141967
Description
Flashcards by dancedrill, updated more than 1 year ago
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Created by dancedrill
over 11 years ago
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| Question | Answer |
| When a skeletal muscle contracts to cause a given movement, the relatively stationary end of attachment of the muscle is termed? | Origin |
| This statement best describes the muscle property of "extensibility? a. muscles recoil to original shape b. muscles shorten forcefully c. muscles can stretch when needed d. muscles contract when stimulated | c. muscles can stretch when needed. |
| These statements about creatine phosphate are true except: a. accumulates in cells to store energy b. ADP reacts with it to produce ATP c. creatine kinase is used as a catalyst d. supports intense exercise for up to 3 minutes. | d. supports intense exercise for up to 3 minutes. |
| These statements about myosin myofilaments are all true except:? a. are thicker than actin. b. make up the H zone. c. attached to the Z disc d. attached to filaments that form the M line. | c. attached to the Z disc |
| The resting membrane potential occurs when:? a. Na+ ions diffuse into the cell b. Na+ ions diffuse out of the cell. c. K+ ions diffuse into the cell. d. K+ ions diffuse out of the cell. | d. K+ ions diffuse out of the cell. |
| These events occur during contraction except:? a. exposure of active sites on actin. b. active transport of Ca+ back into sarcoplasmic reticulum c. cross-bridges are formed and released. d. power stroke. | b. active transport of Ca+ back into sarcoplasmic reticulum. |
| Depolarization must reach this value in a cell to trigger an action potential: a. 0 mv b. +20 mv c. -85 mv d. threshold | d. threshold |
| This stimulus results in the greatest force of contraction because all motor units of a muscle are responding: a. threshold b. subthreshold c. maximal d. supramaximal | c. maximal. |
| List the events occurring at a neuromuscular junction in order. 1. ACh binds to receptors on postsynaptic membrane. 2 acetylcholinestrerase breaks down ACh 3. choline is reabsorbed by presynaptic membrane 4. depolarization of sarcolemma 5. ligand gated Na+ ion channels open a. 1,5,4,2,3 b. 5,3,2,1,4 c. 1,4,2,3,5 d. 1,5,2,3,4, | a. 1,5,4,2,3 |
| This kind of contraction results in an increase of tension, but the length of the muscle does not change: a. isometric b. isotonic c. concentric d. eccentric | a. isometric |
| These conditions occur in both physiologic contracture and rigor mortis except: a. low levels of ATP b. cross-bridges are formed c. release of cross-bridges d. Ca2+ builds up in the sarcoplasm 3. active transport of Ca2+ slows or stops. | c. release of cross-bridges. |
| Given the following: 1. Ca2+ ions are actively transported back into sarcoplasmic reticulum 2. Troponin-tropomyosin complexed move to inhibit cross-bridge formation 3. muscle fibers lengthen passively These events best describe? a. treppe b. lag phase c. contraction phase d. relaxation phase | d. relaxation phase. |
| Johnny's primary source of energy comes from this as he runs on his treadmill for 20 minutes every morning?: a. stored ATP b. aerobic respiration c. anaerobic respiration d. creatine phosphate. | b. aerobic respiration |
| This statement is true about anaerobic respiration: a. produces 38 ATPs per glucose molecule b. uses fatty acids for sustained exercises. c. can produce ATP rapidly d. uses citric acid cycle. | c. can produce ATP rapidly. |
| These are the most important neurotransmitters that regulate smooth muscle: a. acetylcholine, dopamine b. norepinephrine, dopamine c. acetylcholine, norepinephrine, d. GABA, Ach | c. acetylcholine, norepinephrine. |
| Because large amounts of ATP are stored in muscle fibers, it does not need to be continuously synthesized in order to sustain muscle contraction a. true b. false. | b. false. |
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