Fluid Compartments

Question 1

Main Fluid Compartments of 70Kg man

Answer 1

Intracellular = 23L (55%)
Extracellular = 19L (45%)
Interstitial = 15L (36%)
Blood Plasma = 3L (7%)
Transcellular e.g. CSF, ocular = 1L = 2%

Question 2

Osmolarity Definition

Answer 2

Concentration of a solution expressed as the total number of solute particles per litre

Question 3

Tonicity Definition

Answer 3

The ‘strength’ of a solution as it affects final cell volume. This depends on cell membrane permeability as well as solution coposition.

Question 4

Types of solution

Answer 4

Hypertonic = cell shrinks
Hypotonic = cell swells
Isotonic = cell is unchanged

Question 5

Things transported across membranes?

Answer 5

• hydrophobic molecules
• small uncharged polar molecule
• large uncharged polar molecules
• ions

Question 6

Methods of transport across membrane

Answer 6

1) Passive - Down electrochemical gradient e.g. through lipid, pores or on carriers
2) Active - Against electrochemical gradietn e.g. on carriers primary, on carriers secondary via coupling
3) endo/exocytosis

Question 7

Colloid Osmotic Pressure Definition

Answer 7

Osmotic pressure due to the plasma proteins. This draws water in

Question 8

Hydrostatic pressure definition

Answer 8

Pressure in a circulatory system exerted gy the volume of blood when it is confined in a blood vessel. this pushes water out.

Question 9

Oedema Definition

Answer 9

Swelling of a tissue because of excess interstitial fluid. This is one of the cardinal signs of infection.

Question 10

Oedema Causes

Answer 10

• Imbalance of forces ccausing fluid to move between plasma, interstitium and Lymphatic vessels