What is the primary cause of 'Rigor Mortis' after death?
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Correct answer: Absence of ATP, which is required for myosin heads to detach from actin
ATP binding is necessary to break the cross-bridge between myosin and actin. When ATP production ceases after death, the myosin heads remain 'locked' to the actin, causing permanent muscle stiffness until tissue decay begins.
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More Muscle Physiology: Contraction Mechanisms questions
- Which enzyme is responsible for the hydrolysis of the neurotransmitter at the neuromuscular junction to allow muscle relaxation?
- During muscle contraction, the sarcoplasmic reticulum (SR) releases calcium through which specific channels?
- The resting membrane potential of a skeletal muscle fiber is primarily maintained by the unequal distribution of which ions?
- What is the function of the protein 'Titin' in the sarcomere?
- Which of the following is the 'rate-limiting step' for muscle relaxation?
- In the cross-bridge cycle, what must happen before the myosin head can return to its 'high-energy' (cocked) position?