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Muscle Phys
USCSOM: Physiology Muscle
| Question | Answer |
|---|---|
| Thick filaments are polymers of ______ | myosin |
| Thin filaments are polymers of _______ | actin |
| What blocks the myosin binding site on actin? | tropomyosin |
| What type of troponin binds tropomyosin? | Troponin T |
| What type of troponin inhibits actin/myosin interaction? | Troponin I |
| What type of troponin binds calcium to unblock the myosin binding site? | Troponin C |
| What enzyme transports Ca into the Sarcoplasmic reticulum? | SERCA (Sarcoplasmic endoplasmic reticulum Atp ase) |
| What is EPP? | End Plate Potential |
| What is the equilibrium potential for K? | -90 mV |
| What is the equilibrium potential for Na? | +69 mV |
| What is the equilibrium potential for ACh? | -20 mV |
| What two membrane enzymes are involved with Calcium release in the SR? | ryanodine receptor and DHP (dihydropyridine) receptor |
| What kind of receptors are at the neuro-muscular junction? | nicotinic acetylcholine receptors |
| What disease involves activation of ryanodine receptors by anesthetics? | malignant hyperthermia |
| What is the response to a single action potential? | twitch response |
| What is the term for the maximum response for a muscle fiber? | tetanus |
| What is the term for the force developed for no change in length? | isometric contraction |
| What is the term for a muscle contraction with a constant load? | isotonic contraction |
| What type of muscle fibers are Type I? | slow twitch, slow oxidative |
| What type of mm fibers are Type IIb? | fast, fatigable |
| What type of mm fibers are Type IIa? | fast, fatigue resistant |
| What are dense bodies? | attachment points of actin filaments in smooth muscle |
| What are caveoli? | membrane invaginations of smooth muscle |
| In smooth muscle, Ca binds to what enzyme? | calmodulin |
| Activated calmodulin activates what phosphorylating protein? | MLCK (myosin light chain kinase) |
| What level of phosphorylation is required to produce maximum force? | 30-40% |