Chapter 9 Muscular Homework
These chemicals diffuse across a small gap between the neuron and muscle fiber called the _______ _______.
synaptic cleft
A muscle that assists the agonist is a(n)
synergist
Transverse tubules
transmit muscle impulses into the cell interior.
Therefore, layers of _______ ________ enclose and separate all parts of a skeletal muscle
connective tissue
Each muscle fiber within a fascicle lies within a layer of connective tissue in the form of a thin covering called _______.
endomysium
The first event in muscle fiber contraction is that
acetylcholine is released from the end of the motor neuron.
Myofibrils are composed primarily of
actin and myosin.
A muscle fiber exposed to a series of stimuli of increasing frequency combines individual twitches (summation) which results in
complete sustained contraction.
The muscle that adducts and flexes the arm is the
coracobrachialis.
Fibers of muscles whose motor neurons are severed
may be replaced by fat or fibrous connective tissue.
A weightlifter uses muscles so the muscles exert more than 75% of their maximum tension, This stimulates
muscle fibers developing new filaments of actin and myosin.
During muscle contraction ATP supplies energy for
myofilament movement.
In order for muscle contraction to occur, cross-bridges form between:
myosin and actin.
Regina began an exercise program six months ago, and the muscles of her upper limbs and lower limbs are more prominent. Exercise can lead to formation of new muscle by
stimulating skeletal muscle cells to release IL-6, which stimulates satellite cells to divide, producing more muscle cells.
The binding of the chemicals to the muscle cell causes an electrical impulse to travel along the sarcolemma and down the _______ tubules.
transverse
The triangle of auscultation, commonly used to hear sounds of respiratory organs, is located near the border of the
trapezius and latissimus dorsi.
What is the name of the neurotransmitter used at a skeletal neuromuscular junction?
Acetylcholine
Which of the following statements is correct?
Actin filaments slide along myosin filaments.
Transverse (T) tubules are invaginations of the sarcolemma of a muscle cell.
True
Which muscle group is composed of mainly slow-twitch (type I) fibers?
Erector spinae muscles of the back
Which of the following best describes the role of calcium in muscle contraction?
It binds to troponin, moving tropomyosin, so that myosin heads can bind to actin.
The characteristic reddish brown color of skeletal muscle comes from which substance?
Myoglobin
Which of the following is not true?
Red fibers have fewer mitochondria than white.
People with myasthenia gravis have a deficiency of
acetylcholine receptors
The chemical used at the junction with a skeletal muscle is _______.
acetycholine
The muscle that causes an action is the
agonist
Cardiac muscle
all of the above.
Functions of muscles include
all of the above.
Myasthenia gravis is
an autoimmune disorder.
The muscle that opposes a particular action is called the
antagonist
An electrical impulse travels into the interior of a muscle fiber:
by way of the transverse tubules.
The layer of connective tissue that closely surrounds a skeletal muscle is called the ________.
epimysium
A gluteal gait, in which a person walks with a waddling limp, is usually caused by a disorder of the
gluteus medius and gluteus minimus.
The structures that connect cardiac muscle cells are
intercalated discs.
In a recording of a muscle twitch, the delay between the time a stimulus is applied and the time the muscle responds is called the
latent period.
Threshold stimulus is the
minimum strength of stimulation required to contract a muscle fiber
The chemicals then bind to receptors located on the _____ ______ ______, a specialized area of the sarcolemma.
motor end plate
At a neuromuscular junction, the muscle fiber membrane folds, forming a
motor end plate.
At this junction, the ________ _______ releases a type of chemical called a ________.
motor neuron; neurotransmitter
An example of a partial but sustained contraction is
muscle tone.
The discoloration and swelling of a muscle strain is due to
ruptured blood vessels
The striated appearance of skeletal muscle fibers results from the
sarcomere organization.
Muscle fibers are basically a collection of
sarcomeres
An electrical impulse traveling along the sarcolemma and into transverse tubules causes calcium ions to diffuse from the ________ into the ________.
sarcoplasmic reticulum; sarcoplasm
Both acetylcholine and norepinephrine can affect
smooth muscle contraction.
Creatine phosphate
supplies energy for the synthesis of ATP.
The functional connection between a neuron and a skeletal muscle fiber is a
synapse
The site where the neuron communicates with the muscle fiber is called a ________.
synapse
The functional unit of muscle contraction is
the sarcomere.
Calcium ions bind to ______ in order to initiate a muscle contraction.
troponin
In order for a skeletal muscle fiber to contract, calcium must bind to:
troponin
Tawanda finishes a sprint and suffers great pain in her calf muscles. Her muscle cramps are most likely due to a temporary deficit of
ATP
Another layer of connective tissue, called the _______, extends inward from the epimysium and separates the muscle tissue into small sections. These sections contain bundles of skeletal muscle fibers called _______.
perimysium; fascicles