Kaap430 exam 1

At the neuromuscular junction, the action potential is transmitted to a muscle fiber by

• Conduction of an electrical impulse down the T tubules

• Release of calcium ions form the sarcoplasmic reticulum

• Binding of acetylcholine to membrane receptors on the sarcolemma

• Sliding of actin and myosin filaments past each other

What is calcium's function during muscle contraction?

• Calcium flows down the T tubules to stimulate the influx of sodium from the sarcoplasmic reticulum

• calcium binds to troponin, changing its shape and removing the blocking action of tropomyosin

• Calcium binds to troponin to prevent myosin from attaching to actin

• Calcium depolarizes the muscle fiber

Type I muscle fibers ______________.

• store large quantities of glycogen.

• Fatigue quickly

• have a high oxidative capacity.

• Generate force quickly

The speed of muscle fiber contraction is determined primarily by the

• Speed of myosin ATPase

• Amount of actin and myosin

• Amount of actin ATPase

• Diameter of the muscle fiber

Why does a sarcomere that is too short or too stretched produce less force?

• The reduction in force is negligible and can be ignored.

• Thin filaments become unraveled

• Not as many cross-bridges can form

• Thick filaments get damaged

What type of protein is found in the thin filaments of muscle fibers and helps to produce muscle contraction according to the sliding filament theory?

• troponin

• actin

• tropomyosin

• myosin

Which is the correct order of events in a contraction?

• T-tubule action potential, cross-bridge cycling, Ca++ released

• T-tubule action potential, Ca++ released, cross-bridge cycling

• Ca++ released, cross-bridge cycling, T-tubule action potential

• cross-bridge cycling, T-tubule action potential, Ca++ released

Type IIa fibers are the most frequently recruited muscle fibers.

• True

• False

The process whereby excess glucose is stored in cells is called

• Glycogenolysis

• Glycolysis

• Gluconeogenesis

• Glycogenesis

Do we have more energy stored in our bodies as carbohydrates or fats?

• Fat

• Carbohydrates

• Equal

• Stored in neither