Chapter 6 Anatomy Test

Located within a myofibril

A band

What creates the alternating light and dark bands that provides the striation pattern on skeletal muscle tissue?

A bands and I bands

What is acetylcholine?

A neurotransmitter that stimulates skeletal muscle to contract

What event must occur first to trigger the skeletal muscle to generate an action potential and contract?

Acetylcholine (ACh) binds to receptors on the sarcolemma and allows passage of sodium ions into the cell

A neuromuscular junction consists of one neuron and all the skeletal muscles it stimulates

False

Located within the A band; lacks thin filaments

H zone

What is released by axon terminals into the synaptic cleft to stimulate a muscle to contract?

acetylcholine

What enzyme breaks down acetylcholine into acetic acid and choline to prevent continued contraction of the muscle fiber?

acetylcholinesterase (AChE)

What is the unstoppable electrical current that travels down the length of the entire surface of a sarcolemma?

action potential

Which movement is opposite to abduction?

adduction

Which muscle group adducts the thighs?

adductor group

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 muscles are antagonists of each other?

biceps brachii and triceps brachii

Like the biceps brachii muscle, which muscle is a prime mover in elbow flexion?

brachialis

A skeletal muscle twitch differs from a tetanic contraction in that

brief and "jerky" movement; tetanic is prolonged and continuous

Striated involuntary muscle tissue is classified as ________ muscle.

cardiac

Striated involuntary muscle tissue found in the heart is

cardiac muscle

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

contractility

The heads of the myosin myofilaments are called ________ when they link the thick and thin filaments together during skeletal muscle contraction.

cross bridges

Which muscle forms the curved calf of the posterior leg?

gastrocnemius

Skeletal muscle, as a whole, can generate different amounts of force, and different degrees of shortening, in response to stimuli. What is this concept called?

graded response

Which muscle group includes the biceps femoris, semimembranosus, and semitendinosus?

hamstring group

Paralysis of which of the following would make an individual unable to flex the hip?

iliopsoas

Type of isometric exercise in which muscles increase in size and strength?

lifting weights

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

motor unit

An inherited disease that causes muscles to degenerate and atrophy is known as

muscular dystrophy

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

origin

A muscle located on the ventral (anterior) side of the body

pectoralis major

The condition of skeletal muscle fatigue can best be explained by

the inability of the muscle to contract even if it is being stimulated

Jason injured his hamstring muscle group during football practice. He will be unable to perform ____

thigh extension and knee flexion

Which of these muscles is the prime mover of elbow extension?

triceps brachii

Abduction and adduction are antagonistic actions

True

Cardiac and skeletal muscle both possess striations

True

Muscle development in babies occurs in a superior/inferior direction

True

The effect of the neurotransmitter on the muscle cell membrane is to temporarily modify its permeability of ions such as Na+ and K+

True

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

Which muscle helps compress the abdominal contents during defecation or childbirth?

rectus abdominis

The plasma membrane of a skeletal muscle cell is called the

sarcolemma

Which type of muscle tissue contracts most quickly upon stimulation

skeletal

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 sarcolemma of a skeletal muscle cell is called the

synaptic cleft