PHYSIOLOGY
SKELETAL MUSCLE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Trinity is trying with all his might to pull a tree stump out of the ground. It does not budge. Which type of contraction are his muscles undergoing?
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simple contractions
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Isotonic contractions
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Isometric contractions
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no contractions taking place
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Explanation:
Detailed explanation-1: -Skeletal muscle contraction begins first at the neuromuscular junction, which is the synapse between a motoneuron and a muscle fiber. Propagation of action potentials to the motoneuron and subsequent depolarization results in the opening of voltage-gated calcium (Ca2+) channels of the presynaptic membrane.
Detailed explanation-2: -A sarcomere is the basic contractile unit of a myocyte (muscle fibre). A sarcomere is composed of two main protein filaments (thin actin and thick myosin filaments) which are the active structures responsible for muscular contraction.
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