT)

81
Q

Filtration Fraction = [formula]

A

GFR / RPF

82
Q

Absorption= [formula]

A

Filtered load – Excretion rate

83
Q

Secretion= [formula]

A

Excretion rate – Filtered load

84
Q

If equal to inulin clearance then…

A

Substance only filtered, not reabsorbed, not secreted

85
Q

If less than inulin clearance then…

A

Substance must be reabsorbed

86
Q

If greater than inulin clearance then…

A

Substance must be secreated