Muscle Metabolism and Fatigue — Flashcards

Flashcard 1: Slow twitch muscle fibers are _____ due to increased myoglobin concentration

Answer: red

Flashcard 2: Work done in a preloaded muscle contraction is _____ than afterloaded muscle contraction

Answer: more

Flashcard 3: During muscle contraction:- the _____ and I bands, and distance between Z bands, are shortened- the A band remains the same length

Answer: H

Flashcard 4: Fast twitch muscle fibers perform less _____ due to decreased mitochondria

Answer: oxidative phosphorylation

Flashcard 5: What kind of muscle fibres have more diameter? (fast or slow twitch)_____

Answer: Fast twitch

Flashcard 6: After the power stroke in muscle contraction, binding of a new _____ molecule causes detachment of the myosin head from the actin filament

Answer: ATP

Flashcard 7: Intracellular and extracellular _____ concentrations are the major determinants of the RMP.

Answer: potassium (K+)

Flashcard 8: A sustained contraction with little expenditure of energy is made possible by a _____ mechanism in smooth muscle

Answer: latching

Flashcard 9: Soleus has _____ twitch fibres while Gastrocnemius has _____ twitch type fibres

Answer: slow; fast

Flashcard 10: Chemical Events during Muscle Contraction: The **power stroke** is initiated by the release of _____ from the myosin head.

Answer: inorganic phosphate (Pi)

Extra: Sequence of chemical events in the cross-bridge cycle: 1. ATP binding: Myosin head detaches from actin. 2. ATP hydrolysis: Myosin head "cocks" into a high-energy state. 3. Cross-bridge formation: Myosin head binds to actin. 4. Power stroke: Release of inorganic phosphate (Pi) triggers the force-generating pivot. 5. ADP release: Occurs after the power stroke.