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.

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.

Therefore, layers of _______ ________ enclose and separate all parts of a skeletal muscle

connective tissue

The muscle that adducts and flexes the arm is the

coracobrachialis.

Each muscle fiber within a fascicle lies within a layer of connective tissue in the form of a thin covering called _______.

endomysium

In order for muscle contraction to occur, cross-bridges form between:

myosin and actin.

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.

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.

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.

Fibers of muscles whose motor neurons are severed

may be replaced by fat or fibrous connective tissue.

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

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.

An example of a partial but sustained contraction is

muscle tone.

During muscle contraction ATP supplies energy for

myofilament movement.

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