Skeletal Structures and Functions

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Myofibrils contain:

Contractile proteins

Regulatory proteins

Structural proteins

All of these answers are correct. (correct)

Which of the following structures consists of a somatic motor neuron and all the skeletal muscle fibers it stimulates?

Neuromuscular junction

Sarcomere

Muscle unit

Motor unit (correct)

Increasing the number of active motor units within a skeletal muscle is called:

Wave summation.

Muscle tone.

Motor unit recruitment. (correct)

Flaccidity.

Which of following is a common characteristic of fast glycolytic (FG) skeletal muscle fibers?

High amount of glycogen in the sarcoplasm Signup and view all the answers

Smooth muscle cells differ from skeletal and cardiac muscle cells in that:

They can exhibit hyperplasia. Signup and view all the answers

Skeletal muscle cells are generally multinucleate because:

They were formed by fusion of more than one cell. Signup and view all the answers

Which of the following proteins is used to reinforce the sarcolemma and to help transmit the tension generated by the sarcomeres to the tendons?

Dystrophin Signup and view all the answers

Skeletal muscle contraction will continue to occur as long as which of the following chemicals are available in the cytosol of the muscle fiber?

Calcium ions and ATP Signup and view all the answers

The benefit of the creatine phosphate is that:

It can generate ATP for a short time even when oxygen is not present. Signup and view all the answers

If people are given an acetylcholinesterase inhibitor, they are likely to:

Become very weak. Signup and view all the answers

Calcium is used to trigger cross-bridge formation during which phase of muscle contraction?

Contraction phase Signup and view all the answers

While performing pull-ups, a person slowly lowers themselves from the "up" position. This is an example of:

D. An eccentric isotonic contraction. Signup and view all the answers

Which of the following types of muscle tissue contract(s) when excited by its/their own autorhythmic muscle fibers?

Cardiac muscle Signup and view all the answers

Which of the following correctly lists the sequence of structures that action potentials must move through to excite skeletal muscle contraction?

Axon of neuron, sarcolemma, T tubules Signup and view all the answers

In skeletal muscles, the combined amounts of creatine phosphate and ATP provide enough energy for the muscle to contract maximally for approximately:

15 seconds. Signup and view all the answers

To stimulate skeletal muscle contraction, acetylcholine must cross the __________ of the neuromuscular junction and bind to receptors on the motor end plate.

Synaptic cleft Signup and view all the answers

Which is a correct sequence of events in the onset of rigor mortis?

Cellular membranes become leaky -> calcium ions leak into the sarcoplasm -> myosin heads bind to actin -> muscles are in a state of rigidity Signup and view all the answers

In a neuromuscular junction, the effect of acetylcholine (ACh) binding to receptors on the motor end plate lasts only briefly due to:

Rapid destruction of ACh in the synaptic cleft by acetylcholinesterase Signup and view all the answers

Which of the following are commonly used to produce ATP during skeletal muscle contraction?

All of these choices are correct Signup and view all the answers

Which of the following is also referred to as the period of lost excitability in skeletal muscle fibers?

Refractory period Signup and view all the answers