Exam 3: Salt/water Balance Flashcards Preview

Endocrinology > Exam 3: Salt/water Balance > Flashcards

Flashcards in Exam 3: Salt/water Balance Deck (93)
Loading flashcards...
1
Q

Osmolarity of ECF is monitored/adjusted by

A

Regulating water excretion in kidney in response to ADH

2
Q

Major electrolyte in ECF

A

Na+

3
Q

Renal mechanisms of Na+ balance

A

RAAS

Atrial natriuretic peptide

4
Q

ADH contributes ___ to volume regulation

A

Directly

**Trumps osmolarity

5
Q

Virtually all Na+ reabsorption in kidney is due to

A

Passive Na+ reabsorption following gradient

Active Na+ removal due to ATPase

6
Q

Na+ coupled transport also reabsorbs

A

Glucose
AA
Phosphate
HCO3

(Water follows)

7
Q

H2O is impermeable across

A

Ascending loop of Henle

8
Q

Hormones that regulate NaCl/H2O

A

Antidiuretic hormone
RAAS
ANP

9
Q

ADH AKA

A

Vasopressin

10
Q

ADH signals kidney to

A

Conserve H2O

11
Q

ADH is released when

A

Plasma osmolarity inc

Plasma volume dec 10-15%

12
Q

Osmole receptors are very sensitive and ___% inc can stim ADH release

A

1-2%

13
Q

Blood volume changes are sensed by _____ receptors

A

High and low pressure receptors

14
Q

Response to ___ volume is an emergency response

A

Dec

15
Q

ADH is a powerful vaso____ which targets

A

Constrictor; arteriolar smooth muscle (V1 receptor)

16
Q

ADH via V2 receptor causes

A

Insertion of aquaporins

17
Q

Aquaporins are H2O channels that

A

Make collecting duct permeable to H2O

18
Q

Osmole receptors are found in

A

Circumventricular organs

  • organum vasculosum
  • subfonical organ
19
Q

Axons from circumventricular organs project to ADH producing cells in

A

Hypothalamic supraoptin and paraventricular nuclei

20
Q

Most potent osmolyte

A

NaCl

21
Q

Dehydration and ADH

A

Inc osmolarity and dec volume stimulate ADH

22
Q

Dec osmolarity and small dec in volume

A

Osmolarity kept constant

23
Q

Dec osmolarity and LARGE dec in volume

A

Osmolarity sacrificed to maintain integrity of ciruclation

24
Q

Diabetes insipidis

A

Large amounts of dilute urine

25
Q

Central diabetes insipidis

A

Dec ADH production

Low circulating ADH

26
Q

Nephrogenic diabetes insipidis

A

Dec response of kidney to ADH

Circulating ADH levels high

27
Q

Syndrome of inappropriate ADH

A

Inc ADH secretion even if plasma osmolarity low

28
Q

Syndrome of inappropriate ADH death occurs when

A

Profound dilution of plasma electrolytes

29
Q

ADH cell bodies found in

A

Supraoptic nuclei

30
Q

Oxytocin cell bodies found in

A

Paraventricular nuclei

31
Q

ADH and oxytocin are secreted from nerve terminals in

A

Posterior pituitary

32
Q

Supraoptic nuclei can make both

A

Oxytocin and ADH

33
Q

ADH acts on principal cells in last ___ to inc H2O reabsorption, thus ___ body fluid osmolarity

A

DCT; dec (back to normal)

