Cardiac Muscle Properties — Flashcards

Flashcard 1: Which type of muscle fibres undergo hypertrophy ONLY?_____

Answer: Skeletal, Cardiac

Flashcard 2: What type of muscle fibres do not have striations, troponin or T tubules?_____

Answer: Smooth muscle

Flashcard 3: The Ca2+-calmodulin complex upregulates _____, which phosphorylates myosin and contracts smooth muscle.

Answer: myosin-light-chain kinase

Flashcard 4: In muscle contraction, after the muscle cell is depolarized, the action potential travels down the _____ and to the dihydropyridine receptor

Answer: T-tubule

Flashcard 5: Intracellular and extracellular _____ concentrations are the major determinants of the RMP.

Answer: potassium (K+)

Flashcard 6: Sympathetic stimulation (norepinephrine) of a smooth muscle produces _____ potentials and relaxation.

Answer: inhibitory (excitatory/inhibitory)

Flashcard 7: Changes in muscle strength at the onset of muscle contraction due to repeated stimulus known as _____ effect

Answer: staircase

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