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104 Cards in this Set
- Front
- Back
What is the normal extracellular concentration of Na? Intracellular?
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145 mM, 15 mM
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What is the normal extracellular concentration of K? Intracellular?
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4.5 mM, 155 mM
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Is the concentration of Cl- higher inside or outside of the cell?
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inside
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Fick's Law
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the rate of diffusion directly depends on the concentration gradient, the surface area of the membrane, and the permeability of the substance, it is inversely related to the molecular weight of the substance, and the thickness of the membrane
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osmotic pressure
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opposing pressure necessary to stop osmosis, increases as the osmolarity increases
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osmolarity
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# osmoles / L solution
= osmoles x concentration |
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effective osmolarity
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takes into account only particles which are impermeable
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cardiac glycosides
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inhibit Na-K-ATPase by preventing dephosphorylation, ex. oubain and digitalis, causes decreased intracellular K+ concentration, increased Na+, and cell swelling
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What is secondary active transport? Co-transport? Counter-transport?
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exploits Na+ concentration gradient created by Na-K-ATPase
co-transport: flows same direction as Na+ counter-transport: flows opposite direction |
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What fraction of total body water is ECF? ICF? What fraction of the ECF is plasma? Interstitial fluid?
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1/3 ECF, 2/3 ICF
1/4 plasma, 3/4 interstitial |
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What is the 60-40-20 rule?
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60% of body weight is water, 40% is intracellular, 20% is extracellular
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total body water
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TBW = 0.7LBM + 0.1AT
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What are the major ions in the intracellular fluid?
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K+>>Na+, PO3-, protein anions, other
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What are the major ions in the extracellular fluid and plasma?
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Na+>>K+, HCO3-, Cl-, other, proteins (plasma)
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plasma osmolarity equation
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plasma osmolarity= 2Na + glucose/18 + BUN/2.8
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Sydrome of Innappropriate Antidiuretic Hormone Secretion (SIADH)
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ADH, normally secreted in response to high plasma osmolarity, is secreted in excess, leading to excess water reabsorption
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Are the following substances hypoosmotic, isotonic, or hyperosmotic to plasma? Diarrhea, sweat, isotonic glucose solution
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diarrhea: isotonic
sweat: hypotonic isotonic glucose: hypoosmotic |
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Aldosterone
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promotes Na+ reabsorption, insufficiency leads to excess secretion of NaCl in urine
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Nerst Equation
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E = (60/Z) log ([ion in]/[ion out])
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What is the equilibrium potential of K+? Na+?
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K+ = -90 mV
Na+ = +65 mV |
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membrane potential equation
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Em= (gkEk +gNaEna)/ (gk + gNa)
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What factors does conductance depend on?
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number of channels, probability that a channel is open, conductance of channel
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Which channels generate graded potentials? Action? Resting?
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graded: ligand, mechanosensitive
action: voltage resting: background |
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What neurotransmitters are excitatory? What sort of channels do they open?
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glutamate, aspartate, mixed-cation (inward Na+ surge, small outward K+)
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What neurotransmitters are inhibitory? What sort of channels do they open?
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glycine, GABA, K+ outward or Cl- inward
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Grand Postsynaptic Potential
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composite of all EPSPs and IPSPs occurring at the same time
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tetrodotoxin and lidocaine
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inhibit voltage-gated Na+ channels, preventing action potentials
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primary hyperkalemic paralysis
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elevated plasma K+ levels causes depolarization of muscles cells, initially spontaneous action potentials occur, then Na+ channels begin to accomodate, unable to fire action potential, resulting in paralysis
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accomodation
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prolonged depolarization of a cell leads to inactivation of Na+ channels. not enough channels available to initiate action potential
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What cells form myelin?
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oligodendrocytes (CNS), Schwann cells (PNS)
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Multiple Sclerosis
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autoimmune disease that results in demyelination
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increase in free calcium
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decreased plasma calcium, acidemia, hyperparathyroidism
reduced neuron excitability |
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decrease in free calcium
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increased plasma calcium, alkalemia, hypoparathyroidism, increased neuron excitability
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Lambert-Eaton Sydrome
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autoimmune disorder in which voltage gated Ca2+ channels are attacked, reduction in ability to reduce neurotransmitters, often associated with certain types of cancer
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tyrosine derivatives
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norepinephrine, epinephrine, dopamine
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in what vessicles are neuropeptides packaged?
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large dense-core vessicles
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Which organs are only innervated by the parasympathetic nervous system?
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sweat glands, peripheral blood vessels, hair follicles, brown adipose tissue, adrenal medulla, kidney
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What neurotransmitter do parasympathetic post-ganglionic neurons release? To what receptors?
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acetylcholine, muscarinic
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What neurotransmitter do sympathetic post-ganglionic neurons release? To what receptors?
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norepinephrine, adrenergic
(exception: release ACh to sweat glands and some skeletal muscle blood vessels) |
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What hormones does the adrenal medulla secrete?
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20% norepinephrine, 80% epinephrine, dopamine (catecholamines)
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Where do parasympathetic cell bodies originate?
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nuclei of brain stem, S2-4
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Where do sympathetic cell bodies originate?
