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Flashcards in Body fluid compartments Deck (51)
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1
Q

What molecule assists in moving water between compartments?

A

Aquaporins

2
Q

Through which membrane does glucose move?

A

Endothelium

3
Q

Can electrolytes move through the endothelium?

A

Yes but cell membranes limit transfer

4
Q

Can proteins move through the endothelium?

A

No, they are confined to the endothelium

5
Q

How are proteins moved through the membrane?

A

An active process - membranes engulf the protein to form a vesicle which allows it to be deposited where it is required

6
Q

How do you create a solution?

A

Dissolve solute in solvent

7
Q

From what direction osmolarity will water move?

A

From low to high osmolarity

8
Q

At equilibrium, which two pressures will be equal?

A

Hydrostatic and osmotic

9
Q

How do you determine osmolarity?

A

The number of active particles per unit volume, not their size

10
Q

What is osmolarity?

A

The number of osmoses of a substance in one litre of solution

11
Q

What is osmolality?

A

Number of osmoses per kg of solvent

12
Q

What pressure does 1 mole of glucose exert on a litre of water?

A

10 sm/L

13
Q

When will one mole of a substance exert one osmole of pressure?

A

If the particles remain unchanged in solution and consist of 6.02 x 10^23 particles

14
Q

If a solute dissociates into ions, what happens to the osmotic potential of each?

A

They become osmotically active

15
Q

Which particles generate most of the osmolarity in body fluids?

A

Electrolytes

16
Q

What is tonicity?

A

After the loss of any particles from the administered solution, the remaining osmotic pressure determines the tonicity of the original solution

17
Q

Structure of the phospholipid bilayer

A
Semi-permeable
Studded with proteins, can be full or partial thickness
Hydrophilic heads
Hydrophobic tails
Glycoproteins
18
Q

Another word for hydrophilic

A

Lipophobic

19
Q

Another word for hydrophobic

A

Lipophilic

20
Q

What is active movement?

A

Against concentration gradient

Requires energy

21
Q

What is passive movement?

A

Down concentration gradient

No energy required

22
Q

When will diffusion through a membrane increase?

A

High concentration gradient
Low molecular weight
High lipid solubility
Low degree of ionisation

23
Q

What do aquaporins do?

A

Transmembraneous and allow for water to be transmitted across the lipid bilayer

24
Q

What shape are aquaporins?

A

Narrow and hourglass shaped

25
Q

Are aquaporins charged?

A

Yes

26
Q

What peptide structure is found in aquaporins?

A

Peptide alpha helices

27
Q

What is the main extracellular cation?

A

Sodium

28
Q

What is the main intracellular cation?

A

Potassium

29
Q

Characteristics of sodium/potassium pump

A
3 sodium ions occupy pump
ATP binds to pump and phosphorylates
Causes conformational change
Sodium released into ECF
2 potassium ions occupy pump
Potassium moved to ICF
Phosphate released
ADP and Pi - ATP
30
Q

How is the resting membrane potential achieved by the sodium potassium pump?

A

Selective slow outward leak of potassium

31
Q

What is the main difference between interstitial fluid and plasma?

A

Protein concentration

32
Q

Concentration of sodium in plasma

A

140

33
Q

Concentration of potassium in plasma

A

4

34
Q

Concentration of calcium in plasma

A

2

35
Q

Concentration of magnesium in plasma

A

1.5

36
Q

Concentration of chlorine in plasma

A

100

37
Q

Concentration of HCO3- in plasma

A

25

38
Q

Concentration of HPO4 in plasma

A

2

39
Q

Concentration of proteins in plasma

A

1.2

40
Q

Concentration of glucose in plasma

A

5

41
Q

Concentration of urea in plasma

A

5

42
Q

What is normal plasma osmolarity?

A

280-290 mOsmoles/L

43
Q

What is the name for the pressure created by the protein?

A

Oncotic

44
Q

Where does excess fluid from the capillary get drained to?

A

The lymphatic system

45
Q

How can molecules pass through the capillary endothelium?

A

It has small gaps

46
Q

How can molecules move through the glomerulus?

A

Bigger pores so larger molecules can get through

47
Q

How is movement across the capillary endothelium regulated?

A

Gaps between adjacent cells

Glycocalygeal layers above endothelium

48
Q

Which molecules can fit through the capillary endothelium?

A

Water, electrolytes and small dissolved minerals

49
Q

Which molecules can’t fit through the capillary endothelium?

A

Proteins and cells but this can change as part of the inflammatory response

50
Q

Characteristics of the glycocalyx

A

A gel-like lining
Barrier to fluid loss and WBC migration
Releases nitric oxide to stimulate vasodilation
Profibrinolytic - breaks down clots

51
Q

Which chemical stimulates vasodilation?

A

Nitric oxide