| Term | Definition |
|---|
| Extracellular Matrix | meshwork of collagen & elastin fibers |
| Integrins | glycoprotein adhesion molecules that hold cells to to extracellular matrix |
| What percent of water is found within cells? | 67% |
| What percent of water is found in interstitial fluid? | 80% |
| What percent of water is found in blood plasma? | 20% |
| What type of compounds readily diffuse thru cell membrane? | Non-polar & small polar |
| ion channels | transporters that move charged molecules across the plasma membrane |
| Rate of diffusion factors... | 1. magnitude of CG, 2. permeability of membrane to solute, 3. temperature, 4. surface area of membrane |
| Osmotically active | solutes that cannot readily move across the membrane, cause osmosis to occur toward them (the solutes) |
| Aquaporins | water channels in membrane that aid in osmosis |
| Osmotic Pressure | The force necesary to stop osmosis (how strongly H2O wants to diffuse) |
| Molality | 1 mole of solute (all solutes) dissolved in 1kg H20 |
| Osmolality (Osm) | total molality of solution |
| Isosmotic | solutions have same osmolality as plasma |
| Hypo-osmotic | lower osmotic pressure than plasma |
| Hyperosmotic | higher osmotic pressure than plasma |
| Standard Blood Osmolality | roughly 300mOsm |
| Osmoreceptors | found in hypothalamus, stimulated by dehydration, causes release of ADH (conserve H20 & thirst) |
| Saturation | all carriers occupied (Tm = transport max) |
| Facilitated Diffusion | passive transport down conc. gradient by carrier proteins |
| Na+/K+ pump | active trans. moves 3Na+ out, 2K+ in against gradients |
| Secondary Active Transport | 1. ATP used to move ion against conc. gradient 2. energy from first step to move another molecule with CG |
| Cotransport | Symport; secondary transport in same direction as Na+ |
| Countertransport | Antiport; moves molecule in opposite direction to Na+ |
| Absorption | transport of digestion products across intestinal epithelium into blood |
| Reabsorption | movement of compounds in urinary filtrate back into blood |
| Transcellular transport | moves material from 1 cell to another |
| Paracellular transport | material through gaps in between cells (ex: simple squam.) |
| Junctional Complexes | 1. Tight junctions (zipper) 2. Adherens (glue between cytoskeletons) 3. Desmosomes (button) |
| Bulk Transport | Movement of large molecules and particles across plasma membrane |
| Membrane Potential | difference in charge across membranes (large anions trapped inside cell); K+ attracted into cell by anions; Na+ not permeable (too large) and is actively transported out |
| Equilibrium Potential | (Ek) voltage across cell membrane if only 1 ion could diffuse |
| Nernst Equation (Ex) | membrane voltage needed to counteract conc. forces acting on an ion |
| Resting Membrane Potential (RMP) | membrane voltage of cells not producing impulses (-65 to -85 mV); affected most by K+ (is most permeable) |
| What do nonpolar regulatory molecules affect... | Transcription (ex: steroid & thyroid hormones & NO2 for vasodialation) |
| Polar regulatory molecules must... | bind to surface receptors to send 2nd messengers to mediate actions of regulatory molecule (ex: Ca+, G-protein, & cyclic AMP) |
| G-protein | 1. 2nd messengers; 2. contains 3 subunits (alpha, beta, gamma) that dissociate when cell surface receptor is activated; 3. subunit binds to ion channel or enzyme which changes their activity |
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