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lateral spinal cord T1-L3
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What receptors receive neurotransmitters from preganglionic neurons? (sympathetic and parasympathetic)
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nicotinic
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choline acetyl transferase
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catalyzes synthesis of ACh from choline and acetylCoA
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acetylcholinesterase
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breaks down ACh in synaptic cleft
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synthesis of norepinephrine
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tyrosine --> DOPA --> dopamine --> norepinephrine --> epinephrine
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How is norepinephrine removed through pre-synaptic cells?
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uptake through uptake-1(inhibited by cocaine and tricyclic antidepressants) and degraded by monoamine oxidase (MAO)
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How is norepinephrine removed through post-synaptic cells?
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uptakes through uptake-2 (not sensitive to cocaine) and degraded by COMT
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Which receptors' signal pathways involve formation of IP3 and DAG and increasing intracellular Ca?
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M1, M3, a1
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Which receptors' signal pathways involve inhibition of adenylate cyclase?
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M2 (+ opening of K+ channels), a2, D2,3,4
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Which receptors' signal pathways involve stimulation of adenylate cyclase?
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B1, B2, D1, D5
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Which receptor's signal pathway involve stimulation of NO?
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B3
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Where are M1 receptors found?
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CNS neurons, some presynaptic sites
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Where are M2 receptors found?
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myocardium, smooth muscle, some presynaptic sites
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Where are M3 receptors found?
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exocrine glands, smooth muscle, endothelium
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Where are a1 receptors found?
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smooth muscle
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Where are a2 receptors found?
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smooth muscle, presynaptic sites, platelets
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Where are B1 receptors found?
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myocardium, adipocytes, juxtaglomerular cells
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Where are B2 receptors found?
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myocardium, smooth muscle
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Where are B3 receptors found?
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myocardium, adipocytes
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Where are D1,5 receptors found?
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brain, smooth muscle of renal vascular bed
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Where are D2,3,4 receptors found?
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brain
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What receptors are found in smooth muscle?
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M2, M3, a1, a2, B2
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What receptors are found in myocardium?
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B1-3, M2
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What receptors are found in presynaptic sites?
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M1, M2, a2
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synaptobrevin
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synaptic vessicle protein
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synaptotagmin
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calcium sensor
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syntaxin and SNAP 25
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plasmalemma associated proteins
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miniature end plate potential
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change in voltage due to the action of one vessicle (quantum=10,000) of ACh
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margin of safety
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difference between threshold and EPP
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tubocurarine (curare)
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competitive antagonist of ACh, prevents muscle movement during surgery
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succinylcholine
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depolarizes the sarcolemma of a muscle fiber, induces short term paralysis, mimics ACh but is degraded more slowly
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botulism toxin
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degrades SNARE proteins, preventing fusion of synaptic vessicles
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anticholinesterase poisoning
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inhibits acetylcholinesterase leading to accumulation of ACh in synaptic cleft, initially muscle fasciculations then paralysis due to receptor desensitization
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Myasthenia Gravis
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circulating antibodies block ACh receptors, decreasing the margin of safety, resulting in some motor units failing to reach threshold
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neostigmine
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reversible acetylcholinesterase inhibitor, prolongs action of ACh, used to treat myasthenia gravis
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What receptor involved in contraction is on the sarcolemma? The sarcoplasmic reticulum?
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DHP, RYR
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store-operated Ca2+ entry (SOCE)
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required to sustain SR Ca2+ stores during repeated contractions
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store-independent Ca2+ entry (excitation-coupled Ca2+ entry [ECCE])
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activated by repetitive or prolonged depolarization
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fascicle
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bundle of muscle fibers
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muscle fiber
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one muscle cell
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myofibril
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bundle of myofilaments
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myofilaments
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actin and myosin
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tropomyosin
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inhibits binding of myosin to actin
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TnC
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calcium sensor, binding of calcium produces conformational change in Tnl
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TnT
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binds troponin complex to tropomyosin, controls position of tropomyosin
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Tnl
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binds to actin and inhibits myosin ATPase
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titan
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stabilizes myosin filaments on longitudinal axis
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nebulin
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regulates length of actin filaments
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I-band
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light, thin filaments only
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A-band
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dark, overlapping thick and thin filaments
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H-band
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light, thick filaments only
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Calsequestrin (CasQ)
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calcium binding protein in SR, helps SR concentrate calcium
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malignant hyperthermia
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due to mutations in genes for RYR or CasQ, calcium channel of SR is abnormally sensitive to anethetics, uncouples calcium release and sarcolemma AP leading to forceful muscle contraction and the generation of heat
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Type 1 fiber characteristics
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"marathon", slow twitch, aerobic, endurance, low power, thinner, high mitochondria
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Type 2 fiber characteristics
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"sprinter", fast twitch, anaerobic, fatigue quickly, high power, thicker, low mitochondria
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mydriasis
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dilated pupil
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miosis
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pupil constriction
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What type of smooth muscle is myogenic? Neurogenic?
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myogenic: single unit
neurogenic: multiunit |
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Which type of smooth muscle cannot fire action potentials?
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multiunit
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What does skeletal muscle contain that smooth muscle does not?
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striations, t-tubules, troponin, sarcomeres
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How can Ca be removed from the cytoplasm of a smooth muscle cell?
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returned to SR by SR-Ca-ATPase
Na/Ca exchanger (antiport) Ca-ATPase |
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cAMP
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inhibits MLCK, decrease muscle tone (ex. albuterol)
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cGMP
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activates myosin phosphatase, decreases muscle tone (ex. nitroglycerine)
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