34
Q

V2 receptor for ADH elicits response via

A

cAMP

35
Q

CAMP causes insertion of aquaporin 2 which ____ the urine

A

Concentrates

36
Q

V1 receptor is coupled to

A

Phospholipase C

37
Q

Net result of ADH w/ V1 receptor

A

Contraction of vascular SM
Constrict arterioles
Inc TPR

38
Q

Thiazide diuretics are used to treat

A

Nephrogenic diabetes insipidus

39
Q

Thiazide diuretics ___ Na+ reabsorption in distal tubule

A

Inhibit

40
Q

Thiazide diuretics ___ GFR

A

Dec

Less H2O filtered—less excreted

41
Q

Thiazide diuretics can cause a secondary ____ due to inc Na+ excretion

A

ECF volume contraction

42
Q

Renin is a hormone synthesized/secreted by

A

Juxtaglomerular cells in renal arterioles

43
Q

Renin stimulated by

A

SNS activation

Dec tension/pressure in glomerulus

44
Q

Dec pressure in glomerulus can ___ rate of NaCl delivery to macula densa

A

Dec

45
Q

Renin catalyzes formation of ____ from ___

A

Angiotensin I; angiotensinogen

46
Q

Angiotensin I is the ____ form

A

Inactive

47
Q

Angiotensin I is converted to angiotensin II by ___ in the ____

A

ACE; liver

48
Q

Angiotensin II is also produced locally in

A

BV
Adipose
Brain

49
Q

Angiotensin II may act locally as a paracrine to

A

Stim prostaglandins

Act as local growth factor

50
Q

Angiotensin II is the primary signal for the release of

A

Aldosterone

51
Q

Angiotensin II also causes vasoconstriction in the kidney which

A

Dec renal blood flow and glomerular filtration

52
Q

Constriction of the EA by angiotensin II ___ colloid pressure in peritubular caps which ____ reabsorption

A

Inc; inc

53
Q

Angiotensin effect on cardiac contractility

A

Inc

54
Q

Angiotensin inc blood flow to ___ and dec blood flow to ___

A

Inc: heart, brain, skeletal muscle

Dec: skin, viscera

55
Q

One of the most potent pressor substance known

A

Angiotensin II

56
Q

Angiotensin II in CNS stimulates _______ and secretion of ___

A

Stims thirst and appetite for Na+

Stims secretion of ADH

57
Q

Angiotensin II in hypothalamic cells project to

A

Supraoptic and paraventricular N

Vasomotor centers

58
Q

Angiotensin II stim in paraventricular nuclei

A

Release ADH

59
Q

Major regulator of RAAS

A

Negative feedback

60
Q

Blood volume ___ as a result of sodium retention

A

Inc

61
Q

ANP promotes excretion of

A

Sodium in urine

62
Q

ANP synthesized and secreted from

A

Atrial myocytes

63
Q

Two other forms of ANP

A

BNP (brain)

CNP (CNS)

64
Q

ANP/BNP binds to which receptor

A

Natriuretic peptide receptor-A (NPR-A)

65
Q

CNP binds to which receptor

A

NPR-B

66
Q

All three hormones (ANP/BNP/CNP) bind to which receptor

A

NPR-C

67
Q

NPR-C may function as

A

Clearance receptor — removes ANP/BNP/CNP from blood

68
Q

ANP and BNP both stim formation of

A

Cyclic GMP

69
Q

Cyclic GMP modifies cellular functions via 3 mechanisms

A
  1. Phosphorylation of proteins
  2. Cyclic nucleotide phodphodiesterases
  3. Ion channel regulation
70
Q

ANP acts on these organs ___ to lower _______

A

CN system
Kidneys
Adrenal glands
CNS

Lower blood volume and pressure

71
Q

ANP on CV system

A

Vasodilation of vascular SM

72
Q

ANP in the kidney inc Na+ and H2O excretion by inc ____ and dec Na+ and H2O reabsorption

A

Glomerular filtration

73
Q

ANP causes ___ renin secretion

A

Dec

74
Q

ANP effects on hypothalamus

A

Dec ADH secretion
dec vasomotor activity
Inhibits thirst
Dec Na+ appetite

75
Q

ANP in pituitary gland inhibits release of

A

ACTH (causes dec adrenal support)

76
Q

ANP on adrenal gland

A

Dec aldosterone secretion

77
Q

ANP effect on SNS

A

Dec NE/epi release

78
Q

Hemorrhage effect on osmolarity

A

No change

79
Q

Immediate response to hemorrhage

A

Vasoconstriction mediated by SNS

80
Q

Slower response to hemorrhage

A

RAAS

81
Q

Hemorrhage stims ___ and inhibits ___

A

ADH; ANP

82
Q

Dehydration

A

H2O loss > solute loss

83
Q

Dehydration effect on osmolarity

A

Inc in ECF/ICF osmolarity

84
Q

Primary way to correct dehydration

A

ADH — promotes H2O reabsorption w/out reabsorbing solute

85
Q

Dehydration ___ ANP

A

Inhibits

86
Q

Salt loading promotes ____ of Na+ in urine

A

Excretion

87
Q

Salt depletion minimizes _____ of Na+ in urine

A

Excretion

88
Q

Salt loading causes ___ ANP and ADH

A

Inc

89
Q

Salt loading causes ____ in plasma osmolarity

A

Slight inc

90
Q

Salt depletion causes ___ in ANP and ADH

A

Dec

91
Q

Salt depletion ___ plasma osmolarity

A

Slight dec

92
Q

High salt intake suppresses ____ and slight increase in osmolarity stims ___

A

RAAS; ADH

93
Q

Low salt intake stims release of ____ and slight decrease in osmolarity inhibits ____

A

RAAS; ADH