Fluid Homeostasis and NFP Flashcards
List the distribution of body fluids.
- Intracelluar fluid (ICF) within cells
- Extracellular fluid (ECF) outside cells
- interstitial
- intravascular
The extracellular compartment actually has two components. Can you name them?
- Interstitial compartment (between cells but outside blood)
- Vascular compartment (plasma, CSF, lymph, urine, etc).
Where is the water physically moving through?
Aquaporins of the plasma membrane
Osmolality
A measure of the number of solute in a solution
Define osmoles.
Number of solute in a solution (after association of molecule)
What is the normal osmolality of plasma?
285-295 mOsm (osmolality in milliosmole)
True or False:
The intracellular fluid and interstitial fluid have the same osmolality or solute concentration (normally)
True! We call this isotonic, which is vital for our survival.
Between the extra cellular compartments, what type of movement do we see?
Filtration
Between the intracellular compartment and the interstitial compartment, what type of movement do we see
Osmosis
What molecules do we mainly find inside the cell (intracellular)?
Main cation is K+
Main anions are phosphates and proteins
Molecules do we mainly find outside of the cell, in the interstitial fluid?
Main cation is Na+
Main anion is Cl-
True or False:
Concentration level of molecules is the different between intracellular and interstitial.
False
Total concentration is at the same level between the two. However, molecules vary in their specific concentrations.
What is the big rule of osmosis?
Water follows solute
Why is the cell membrane selectively permeable to electrolytes but not to water?
Electrolytes or ions are charged
How can we track the strength of a solution?
By looking at its osmolality (solute concentration)
If a solution has a higher osmolality, what can we conclude?
We can conclude that the solution has more solutes in it. This means there is a greater tendency for water to move towards or into the high solute solution.
List the types of solution strengths relative to a cell.
Hypertonic
Hypotonic
Isotonic
Hypertonic solution
Solution has more solutes than inside the cell
Water moves out of the cell by osmosis, causing cell to shrink
Crenation
Shriveling of a cell
Hypotonic solution
Solution has fewer solutes than inside the cell
Water moves into the cell by osmosis and the cell will swell
Hemolysis
When a blood cell ruptures from too much water
Isotonic solution
Solution has the same solute concentration as inside the cell
Is there any net movement of water in an isotonic solution?
No
Which of the three solution strengths are the normal homeostatic condition?
Isotonic
Say I have a cell with 300 mOsm that is in a solution of 500 mOsm. What’s going to happen to the cell?
Cell will shrink and undergo crenation
Say I have a cell with 300 mOsm that is in a solution of 100 mOsm. What’s going to happen to the cell?
Cell will lyse
What is osmotic pressure?
The pressure required to PREVENT the movement of water by osmosis across a cell membrane.
What creates osmotic pressure?
The number of solutes in a solution.
If a cell contains high solute and is in a low-solute environment, then there will be increased osmotic pressure INSIDE the cell because that solute is causing a huge influx of water, creating more tension as water flows into the cell.
