PHYSIOLOGY
MUSCLE CONTRACTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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rest, nerve action, ACh released, transmitted, Ca released
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ACh released, Ca released, nerve action, transmitted, rest
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rest, nerve action, Ca released, ACh released, transmitted
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ACh released, Ca released, transmitted, nerve action, rest
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Detailed explanation-1: -(A) Binding of myosin head to exposed active site of actin forming the cross-bridge by utilising the energy from hydrolysis of ATP. (B) Binding of Ca++ with troponin of actin filaments and thereby removing the masking of active sites for myosin.
Detailed explanation-2: -Depolarisation and calcium ion release. Actin and myosin cross-bridge formation. Sliding mechanism of actin and myosin filaments. Sarcomere shortening (muscle contraction)
Detailed explanation-3: -Acetylcholine release. Acetylcholine’s action. Increasing endplate potential. Potential for a miniature endplate development. Acetylcholine is destroyed.
Detailed explanation-4: -Action potential travels down motor neuron. Acetylcholine (ACH) released into sarcolemma. Action potential on sarcolemma. Sodium ions (Na+) rush into muscle cell. Calcium (Ca+) released from cisternae. Myosin heads attach to actin. Muscle contracts.