Lecture 1 Flashcards
What is the difference between interstitial and plasma fluid in the ecf?
Plasma is inside blood vessels and is smaller of two. and interstitial fluid is an ultra filtrate of plasma
What is the percentage of icf and ecf?
Icf is 2/3 tbw and ecf is 1/3 of tbw
What is osmolar it’s
Concentration of particles in solution. If it does not dissociate, like glucose,then osmolarity is equal to molar it’s. If it dissociates you have to multiply it by the number of moles.
What is the composition of na in ecf and icf
140 mEq/L in ecf, 14mEq/L in ICF
What is the composition of k in icf and ecf
4 in ecf, 120 in icf
How is osmolarity maintained
Water flows freely through compartments
How does na-k ATPase work
Transports na out of cell (icf to ecf) and k into cell (ecf to icf). Against electrochemical gradient, so ATP is required
How does ca ATPase work
Pumps ca against electrochemical gradient by outdoing ca out of cell to keep intracellular levels low
Resting membrane potential depends on what
The concentration difference between K
The upstroke of the action potential depends on what
Na concentration difference
Excitation-contraction coupling depends on which ion
Ca across membrane and sarcoplasmic reticulum
Absorption depends on what
Na across membrane
Gibbs-Donovan equation
Gives concentrations of plasma relative to interstitial fluid. Describes distribution of permeant ions- proteins are in plasma and have a negative charge so there are less anions in plasma.
What is the reflection coefficient
Dimensionless number between 0 and 1 that describes how easily solute crosses the membrane
What does a reflection coefficient of 1 mean?
Membrane is impermeable, solute retained in original solution, and exerts full osmotic force
