Lecture 3 Flashcards
body fluid compartments
ICF and ECF
ICF
2/3 of total body water volume
ECF
1/3 of total and consists of interstitial fluid and blood plasma
interstitial fluid
lies between circulatory system and cells
blood plasma
liquid matrix of blood
ECF and ICF are in…
osmotic equilibrium
osmosis
movement of water across a membrane in response to a solute conc. gradient
water can move freely between…
ICF and ECF through aquaporin channels
how many different aquaporin channels?
13
osmotic equilibrium does not equal…
chemical or electrical equilibrium
osmolarity
describes the number of particles in solution (osmol/L)
osmotic movement of water can be predicted by knowing…
the concentrations of each solution
normal osmolarity in the human body is….
280-296 mOsm
isosmotic
solutions have identical osmolarities
hypersmotic
describes the solution with the higher osmolarity
hyposmotic
describes the solution with the lower osmolarity
tonicity
describes a solution and how it would affect cell volume if a cell were placed in the solution and allowed to come to equilibrium
water moves in higher penetrating or non-penetrating?
non-penetrating
simple diffusion
the movement of molecules from an area of high conc. to low conc.
Diffusion uses…. energy and not…..
kinetic, outside energy
diffusion continues until….
conc. come to equil.
diffusion is faster…
- along higher conc. gradients
- over short distances
- at higher temp.
- for smaller molecules
rate of diffusion through a membrane is faster if…
- larger membrane surface area
- thin membrane
- large conc. gradient
- membrane is more permeable to molecule
membrane permeability depends on…
- molecule’s lipid solubility
- molecule size
- lipid composition
Law of Diffusion
Fick
channel proteins
made of membrane spanning protein subunits with a pore through the center; FAST
how are channel proteins names?
according to substances that pass through
open channels =
leak channels
different kinds of gated channels
chemically, voltage, and mechanically
carrier proteins
large complex proteins that slowly transport substance that cannot pass through channels by changing conformation
