Chapter 6 Muscular System

What does endomysium cover?

an individual muscle cell

What unit contains the Z disk?

I band

When a skeletal muscle is fully contracted, the __________ are closer to the thick filaments.

Z discs

Acetylcholine is _________

a neurotransmitter that stimulates skeletal muscle

Muscles that perform opposite actions to one another are termed ________

antagonists

If muscles are not used what occurs?

atrophy

Neurotransmitters are released upon stimulation from a nerve impulse by the _____________

axon terminal of the motor neuron

Muscle tissue has the ability to shorten when adequately stimulated, a characteristic known as ________.

contractility

A smooth, sustained contraction is called ________.

fused, or complete tetanus

Smooth muscle cells are _________.

involuntary

One neuron and all the skeletal muscles it stimulates is known as a ________.

motor unit

The point of muscle attachment to an immovable or less movable bone is known as the _____________

origin

The plasma membrane of a skeletal muscle cell is called the _________

sarcolemma

The ____________ is an organelle that wraps and surrounds the myofibril and stores calcium

sarcoplasmic reticulum

What unit contains overlapping actin and myosin myofilaments?

A band

The gap between the motor neuron and the muscle fiber at the neuromuscular junction is called ____________

synaptic cleft

Epimysium covering on the outside of the muscle can blend into cordlike _________ or sheetlike ____________.

tendons; aponeuroses

The link of the myosin heads with the thick & filaments together during a contraction is called ____________

the cross bridges

Muscle cells that have striations & are branched, unicellular, and contract involuntarily __________

cardiac muscle

Myosin heads make _________ when they link the thick and thin filaments during a contraction.

cross bridges