PSL301: Water 1 Flashcards Preview

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Flashcards in PSL301: Water 1 Deck (72):
1

Functions of the kidney (3)

1. Maintain normal volume & composition in the body
2. Excrete waste from body
3. Maintain BP, hemoglobin, Ca++ levels through hormone secretion

2

What is the main waste secreted by the kidneys?

Products of protein metabolism

3

How does the kidney maintain normal volume & composition in the body?

filter large volumes of plasma, water, solutes at the glomerulus

4

The kidney clears ___x the total plasma volume every day

40

5

How does the kidney Excrete waste from body?

filtered fluid goes through tubules: add or remove water & solutes to form final urine product

6

How does the kidney Maintain BP, hemoglobin, Ca++ levels?

Secretes hormones in response to changes in BP, hemoglobin, Ca++

7

Case: slow marathon runner with headache, nausea, vomit, grand mal seizure, hyponatremia

What's wrong?

Cells in brain swell due to hyponatremia:
- increase intracranial pressure; parts of brain get compressed
- seizure, coma, death

8

Case: slow marathon runner with headache, nausea, vomit, grand mal seizure, hyponatremia

How to treat?

Give IV (hypertonic saline solution)
- raise Na+ in ECF
- water move out of brain cells

9

define: solutes

particles dissolved in a water solution

10

define: electrolytes

charged solutes

11

define: osmolarity

concentration of solutes in water which generates an osmotic force

12

define: osmosis

movement of water across semi-permeable membrane in response to an osmotic gradient

13

Water moves from __ osmolality to __ osmolality

low
high

14

define: osmotic gradient

a difference in the osmolality in the compartments separated by the membrane

15

Humans are __ % water

50 - 60

16

Body water is split into...

1. intracellular space (2/3)
2. extracellular space (1/3)

17

ECF is split into...

Plasma (25%)
Interstitial fluid (75%)

18

What is ISF?

Fluid outside both the cell and the blood stream

19

Plasma is bordered by...
Cells are bordered by...

Capillary walls (endothelial cells)
Cell membrane

20

What factor determines body water as a fraction of weight?

Ratio of fat : muscle

21

__ contains most of the water in the body, while ___ has very little water.

Muscle
Fat

22

On average, the fat:muscle ratio is higher in...

- women
- older people
- sick people

23

Males are __% water, while females are __%

60
50

24

Why do males have more water than females?

They have more muscle

25

What solutes are present in body fluids?

- ions/electrolytes
- fuels
- proteins
- waste products

26

cations in body fluids include...

- Na
- K
- Ca
- Mg

27

anions in body fluids include...

- Cl
- bicarb
- phosphate
- protein

28

Which 2 ions balance?

Na and Cl

29

fuels in the body fluid include..

- glucose
- lactate
- AA
- ketones

30

proteins in body fluids include...

- albumin
- globulins
- hormones

31

waste products in body fluids include...

- urea
- creatinine
- uric acid
...

32

Na is more abundant in the...

plasma

33

K is more abundant in the...

ICF

34

Ca is more abundant in the...

plasma

35

Cl is more abundant in the...

plasma

36

bicarb is more abundant in the...

plasma (slightly)

37

proteins & phosphates are more abundant in the...

ICF

38

What maintains the neg charge inside cells?

- proteins & phosphates
- cell more permeable to K than Na (RMP closer to K equilibrium potential)

39

proteins & phosphates are not found..

ISF

40

ICF has a ___ charge compared to ECF

neg

41

___ is the same between the ECF and ICF because...

Osmolality
water cross membrane through water channels when there is an osmotic gradient

42

Define: osmolality

particles per volume

43

How is the difference between ICF and ECF generated?

1. Na/K ATPase
2. Neg proteins that can't leave the cell
3. Ion channels

44

The Na/K ATPase pumps...

2 K into cell
3 Na out of cell

45

the RMP is...

-70 mV

46

When ATP is hydrolyzed at the Na/K ATPase, what happens?

Brings 3 Na from inside cell to ECF

47

Why are ionic gradients across cell membrane important?

- nerve conduction
- muscle contraction
- pacemaker activity
- transport in the body
- cell signalling

48

Which ion is responsible for cell signalling?

calcium

49

Example of cell signalling?

secretion of insulin

50

why are ionic gradients important for transport?

water follows Na+, so Na/K ATPase important for building Na+ gradient

51

Mechanism of insulin secretion

1. Glucose starts cell respiration
2. More ATP inside cell
3. High ATP closes K+ channels
4. Inside of cell becomes positive (depolarize)
5. Ca++ channels open, Ca++ comes into cell
6. Ca++ triggers exocytosis of insulin vesicles

52

3 rules of ECF/ICF volume

1. Sodium is always in the ECF
2. WATER is the one that moves across cell membrane
3. Regulate body osmolality by drinking/excreting WATER

53

What hormone is used to make us secrete water?

inhibit ADH (vasopressin)

54

ECF volume depends on...

amount of Na+ in body

55

ICF volume depends on...

ECF Na+ concentration

56

Effect on ICF: hyponatremia

increased volume (big things are hyp(obese))

57

Effect on ICF: hypernatremia

decreased volume (small things are hyper)

58

Relationship between ICF volume and [Na+]

negative

59

Water flux at capillaries is determined by...

Starling forces
1. hydrostatic pressure
2. osmotic pressure

60

There is ___ g/L of albumin in plasma

40

61

Albumin provides...

oncotic pressure

62

Formula: fluid flux

permeability x (hydrostatic pressure gradient - oncotic pressure gradient)

Jv = Kf (hydrostatic - oncotic)

63

Hydrostatic pressure is generated by...

pumping action of the heart

64

___ > ___, and the lymphatic system is used to bring excess ISF back to circulation

filtration
absorption

65

What is net ex-flux?

3L/day

66

causes of edema

1. increased hydrostatic pressure (heart failure)
2. decreased albumin in plasma (liver failure)
3. increased capillary permeability (allergy, trauma)
4. lymphatic obstruction

67

Ways to determine ECF

Plasma volume:
- jugular venous pressure
- BP

ISF volume:
- edema

68

Where is the jugular venous pressure measured?

At external jugular vein

69

What is a cause of distension at the jugular venous pressure?

coronary bypass operation

70

ECF volume can be determined by ___, but ICF can't.

clinical / physical test

71

How is ICF volume determined?

Looking at serum Na+ and osmolality

72

Case: slow marathon runner with headache, nausea, vomit, grand mal seizure, hyponatremia

What did the runner do to cause this?

- Excessive water intake
- Stimulate ADH release (??)