What structural feature of a skeletal muscle fiber propagates action potentials into the interior of the cell?

Linda's father suffers an apparent heart attack and is rushed to the emergency room of the local hospital. The doctor on call tells her that he has ordered some blood work and that he will be able to tell if her father actually had a heart attack by looking at the blood levels of CK and cardiac troponin. Why would knowing the level of CK and cardiac troponin help to indicate if a person suffered a heart attack?

Describe the events that occur from the time calcium ions enter the axon terminal at the neuromuscular junction until muscle cell contraction occurs.

Multiple ChoiceMore than one choice may apply.After ACh attaches to its receptors at the neuromuscular junction, what is the next step?a. Sodium channels open.b. Calcium binds to regulatory proteins on the thin filaments.c. Cross bridges attach.d. ATP is hydrolyzed.

Chemical A binds and blocks acetylcholine receptors of muscle cells. Chemical B floods the cytoplasm of muscle cells with calcium ions. Which chemical would make the best muscle relaxant, and why?

What forms of energy reserves do resting skeletal muscle fibers contain?

Areas of the body where you would not expect to find slow fibers include the (a) back and calf muscles, (b) eye and hand, (c) chest and abdomen, (d) all of these.

For each portion of a myogram tracing a twitch in a stimulated calf muscle fiber, describe the events that occur within the muscle fiber.

Characteristics of isometric contractions include all buta. shortening,b. increased muscle tension throughout the contraction phase,c. absence of shortening,d. used in resistance training.