PSL301: Water 4 Flashcards Preview

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Flashcards in PSL301: Water 4 Deck (89):
0

sodium is required for...

normal blood volume, BP, organ perfusion

1

Early humans evolved in a ___ sodium environment

Low

2

Inadequate sodium results in...

- shock
- low ECF volume
- low BP

3

Human kidneys are designed to ____ sodium

retain

4

what happens when the kidneys retain sodium?

keep blood volume high / constant

5

Why is high blood pressure such a common problem nowadays?

Kidneys are designed to retain sodium, so now that we are getting a lot of Na in the diet, it leads to problems like hypertension

6

Possible ways to lose Na

- diarrhea
- sweating
- diuretics

7

We retain Na in conditions like...

heart failure

8

What happens if we have too much Na?

- edema / pulmonary edema
- weight gain
- breathing problems

9

Data for some populations suggest that low Na+ increases risk for...

deaths from cardio events

10

Which ethnicity is famous for high Na diet?

Japanese

11

Relationship between Na intake and risk of fatal stroke

Higher intake = higher risk for stroke

12

Where does dietary salt come from?

- 75% from processed foods
- bread, cheese, soup, sauces, restaurants
- very little from home cooking

13

Normally, urine sodium =

dietary intake of sodium

14

Urine sodium decreases if...

there is Na lost from gut (diarrhea) or skin (sweating)

15

Urine sodium decreases to 0 when...

there is severe loss from the gut or skin
e.g. cholera

16

What can be used to estimate Na intake?

24h urine collection

17

How long does it take for the kidneys to adjust to increase Na in the diet?

several days is needed to form a new steady state

18

what happens if there is a sudden increase in Na from the diet?

ECF volume is large for a few days until kidneys adjust

19

what happens if there is a sudden decrease in Na from the diet?

ECF volume is small for a few days until kidneys adjust

20

Dietary sodium is a high risk factor for...

- high BP
- stroke
- heart disease
- kidney disease

21

reducing Na intake is used as a form of treatment for...

- CHF
- cirrhosis with ascites
- kidney diseases
- diseases that result in edema (all of above)
- hypertension

22

What sends the kidney signals to increase / decrease Na exretion?

Signals from the vascular system
- intravascular volume
- effective circulating volume

23

What does not signal the kidneys to adjust Na levels?

serum [Na] concentration

24

What does serum [Na] affect?

- water balance
- ADH
??

25

What is effective circulating volume?

How well cardiac output fills the arterial system

26

When is effective circulating volume low?

- low intravascular volume
- poor heart function
- excessive arterial vasodilation

27

What is low effective circulating volume sensed by?

cardiovascular receptors
- arterial baroreceptors
- juxtaglomerular apparatus
- atrial stretch receptors

28

What are possible causes of low intravascular volume?

- diarrhea
- sweating
- hemorrhage

29

What are possible causes of poor heart function?

congestive heart failure

30

What are possible causes of excessive arterial vasodilation?

liver cirrhosis (advanced liver disease)

31

The glomerulus is enclosed by...

Bowman's capsule

32

Cells that make up the Bowman's capsule

granular cells

33

What goes out of the Bowman's capsule?

proximal tubule

34

What goes in and out of the glomerulus?

in: afferent arteriole
out: efferent arteriole

35

What lies beside the arterioles of the glomerulus?

ascending limb of Henle

36

What is the purpose of having the ascending limb beside the glomerulus?

allow glomerulus to sense things inside the ascending limb
- feedback regulation
- affect filtration rate, Na retention, etc. of glomerulus

37

What cells make up the ascending limb that lie next to the glomerulus arterioles?

macula densa cells

39

what are macula densa cells?

- reabsorptive cells that sense NaCl levels
- sends signals to the glomerulus
- regulates GFR

40

purpose of renin

angiotensinogen -> angiotensin I

41

what is the rate limiting step of the RAAS?

renin

42

angiotensin I

small, inactive AA

43

where can ACE be found?

on endothelial lining of pulmonary capillaries

44

ANG II has what effect?

- increase BP
- increase blood volume
- maintain osmolarity

45

ANG II: what does it do to cause increased BP?

- peripheral arterioles (efferent arteriole) vasoconstrict
- cardiovascular control center in medulla tells cardiovascular system to increase BP
- increased volume

46

where does ANG II affect?

