Unit 2 Challenge 2

Which of these are the proteins that make up muscle fibers?

Actin and myosin

Which of the following statements about muscle building is associated strength training?

Lifting weights regularly increases muscle size.

Which of these describes atrophy?

Muscle tissue shrinks

What are long chains of myofilaments called?

Myofibrils

Which of the following represents a voluntary muscle contraction?

Robert kicks a soccer ball into the goal.

Which of the following statements is true? a.)The muscles in your hand that allow you to write are examples of red skeletal muscles. b.)Red skeletal muscles are the most efficient because they can contract very quickly and for long periods of time. c.) White skeletal muscles have fewer mitochondria, and thus contain less energy for sustained contractions. d.)Your bicep is an example of white skeletal muscle.

White skeletal muscles have fewer mitochondria, and thus contain less energy for sustained contractions.

Acetylcholine, a __________, carries chemical signals from the ends of a motor neuron, across a synapse and to a muscle fiber. This sets the stage for events that lead to muscle contractions.

neurotransmitter