ch 11

All muscle types will respond to an electrical stimulus because all muscle cells are________.

excitable

Skeletal muscle is called_________, because it is usually subject to conscious control.

voluntary

When a skeletal muscle lengthens, its_________ helps resist excessive stretching and subsequent injury to the muscle.

collagen

A myofilament that runs through the core of a thick filament and anchors it to a Z disc is called a(n)_________.

elastic filament

Which of the following is true regarding the sarcoplasmic reticulum?

It releases Ca2+ when a muscle fiber is excited.

Each T tubule is flanked by two_________.

terminal cisterns

Which of the following is predominately made up of myosin?

The thick filament

Which of the following marks the boundaries of a sarcomere?

Z discs

Which of the following contains overlapping thick and thin filaments?

A band

In skeletal muscle, the term that describes the alternating light and dark bands is____.

striations

Where is dystrophin, the protein that is defective in muscular dystrophy, normally found?

Between the outermost myofilaments and the sarcolemma of a muscle fiber

As you are lifting a box, someone places extra weight on top of it. For your muscle to continue contracting and lifting the box, the muscle must_________.

recruit more muscle fibers

To stimulate muscle contraction, acetylcholine is released from the___into the synaptic cleft.

synaptic vesicles

The axon terminal releases acetylcholine into the synaptic cleft, which is received by receptors on the motor end plate. Which structure does this describe?

The neuromuscular junction of a skeletal muscle

Which of the following best describes the resting membrane potential (RMP)?

The intracellular environment is negatively charged.

The absence or inhibition of acetylcholinesterase at a synapse would lead to_________.

tetanus

Which muscle type depends solely on the sarcoplasmic reticulum as its calcium source?

Skeletal muscle

During muscle contraction, binding sites for myosin are uncovered by the movement of_________.

tropomyosin

Cross bridges form between binding sites on actin myofilaments and_________.

myosin heads

An action potential for a muscle cell is propagated along the_________.

sarcolemma

Increased calcium ion permeability of the presynaptic terminal cell membrane is caused by_________.

an action potential

When acetylcholinesterase outlasts the release of acetylcholine from the synaptic vesicles, the skeletal muscle_________.

relaxes

The minimum stimulus needed to cause muscle contraction is called the_________.

threshold

A muscle twitch produces external tension and moves an object by shortening the muscles during the_________ phase.

contraction

If one nerve stimulus arrives at a muscle fiber so soon that the fiber does not relax at all from the previous twitch, the most likely result will be __________. This can only be achieved in the laboratory.

complete tetanus

If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be_________.

incomplete tetanus

Shortening a muscle while it maintains constant tension is called_________.

an isotonic contraction

Which of the following is true concerning isotonic eccentric contraction?

The muscle lengthens but tension remains constant.

Which of the following is true concerning isotonic concentric contraction?

The muscle shortens but tension remains constant.

In order for muscle to continue contracting during anaerobic fermentation, which of the following is essential?

Myokinase

The transfer of phosphate from CP to ADP is catalyzed by_________.

creatine kinase

Which of the following is not a purpose of the excess postexercise oxygen consumption (EPOC) in muscle?

To neutralize carbon dioxide buildup

Which fibers are primarily responsible for producing lactate?

Type IIB fast glycolytic fibers

Resistance exercise will most likely cause muscle to __________.

hypertrophy

Cardiac muscle has very little capacity for regeneration because it lacks_________.

satellite cells

Which muscle(s) can contract without the need for nervous stimulation?

Smooth and cardiac muscle

Which of the following is an accurate comparison of skeletal muscle to smooth muscle?

Smooth muscle contracts and relaxes more slowly.