Diffusion, body fluid comp, transport Flashcards
What refers to the movement of water down a concentration gradient?
osmosis
What causes osmotic flow?
number of particles (and not particle size) on one side of a permeable membrane
Difference between osmolarity and osmolality?
osmolarity: Osm/L h2o
osmolality: Osm/kg h2o
osmolality will differ due to environmental conditions
What describes the ability of solutions to cause cells to swell or shrink via osmosis?
Tonicity
How do tonicity osmolarity differ?
tonicity describes the ability of a solution to make a cell swell or shrink and osmolarity the movement of water down a concentration gradient
_____ solutions cause cells to swell;
_____ solutions cause cells to shrink
hypotonic; hypertonic
how can cells recover from tonicity?
They retain or dump solutes in the cell to balance
What are the three main fluid compartments?
Intracellular fluid, extracellular fluid, plasma
how much ICF is in the body
28 L
How much ECF is in the body
10.5 L
How much plasma is in the body?
3.5 L
What is the importance of plasma?
Plasma is important because the heart depends on it to generate cardiac output. Small changes in plasma volume can potentially cause large changes in arterial pressure.
Why is the body pH kept within a narrow range?
H ion excess denatures proteins
What are the body’s 3 primary acid defense mechanisms?
Proteins, phosphate, bicarbonate
What is the main acid buffer system in cells (including RBCs)?
proteins
How does a change in plasma pH affect K+ balance?
Plasma pH, if altered, can cause H+ ions to enter the plasma, which would kick out K+ ions to balance it. These potassium ions are dangerous for the heart’s function
What is the main buffer system in the extracellular fluid?
bicarbonate
What is diffusion and how is it affected by concentration, barrier permeability, and surface area?
Diffusion always goes from high to low concentration.
Diffusion increases with increased surface area and permeability
Contrast the differences between pores, channels, and carriers
Pores- always open
Channels- gated
Carriers- binding step
Carriers fastest at low concentrations, slowest at high concentrations
diffusion of molecules across the cell membrane via carrier proteins, channel proteins, or ions (e.g., glucose and fructose transport into cells via GLUT transporters)
facilitated diffusion
The movement of molecules against their concentration gradient across a selectively permeable membrane. Requires ATP as an energy source.
primary active transport
The use of the electrochemical gradient (e.g., generated by primary active transport) of one type of molecule to move another type of molecule against its gradient. Does not directly require ATP. Includes symporters (e.g., the sodium-glucose symporter) and antiporters (e.g., the sodium–hydrogen antiporter).
secondary active transport
Main buffer in ICF
phosphate
main buffer in ECF
bicarbonate
