Resting Membrane Potential — Flashcards

Flashcard 1: What change is seen in the RMP when the extracellular concentration of Na+ increases ?_____

Answer: No change

Flashcard 2: When the membrane potential is _____ mv the activation and inactivation gate of Na+ channel is open

Answer: between -90 to +35

Flashcard 3: For K+ ion the equilibrium potential calculated by Nernst equation is _____.

Answer: -90mV

Flashcard 4: Intracellular and extracellular _____ concentrations are the major determinants of the RMP.

Answer: potassium (K+)

Flashcard 5: 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 6: _____ enters smooth muscle cells via L-type Ca2+ channels and binds to calmodulin, leading to smooth muscle contraction.

Answer: Ca2+

Flashcard 7: Fast twitch muscle fibers are _____ due to decreased myoglobin concentration

Answer: white

Flashcard 8: _____ is absent in smooth muscle but present in skeletal muscle

Answer: Troponin

Flashcard 9: During muscle contraction:- the _____ and I bands, and distance between Z bands, are shortened- the A band remains the same length

Answer: H

Flashcard 10: After the power stroke in muscle contraction, binding of a new _____ molecule causes detachment of the myosin head from the actin filament

Answer: ATP