Body fluids

Question 1

What is intracellular fluid

Answer 1

• The fluid within cells
• known as cytoplasm
• It is about 28 litres in a 70 kg person

Question 2

what is extracellular fluid

Answer 2

• All fluids found outside the cells.
• This is about 14 litres in a 70 kg person.

Question 3

what is transcellular fluid

Answer 3

• Fluid in the CSF,
• joints,
• ocular fluid,
• G-I tract, about 0.8 litres

Question 4

what is interstitial fluid

Answer 4

• Fluid between the cells of tissues,
• including lymph.
• about 10.2 litres

Question 5

what are the 4 processes that affect the total volume of each type of body fluid

Answer 5

1. Filtration
2. Reabsorption
3. Diffusion
4. Osmosis

Question 6

what is osmosis

Answer 6

The movement of water molecules from a low solute concentration (dilute) to a high solute concentration (concentrated) across a semi-permeable membrane.

Question 7

what is osmotic pressure

Answer 7

the pressure that must be applied to oppose osmosis

Question 8

what is osmolarity and how to calculate it

Answer 8

• it is the total number of dissolved particles (ions, molecules or mix of both) per litre of solution.
• Molarity x number of particles per molecule once the particle dissolves
• for an undissociated molecule (e.g. glucose) 1 mole = 1 osmole
  For a solute that fully dissociates (e.g. NaCl) 1 mole = 2 osmoles
  for a protein (e.g. albumin) 1 mole = 1 osmole
  Measured in osmoles/ litre of solution (osmol/L or OsM)

Question 9

what is osmolality

Answer 9

• The total number of dissolved particles (ions, molecules or mix of both) per Kg of water.
• (osmol/kg or OsM)

Question 10

what is a hypotonic solution

Answer 10

a solution that causes cellular swelling.

Question 11

what is a hypertonic solution

Answer 11

a solution that causes cellular shrinkage