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