Fluid compartments

Question 1

What are the main fluid compartments?

Answer 1

Intracellular fluid
Extracellular fluid
- Blood plasma
- Interstitial fluid
- Transcellular fluid

Question 2

What composes intracellular fluid?

Answer 2

High K+ and organic phosphate concentration
Low H+ concentration
Low -ve protein concentration BUT high charge

Question 3

What composes extracellular fluid?

Answer 3

High Na+ and Cl- concentration

Low H+ concentration

Question 4

How is the extracellular environment compartmentalised?

Answer 4

Endothelial cells lining blood vessels
Epithelial cell layers
Plasma membrane

Question 5

What percentage body water is contained in the intracellular fluid?

Answer 5

55%

Question 6

What percentage body water is contained in the compartments within the extracellular fluid?

Answer 6

7% Blood plasma
36% Interstitial fluid
2% Transcellular fluid
(total 45% extracellular fluid)

Question 7

Define osmosis

Answer 7

Passive movement of water to an area of higher osmolarity

Can change cell volume

Question 8

Define diffusion

Answer 8

Passive spontaneous movement of molecules down an electrochemical gradient
via lipid pores or carrier proteins

Question 9

What are two crucial factors in osmosis?

Answer 9

Membrane permeability of solutes

Osmolarity

Question 10

Define osmolarity

Answer 10

Measure of conc of all solute particles in a solution

Question 11

What are the main mechanisms of solute exchange across cell membranes?

Answer 11

Passive:
-Diffusion
-Osmosis
Active:
-Active transport
-Co-transport
-Endo/exocytosis

Question 12

Explain the permeability of the lipid bilayer

Answer 12

Permeable to:
-Small hydrophobic molecules
-H2O
Impermeable to:
-Some small uncharged polar molecules
-Large uncharged polar molecules
-Ions

Question 13

What is the difference between tonicity and osmolarity?

Answer 13

Tonicity accounts for cell membrane permeability as well as solution composition
Osmolarity only accounts for solution composition

Question 14

How may tonicity impact on the integrity of cells?

Answer 14

Large transient changes to cell volume can result in cell damage

Question 15

Define oedema

Answer 15

Tissue swelling due to XS interstitial fluid, more that can be collected and returned by the lymphatic system

Question 16

What causes oedema?

Answer 16

Imbalance in the normal cycle of fluid exchange
Inflammation
Compromised lymphatics system
Increased hydrostatic pressure in vessels

Question 17

What are the main types of exchange across the capillary wall?

Answer 17

Small water soluble pass through water filled pores between cells
Lipid soluble pass through endothelial cells
Exchangeable proteins moved in vesicles
Plasma proteins cannot move