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
What conditions are associated with too much or too little sodium?
Hypernatraemia and hyponatraemia
Which hormones control levels of calcium?
Parathyroid hormone (increases Ca+) and calcitonin (decreases Ca+)
What is the role of the plasma cell membrane?
Maintains homeostasis of the cell by defining cell boundaries, controlling cell interactions and by being selectively permeable.
In the phospholipid bilayer what are the heads and tails in terms of hydrophobic and hydrophilic.
Heads are hydrophilic and tails are hydrophobic
What are the functions of the sodium potassium pump?
Regulating cell volume and maintaining membrane potential.
What is exocytosis?
Things being eliminated or secreted from a cell.
What is the most abundant ion in intracellular fluid?
Potassium
