Muscle Contraction Chapter 9 Review

Muscle Contraction Vocabulary Match the correct definition to the muscle contraction vocabulary term. Motor neuron Nerve cell used to stimulate muscles to contract Neuromuscular junction Location where a motor neuron and an axon terminal communicate Synaptic cleft Gap found between an axon terminal and motor end plate Synaptic vesicles Sacs found in the axon terminal that store neurotransmitter Axon terminal Enlarged end of a motor neuron that contains synaptic vesicles Muscle Contraction Vocabulary Match the correct definition to the muscle contraction vocabulary term. Synapse Location where two cells communicate Neurotransmitter Chemical used to communicate between 2 cells Motor end plate Highly folded region of the sarcolemma found facing the axon terminal Action potential Nerve impulse used to communicate message along a motor neuron or muscle cell Tropomyosin Protein that covers the myosin binding sites on actin Troponin Protein that binds to calcium causing the uncovering of the myosin binding sites on actin Muscle Contraction Vocabulary Match the correct definition to the muscle contraction vocabulary term. Acetylcholine Neurotransmitter used in muscle contraction Synapse Location where any 2 cells communicate Neuromuscular junction Location where a muscle cell and a motor neuron communicate Neurotransmitter Chemical used to communicate between 2 cells Axon terminal End of the motor neuron that faces the motor end plate and contains synaptic vesicles Steps of Muscle Contraction Place the following steps of muscle contraction under the correct step number. 1 Neuron action potential arrives at end of motor neuron and causes Ca2+ to flow into axon terminal 2 Ca2+ causes synaptic vesicles to release ACh into synaptic cleft 3 ACh diffuses across cleft and binds to ACh receptors on sarcolemma of the muscle cell 4 Opens gated Na+ channels on receptor and Na+ flows across membrane 5 Movement of Na+ across sarcolemma creates muscle action potential 6 Muscle action potential travels along sarcolemma and down T tubules 7 Action potential reaches sarcoplasmic reticulum, which releases Ca2+ 8 Ca2+ binds to troponin on actin filament 9 Binding causes troponin-tropomyosin complex to move away from myosin-binding site on actin 10 Myosin binds to actin forming a cross-bridge 11 Myosin heads “snap” forward and pull actin filaments together, shortening sarcomere 12 The addition of ATP causes myosin heads to release actin. Myosin heads reset, ready to combine with more actin 13 Process will be repeated multiple times shortening muscle fiber = muscle contraction