Fluids and osmosis Flashcards
What are the fluid compartments within the body?
Intracellular fluid, Interstitial fluid, Extracellular fluid
What is extracellular fluid composed of?
Plasma, Interstitial fluid and Transcellular fluid
What is the composition of the body compartments?
Water freely moves between all compartments. Protein is kept within the intracellular and extracellular compartment. Potassium is kept within the intracellular compartment and Sodium is exchanged between the interstitial fluid and extracellular fluid.
Define osmolarity?
Osmolarity is the concentration of a solution expressed as the total number of solute particles per litre
Is the osmolarity for all the body compartments the same?
Yes
What units do we use for osmolarity?
Osmole per litre. mOsm/L
Define osmolality?
Concentration of a solution expressed as the total number of solute particle per kilogram
What is body fluid osmolality maintained between?
280-295 mOsmol/kg
How does the body monitor water change within it ?
By looking at changes in ECF osmolality.
Describe what happens to cell volume when there is a high presence of inorganic anions within the cell
High inorganic anion presence causes more water to be retained by the cell, lowering water concentration. This leads to increase in water movement within the cell eventually leading to cell lysis.
How can cell lysis be prevented ?
It can be prevented by ion movement and solute expulsion.
When using osmolarity to compare two solutions, what the terms can be used?
Isosmotic, hyperosmotic and hyposmotic
Define Isosmotic?
Solutions containing equal [solute] regardless of permeable or non-permeable solutes
Define hyperosmotic?
Solution osmolarity ([Solute]) of one solution is greater compared to another solution.
Define Hyposmotic?
Solution osmolarity ([solute]) of one solution is lower compared to another solution.
Define tonicity?
The ability of an extracellular solution to make water move into or out of a cell by osmosis
What is tonicity related to?
Tonicity is related to osmolarity.
What are the three terms used to describe tonicity??
Hypertonic. Isotonic and Hypotonic
When can I use the term hypertonic?
When the extracellular fluid has a high osmolarity than the cell. SO water moves out of the cell into the fluid.
When can I use the term Isotonic?
When the extracellular fluid has the same osmolarity as the cell, so there is no net movement of water.
When can I use the term hypotonic?
When the extracellular fluid has a lower osmolarity to the cytoplasm of the cell. So water moves into the cell.
What happens to a cells volume when the cell is places in a hypertonic solution
The cell will lose water to the solution and will shrink in volume.
What happens to a cells volume when placed in a isotonic solution?
Volume remains the same as there is no net movement of water.
What happens to a cells volumes when placed in a hypotonic solution?
The cells volume will increase, so it swells because net H2O movement is into the cell.
How is osmotic balance achieved?
Osmotic balance can be achieved by the extrusion of Na+ this prevents the cell from bursting and uses an active Na+/K+ ATPase pump, giving rise to a voltage difference.