- arterioles
- cardiovascular center in medulla
- hypothalamus
- adrenal cortex

47

effect of ANG II on hypothalamus

- release vasopressin (ADH)
- thirst
Overall: more fluid in vessels

48

effect of ANG II on adrenal cortex

release aldosterone

49

effect of aldosterone

increase Na+ reabsorption (used to maintain osmolarity)

50

ANG II stimulates Na+ reabsorption in...

- proximal tubule
- distal convoluted tubule
- collecting duct

51

How does the body make sure only the efferent arteriole is constricted by ANG II?

AT1 receptors are only present on efferent arterioles

52

what increases renin secretion?

- low afferent arteriole BP
- active SNS
- low dietary NA
- upright posture = more renin
- reduced ECF volume: diuretic therapy, diarrhea, sweating, blood loss
- reduced effective circulating volume (heart failure, liver cirrhosis)

53

what senses afferent arterole pressure?

- afferent arteriolar stretch
- macula densa

54

What senses pressure in the SNS?

baroreceptors

55

the RAAS has what effect on cardiac myocytes, arteries, mesangium?

release growth factor, which reduces compliance in arteries and kidneys

56

Mesangium

structure that can be found between the afferent & efferent arterioles.

surrounded by capillaries but outside of capillary lumen.

57

where is aldosterone secreted?

zona glomerulosa of adrenal cortex

58

aldosterone is a ___ hormone

steroid

59

receptor for aldosterone

mineralocorticoid receptor

60

where can the receptor for aldosterone be found?

cortical collecting duct (intracellular receptor)

61

mechanism of aldosterone

Changes protein synthesis
- increase Na channels (ENaC)
- increase opening of already present channels

62

effect of aldosterone

- Na reabsorption
- K excretion
- H excretion

63

ANP is secreted by... in response to...

atrial myocytes
atrial stretch (high BP)

64

function of ANP

- inhibits collecting duct Na reabsorption
- increase GFR

65

what does ANP inhibit?

- aldosterone
- SNS
- vasopressin
overall: inhibits collecting duct Na reabsorption

66

Factors that affect Na excretion

1. reduced GFR (small effect)
2. ANG II
3. aldosterone
4. ANP
and others not known yet

67

what causes decreased ECF volume?

1. sweating
2. diarrhea
3. vomiting
4. osmotic diuresis
5. diuretics
6. blood loss

68

how much Na is lost per L of sweat?

35 mmol/L

69

how much Na is lost per L of diarrhea?

100 - 120 mmol/L

70

bicarbonaturia

excretion of excessive amounts of bicarbonates in the urine

71

how much Na is in gastric fluid?

10 mM

72

Na loss in the urine is driven by...

bicarbonaturia
??

73

what states can be seen when there is an excess of sodium?

1. congestive heart failure
2. cirrhosis with ascites
3. kidney disease

74

congestive heart failure

low CO

75

why might congestive heart failure cause Na retension

low CO (low BP) stimulates Na retention

76

why might cirrhosis with ascites cause Na retension

low arterial resistance lowers effective circulating volume -> stimulates Na retension

77

ascites

the accumulation of fluid in the peritoneal cavity, causing abdominal swelling

78

side effects of congestive heart failures

edema, pulmonary edema

79

What effect does high Na have on the heart?

aggravates heart failure
- fibrosis
- oxygen demand
- reduces peripheral perfusion

80

What drugs can be used to treat heart failure caused by high Na?

- ACE inhibitors
- angiotension receptor blockers
- aldosterone blocker

81

ACE inhibitor drug

ramipril (-pril)

82

angiotension receptor blockers drug

losartan (-artan)

83

aldosterone blocker drug

spironolactone

84

ramipril, losartan, and spironolactone can be used to treat...

- congestive heart failure
- hypertension
- slow progression of chronic kidney disease
- reduce protein loss in CKD

85

How to treat someone who has extremely low ECF due to high Na loss?

- IV sodium and water
- isotonic saline
- give something to drink: has salt, glucose, K, alkali

86

isotonic saline is...

150 mmol/L of Na in water

87

What does the WHO have to treat those who have severe diarrhea?

oral rehydration fluid:
- NaCl
- glucose
- KCl
- sodium citrate

88

why is glucose included in oral rehydration fluid?

Na is absorbed through SGLT 1 with glucose

89

antagonizing RAAS has major benefits in...

cardiovascular and kidney disease