The Muscular System

the muscle twitch is a brief and "jerky" movement, while the tetanic contraction is prolonged and continuous

A skeletal muscle twitch differs from a tetanic contraction in that ________.

fused, or complete, tetanus

A smooth, sustained contraction is called ________.

skeletal muscle tissue

Voluntary muscle tissue

atrophy

What condition results if muscles are not used, such as when immobilized in a cast for healing a broken bone?

knee extension

What is the main function of the quadriceps group?

scapular spine and clavicle

What is the origin of the deltoid muscle?

TRUE

When a muscle fiber contracts, the I bands diminish in size, the H zones disappear, and the A bands move closer together but do not diminish in length.

Z discs

When a skeletal muscle is fully contracted, the ________ are closer to the thick filaments.

hamstring group

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

rectus abdominis

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

tibialis anterior

Which muscle is an antagonist to gastrocnemius?

sarcomere

Which of the following can actually shorten during a muscle contraction?

hematopoiesis

Which of the following is NOT a function of the muscular system?

pushing against an immovable wall

Which of the following is an example of an isometric contraction?

biceps brachii and triceps brachii

Which of the following muscles are antagonists?

both masseter and temporalis

Which of the following muscles closes the jaw?

acetylcholine (ACh) causes temporary permeability to sodium

Which of these events must occur first to trigger the skeletal muscle to generate an action potential and contract?

temporalis

Which of these muscles is a synergist to masseter?

method of attachment of the muscle to bone

Which one of the following is NOT a criterion generally used in naming muscles?

thick filaments

Which one of the following is composed of myosin protein?

deltoid

Which one of the following muscles is involved in abduction of the arm at the shoulder joint?

skeletal

Which type of muscle tissue contracts most quickly upon stimulation?

abduction

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 ________.

storing energy that will be transferred to ADP to resynthesize ATP as needed

Creatine phosphate (CP) functions within the muscle cells by ________.

Label C

The perimysium wraps a fascicle of muscle cells and is represented by ________.

sarcolemma

The plasma membrane of a skeletal muscle cell is called the ________.

origin

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

FALSE

Thick filaments are made of a protein called actin.

calcium triggers the binding of myosin to actin

Why are calcium ions necessary for skeletal muscle contraction?

oxygen

Anaerobic glycolysis occurs without ________.

buccinator

A nursing infant develops a powerful sucking muscle that adults also use for whistling or blowing a trumpet called the ________.

motor unit

A motor neuron and all of the skeletal muscle fibers it stimulates are termed a ________.

synergist only

A muscle group that works with and assists the action of a prime mover is a(n) ________.

pectoralis major

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

FALSE

A muscle twitch results when the muscle is stimulated so rapidly that no evidence of relaxation is seen.

FALSE

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

the contractile unit between two Z discs

A sarcomere is ________.

TRUE

Abduction and adduction are antagonistic actions.

a neurotransmitter that stimulates skeletal muscle

Acetylcholine is ________.

TRUE

Aerobic respiration requires the use of oxygen to generate ATP.

TRUE

Aerobic, or endurance, exercise involves jogging or biking.

TRUE

All types of muscle have endomysium covering individual muscle cells.

sarcoplasmic reticulum

An elaborate and specialized network of membranes in skeletal muscle cells that function in calcium storage is the ________.

muscular dystrophy

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

oxygen

Anaerobic glycolysis requires ________ to make ATP.

FALSE

Bundles of muscle fibers are known as aponeuroses.

TRUE

Cardiac and skeletal muscle both possess striations.

isometric contractions

Contractions in which muscles shorten and produce movement are known as ________.

thin filaments

Cross bridges are created when myosin heads bind to ________.

actin filaments

During skeletal muscle contraction, myosin heads attach to binding sites associated with ________.

an individual muscle cell

Endomysium covers ________.

bind to receptors in the sarcolemma of the muscle cell

In ordIn order to excite a muscle cell, acetycholine must ________.er to excite a muscle cell, acetycholine must ________.

FALSE

Isometric contractions produce movement when filaments slide past one another and the muscle shortens.

TRUE

Muscle development in babies occurs in a cephalic/caudal direction.

cardiac muscle tissue

Muscle tissue composed of branching cells and intercalated discs

cardiac muscle tissue

Muscle tissue found only in the heart

contractility

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

smooth muscle tissue

Muscle tissue that activates arrector pili muscles to stand hairs on end

smooth muscle tissue

Muscle tissue that forms valves to regulate the passage of substances through internal body openings

skeletal muscle tissue

Muscle tissue that is multinucleate

antagonists

Muscles that perform opposite actions to one another are termed ________.

axon terminals of the motor neuron

Neurotransmitters are released upon stimulation from a nerve impulse by the ________.

motor unit

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

iliopsoas

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

FALSE

Plantar flexion at the ankle joint is accomplished by the tibialis anterior muscle.

extensor digitorum longus

Sandra is playing the piano for her recital. Which muscle is NOT involved in the movement of her hands and/or fingers ________.

involuntary

Smooth muscle cells are ________.

cardiac muscle

Striated involuntary muscle tissue found in the heart is ________.

cardiac

Striated involuntary muscle tissue is classified as ________ muscle.

FALSE

Supination and pronation refer to up and down movements of the foot at the ankle.

Label A

The A band within a skeletal muscle fiber is indicated by ________.

Label D

The H zone, located within the A band, lacks thin filaments and is represented by ________.

Label B

The I band within a skeletal muscle fiber is indicated by ________.

sarcoplasmic reticulum

The ________ is an organelle that wraps and surrounds the myofibril and stores calcium.

circular

The arrangement of fascicles in orbicularis oris is ________.

insufficient intracellular quantities of ATP due to excessive consumption

The condition of skeletal muscle fatigue can be best explained by ________.

TRUE

The deepest muscle of the abdominal wall is the transversus abdominis.

FALSE

The deltoid is a prime mover of arm adduction.

TRUE

The deltoid muscle is a common site for intramuscular injections.

TRUE

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

Label B

The endomysium that wraps individual muscle fibers is indicated by ________.

tendons; aponeuroses

The epimysium covering on the outside of the muscle can blend into cordlike ________ or sheetlike ________.

Label A

The epimysium is represented by ________.

FALSE

The fastest mechanism for producing ATP is aerobic respiration.

synaptic cleft

The gap between the axon terminal of a motor neuron and the sarcolemma of a skeletal muscle cell is called the ________.

synaptic cleft

The gap between the motor neuron and the muscle fiber it supplies at the neuromuscular junction is called the ________.

FALSE

The hamstring group inserts into the distal tibia.

extension; flexion

The hamstring group is the prime mover of thigh ________ and knee ________.

cross bridges

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

origin

The least movable point of muscle attachment to a bone is termed its ________.

a sliding of thin filaments past thick filaments

The mechanical force of contraction is generated by ________.

adduction

The movement opposite to abduction is ________.

Label D

The muscle fiber (cell) is indicated by ________.

orbicularis oculi

The muscle that closes each eye is the ________.

Label C

The myofilament composed of actin is indicated by ________.

TRUE

The neurotransmitter used by the nervous system to activate skeletal muscle cells is acetylcholine.

deltoid

The prime mover of arm abduction is the ________ muscle.

TRUE

The sarcoplasmic reticulum wraps like a sleeve around the myofibril and stores and releases calcium.

TRUE

The striations seen in skeletal muscle are actually alternating dark A and light I bands.

smooth muscle

The type of muscle tissue pictured in Figure 6.3 is ________.