17 Questions
What is the primary function of the DHP receptor in muscle contraction?
Regulation of Ca2+ release from the sarcoplasmic reticulum
What is the purpose of the tropomyosin and troponin complex in muscle contraction?
To regulate the binding of actin and myosin
What is the source of immediate energy for muscle contractions?
ATP stored in the muscle fiber
What is the effect of Ca2+ binding to troponin?
Enhanced actin-myosin binding
What is the role of the T-tubule in muscle contraction?
Transmission of the muscle action potential
What is the net effect of the muscle contraction process?
Actin filament moves towards the M line
What is the angle of the crossbridge relative to the filaments when 2 ATP binds to its binding site on the myosin?
45°
What is the main mechanism of muscle contraction according to the sliding filament theory?
Thin actin filaments sliding past thick myosin filaments
What happens to the ATP after the ATPase activity of myosin?
It is converted into ADP and Pi
What is the role of tropomyosin in the relaxed state of muscle?
It blocks the binding sites on actin, preventing myosin binding
What is the energy source for muscle contraction?
ATP
What initiates the power stroke in muscle contraction?
The release of Pi from the myosin head
What is the result of the movement of actin filaments in relation to myosin filaments during muscle contraction?
The sarcomere shortens
What is the state of the myosin head at the end of the power stroke?
Tightly bound to the actin molecule
What is the purpose of the myosin head rotating on its hinge during the power stroke?
To push the actin filament past it
What is the role of troponin in muscle contraction?
It binds to calcium ions and pulls tropomyosin away from actin's myosin-binding site
What is the result of the binding of calcium ions to troponin?
Tropomyosin is pulled away from actin's myosin-binding site
Test your knowledge on the Excitation-Contraction Coupling process in muscle physiology, including the role of neurons, motor end plates, and muscle fibers.
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