Water Balance Flashcards
A deficit in body fluids is caused by what?
Vomiting, diarrhoea, excessive sweating, low water intake, drainage from burns and damage to thirst mechanism.
Why do we need water?
It’s a universal solvent, chemical reactions occur in water, major component of plasma and cells, lubricant of joints and organs.
What is contained in an aqueous solution?
Small molecules dissolved and ionic compounds dissociate (anions – and cations +)
What is contained in a colloid solution?
Proteins or other large molecules as solutes
What is contained in suspensions?
Larger molecules than colloid solutions. The particles will settle if undisturbed.
What is osmolality?
The number of osmoles per kg of water
What is osmolarity?
The number of osmoles per L of water
What is iso osmotic
Where the concentration of electrolytes outside the cell is equal to that inside the cell.
What is a hypotonic solution? What would happen to a cell in a hypotonic solution?
A solution that has low concentration of solutes, is very dilute. Cells in a hypotonic solution would absorb the water and swell.
What is a hypertonic solution? What would happen to a cell in a hypertonic solution?
A solution that has a high concentration of solutes. Cells in a hypertonic solution would shrivel as water moves out of the cell.
Where is the thirst centre located in the brain?
The hypothalamus
What role does ADH play in water balance?
Retains water in the kidneys (stops peeing)
Treatments for dehydration?
Fluid therapy, gelofusine, 0.9% saline and 5% glucose solution.
Which extracellular ion is the most dominant?
Sodium (Na+)
Which hormones control levels of sodium?
ANP and aldosterone
