Term
| Integral proteins vs. Peripheral Proteins |
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Definition
| Peripheral proteins are not embedded in the membrane nor are they covalently attached. Held by electrostatic interactions. |
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Term
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Definition
J = -PA (C1-C2)
J = flux (mmol/sec); P = permeability (cm/sec); A = area; C1,C2 = concentration |
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Term
| Carrier-mediated transport exhibits three characteristics: |
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Definition
| Stereospecificity, saturation, competition |
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Term
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Definition
O = g x C
O = concentration (osm/L)
g = number of particles
C = concentration |
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Term
| Osmotic Pressure equation |
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Definition
pi = g x C x RT
pi = osmotic pressure (mmHg or atm) |
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Term
| Reflection coefficient, sigma |
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Definition
| Describes permeability of a solute. 1 = impermeable, 0 = permeable. Multiply by osmotic pressure to get effectice osmotic pressure |
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Term
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Definition
| Potential difference generated across a membrane by a concentration difference of an ion. |
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Term
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Definition
| Diffusion potential at which no more net ion movement happens. |
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Term
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Definition
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Term
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Definition
| Depol = opening of Na activation gates, slow closing of Na inactivation gates and slow opening of K channels. Repol = high K conductance returns cell to resting potential w/ undershoot. |
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Term
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Definition
| Absolute = no AP can occur; Relative = requires a larger than usual stimulus to elicit an AP. Also see Effective |
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Term
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Definition
| Membrane potential is held at a depolarized level higher than threshold without APs because Na inactivation gates are closed. Happens in hyperkalemia when high serum K depolarizes cells. |
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Term
| Events at neuromuscular junction |
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Definition
| Choline acetyltransferase makes ACh from acetyl-CoA and choline. AP opens Ca channels at presynaptic terminal. Ca causes ACh to be released, which binds nicotinic receptors. Receptor is both an Na and K channel, so membrane is depol. to 0mV (mini EPP). Summation of MEPP is an EPP. Acetylcholineesterase degrades ACh. |
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Term
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Definition
| Antibodies to ACh receptor cause skeletal muscle weakness. Treat with AChE inhibitors. |
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Term
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Definition
| EPSPs are caused by opening of Na and K channels bringing potential to 0mV, ACh, norepi, epi, dopa, glu, serotonin. IPSPs open Cl channels bringing potential to -90mV, GABA and gly. |
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Term
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Definition
| Spatial occurs when two inputs arrive simultaneously. Temporal occurs when two inputs arrive in rapid succession. Both produce greater depol. |
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Term
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Definition
| Released from post. sym. neurons. Removed by reuptake or metabolized by MAO and COMT. Pheochromocytoma, tumor or adrenal that produces catecholamines is detected by increased urinary VMA, a metabolite. |
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Term
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Definition
| Synthesized from norepi by phenylethanolamine-N-methyltransferase. |
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Term
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Definition
| Prominent in midbrain neurons, inhibits prolactin release. Metabolized by MAO and COMT. D1 receptors are Gs protein, D2 receptors are Gi. Parkinson's is degeneration of neurons with D2 receptors; Schizo is increased levels of D2 receptors. |
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Term
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Definition
| In high concentrations in brain stem. Made from trp, converted to melatonin in pineal gland. |
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Term
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Definition
| Most prevalent excitatory transmitter in brain. Has four subtypes of receptor, three are ionotropic including the NMDA receptor, one is metabotropic. |
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Term
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Definition
| Inihibtory, synthesized from glutamate by glutamate decarboxylase. GABAa receptor increases Cl conductance, is hit by benzos and barbiturates, GABAb receptor increases K conductance. |
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Term
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Definition
| Short acting inhibitory transmitter, made by NO synthase. |
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Term
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Definition
| Invaginations of plasma membrane in skeletal muscle. Contains dihydropyridine receptor in the membrane, important for initiating excitation-contraction coupling. |
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Term
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Definition
| Myosin, composed of two heads and a tail, which include one pair of heavy chains and two pairs of light chains. The heads bind ATP and actin to form cross-bridges. |
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Term
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Definition
| Actin, troponin and tropomyosin. |
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Term
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Definition
| Z line to Z line, where thin filaments attach. M line at middle of thick filaments. I band has only thin filaments, A band has thick filaments (w/ or w/o thin), and H band has no thick filament heads. |
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Term
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Definition
| Three proteins: Troponin I inhibits the interaction of actin and myosin, C binds calcium and T that attaches to tropomyosin. |
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Term
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Definition
| In skeletal muscle, a voltage sensor that changes conformation with depolarization, opening the ryanodine receptor, releasing calcium. |
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Term
| Excitation-contraction coupling (skeletal muscle) |
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Definition
| DhP receptor senses depolarization, opens ryanodine receptor, Ca flows out of SR and binds troponin. Myosin hydrolyzes bound ATP and displaces toward plus end of actin, then binds actin and "power strokes" back to position and releases ADP. When Ca is taken up by the SR, troponin moves tropomyosin back into place to block actin-myosin interaction. |
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Term
| Multi-unit vs. unitary smooth muscle |
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Definition
| Multi-unit smooth muscle is not coupled and behaves as separate units, such as iris, ciliary muscle of the eye and vas deferens. Unitary smooth muscle is spontaneously active, is electrically coupled and is the most common type, in the uterus, GI tract and ureter. |
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Term
| Excitation-contraction coupling (smooth muscle) |
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Definition
| No troponin. Ca is let in from outside the cell (from voltage or ligand-gated channels, which can bind hormones and neurotransmitters). Ca then binds calmodulin which binds to and activates myosin light chain kinase. Phosphorylated myosin can bind to actin and start cross-bridge cycling. |
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