Chapter 6 Test
what creates the alternating light and dark bands that provides the striation patten on skeletal muscle tissue?
A bands and I bands
What is acetylcholine?
a neurotransmitter that stimulates skeletal muscle to contract
what is released by axon terminals into they synaptic cleft to stimulate a muscle to contract?
acetylcholine
Which of these events must occur first to trigger the skeletal muscle to generate an action potential and contract?
acetylcholine binds to receptors on the sarcolemma and allows passage of sodium ions into the cell
enzyme that breaks down acetylcholine
acetylcholinesterase
what enzyme breaks down acetylcholine into acetic acid and choline to prevent continued contraction of the muscle fiber?
acetylcholinesterase
during skeletal muscle contraction, to what do myosin heads bind?
actin filaments
What is the unstoppable electrical current that travels down the length of the entire surface of a sarcolemma?
action potential
electrical current that travels the length of the sarcolemma that results in the contraction of the muscle fiber
action potential
which movement is opposite to abduction?
adduction
what is covered by the endomysium?
an individual muscle cell
which method of regenerating ATP during muscle contraction can produce lactic acid?
anaerobic glycolysis
muscles that perform opposite actions to one another are termed...
antagonists
what condition results if muscles are not used such as when immobilized in a cast for healing a broken bone?
atrophy
neurotransmitters are released upon stimulation from a nerve impulse from the...
axon terminals of the motor neuron
which of the following is NOT a function of the muscular system?
blood cell formation
the sarcoplasmic reticulum stores this chemical
calcium ions
Why are calcium ions necessary for skeletal muscle contraction?
calcium ions trigger the binding of myosin heads to actin filaments
striated involuntary muscle tissue found in the heart is ...
cardiac muscle
striated involuntary muscle tissue is classified as...
cardiac muscle
muscle tissue composed of branching cells and intercalated discs
cardiac muscle tissue
muscle tissue found only in the heart
cardiac muscle tissue
muscle tissue has the ability to shorten when adequately stimulated, a characteristic known as...
contractility
the heads of the myosin filaments are called (BLANK) when they link the thick and thin filaments together during skeletal muscle contraction?
cross bridges
according to the sliding filament theory, how does muscle contraction occur?
myosin heads form cross bridges and pull thin filaments causing them to slide
The point of muscle attachment to an immovable or less movable bone is known as the (BLANK).
origin
which of the following is an example of an isometric contraction?
pushing against an immovable wall
the plasma membrane of a skeletal muscle cell is called the...
sarcolemma
what organelle wraps and surrounds the myofibril and stores calcium?
sarcoplasmic reticulum
which type of muscle tissue contracts most quickly upon stimulation?
skeletal
muscle tissue that is multinucleate
skeletal muscle tissue
muscle tissue that maintains posture, body position, and stabilizes joints
skeletal muscle tissue
voluntary muscle tissue
skeletal muscle tissue
Performs very slow, sometimes rhythmic, contractions
smooth muscle tissue
muscle tissue that dilates and constricts the pupils of our eyes
smooth muscle tissue
chemical that enters a muscle upon cell excitation
sodium ions
what must rush into a muscle cell to promote its depolarization?
sodium ions
creatine phosphate functions within the muscle cells by...
storing energy that will be transferred to ADP to resynthesize ATP as needed
The gap between the axon terminal of a motor neuron and the plasma membrane of a neighboring muscle cell
synaptic cleft
the gap between the axon terminal of a motor neurons and the sarcolemma of a skeletal muscle is called the...
synaptic cleft
a sarcomere is...
the contractile unit of skeletal muscle
a skeletal muscle twitch differs from a tetanic contraction in that...
the muscle twitch is a brief and "jerky" movement, while the tetanic contraction is prolonged and continues
which one of the following is composed mostly of protein myosin?
thick filaments
While doing "jumping jacks" during an exercise class, your arms and legs move laterally away from the midline of your body. This motion is called...
abduction
Specific neurotransmitter that stimulates skeletal muscle cells
acetylcholine
a smooth, sustained contraction, with no evidence of relaxation is called...
fused, or complete, tetanus
anaerobic glycolysis requires (BLANK) to make ATP
glucose only
contractions in which muscles shorten and produce movement are known as...
isotonic contractions
A motor neuron and all of the skeletal muscle cells it stimulates is called
motor unit
one neuron and all the skeletal muscles it stimulates is known as...
motor unit