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Human Physiology Final

Terms in this set (42)

homeostasis
the body's ability to maintain a relatively stable internal environment through a variety of orchestrated physiologic respoonses
what does maintaining homeostasis require?
variable, receptors, integrating center and effectors
what are the three mechanisms to restore homeostasis
1. get rid of excess of substance
2. produce something else that counter balances that excess
3. get rid of part of excess AND add to other side to counter balance
passive movement
movement that occurs without any external energy being required
simple diffusion
unassisted movement of a molecule directly through phospholipid bilayer of plasma membrane
what factors affect flux?
concentration gradient, partition coefficient, diffusion coefficient, thickness of the membrane and surface area
facilitated diffusion
use helper molecule like a channel protein or a carrier protein
what kind of molecules do transmembrane proteins let pass through the membrane?
hydrophobic molecules
binding sites are subject to
affinity, specificity, saturation and competition
specificity of binding site determined by
spatial geometry as well as taking into consideration a range of chemical interactions
lock and key model
substrate and enzyme fit together perfectly
induced fit model
plasticity of binding site
saturation
transport maximum of protein happens when it hits saturatoin
affinity
attractive force a binding site has for a ligand
when does affinity increase
when more ligand is available and being bound
competition of ligands
ligands with similar chemical structure may compete for same binding site
primary active transport
directly utilizes ATP to move against concentration gradient
examples of primary active transport
Na-K pumps and Ca++ pumps
secondary active transport
does not directly utilize ATP, sodium gradient is created to power the transport of a molecule against its gradient
co-transport
substance moves into cell with Na+
counter-transport
substance moves out of cell when Na+ moves in
osmosis
passive movement of H2O across semi-permeable membrane due two different in solute concentration
what is the ultimate hydrophilic molecule that can still move across the cell membrane unrestricted?
water
what are the channels that water moves through called?
aquaporins
what does the van't hoff equation calculate?
osmotic pressure
what two variables affect osmotic pressure?
concentration of solute and reflection coefficient
reflection coefficient
number from 0 to 1, 0 meaning solute penetrates membrane, 1 meaning solute does not penetrate the membrane
osmotic pressure
the pressure necessary to prevent osmosis OR the tendency of a solution to cause osmosis
what separates plasma and interstitial fluid?
capillary endothelium
isotonic fluid has an osmolarity of what
300 mOsm
how does water move in an isotonic solution
no net movement of water
how does water move in a hypotonic solution
water enters the cell and the cell swells
how does water move in a hypertonic solution
water leaves cell and cell shrinks
what three things should we consider when evaluating potential changes in fluid compartments?
identify the change in ECF, how will that change affect osmolarity, and where does water need to move to equilibrate this change?
agonist
a chemical messenger that activates a receptor
antagonist (blocker)
a chemical messenger that binds to a receptor and does NOT activate a receptor
free messenger
part of a messenger that is not bound
what do free messengers do?
diffuse directly across membrane and binds to intracellular receptor
where does the messenger-receptor complex impact the DNA after moving into the nucleus?
hormone response element
how do you keep dynamic equilibrium in blood vessels?
every time a free messenger leaves the blood vessels, a previously bound messenger is released and becomes free
enzyme linked receptors
has a receptor on membrane linked to enzyme on inner part of membrane, kinase or enzyme acts on substrate to phosphorylate it and then brings about a response
channel linked receptor
fast channel/ionotropic channel,
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