Action Potential Generation and Propagation — Flashcards

Flashcard 1: In the muscle stretch reflex, stretch increases afferent impulses via _____ and II nerve fibers

Answer: Ia

Flashcard 2: Resting membrane potential of a nerve fiber is equal to the equilibrium potential of _____ and is _____ mV.

Answer: Cl-; -70

Flashcard 3: Resting membrane potential of a _____ muscle is -90 mV

Answer: skeletal and myocardial

Flashcard 4: What kind of muscle fibres have more diameter? (fast or slow twitch)_____

Answer: Fast twitch

Flashcard 5: In muscle contraction, after the muscle cell is depolarized, the action potential travels down the _____ and to the dihydropyridine receptor

Answer: T-tubule

Flashcard 6: When the membrane potential is _____, the inactivation gate of the Na+ channel is closed.

Answer: between +35 mV and the resting potential

Flashcard 7: Sympathetic stimulation (norepinephrine) of a smooth muscle produces _____ potentials and relaxation.

Answer: inhibitory (excitatory/inhibitory)

Flashcard 8: 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.

Flashcard 9: Fast twitch muscle fibers are _____ due to decreased myoglobin concentration

Answer: white

Flashcard 10: _____ is absent in smooth muscle but present in skeletal muscle

Answer: Troponin