ANP ch 8

The sarcomere, the basic unit of skeletal muscle, extends from A) A band to A band B) M line to M line C) H band to H band D) Z line to Z line

D) Z line to Z line

When a nerve impulse reaches the end of a motor neuron, A) the number of synaptic vesicles increases B) muscle fibers stretch C) calcium ions move out of the cytoplasm of the neuron D) acetylcholine is released

D) acetylcholine is released

The muscle that compresses the cheeks inward when it contracts is the A) orbicularis oris B) epicranius C) platysma D) buccinator

D) buccinator

Which of the following is not a characteristic of smooth muscle cells? A) some are responsive to hormones B) contraction is triggered by an influx of calcium ions C) stimulation by acetylcholine or norepinephrine D) highly organized arrangement of actin and myosin filaments

D) highly organized arrangement of actin and myosin filaments

Muscles that are involved in chewing are attached to the A) maxilla B) mandibular process of the temporal bone C) zygomatic bone D) mandible

D) mandible

Antagonistic muscles A) are always located on the same side of the body as the prime mover B) have different speeds and strengths of contraction C) produce extension rather than abduction D) perform movements opposite to those performed by the prime mover

D) perform movements opposite to those performed by the prime mover

Muscles produce the majority of the heat of the body. A) True B) False

true

During high intensity exercise, muscle fibers rely upon what process for energy? A) aerobic respiration B) increased metabolism of glucose C) anaerobic respiration D) increased blood supply

C) anaerobic respiration

The connective tissue that surrounds individual muscle fibers is called A) perimysium B) epimysium C) endomysium D) elastin

C) endomysium

The connective tissue that surrounds entire muscles is A) perimysium B) endomysium C) epimysium D) elastin

C) epimysium

Muscle fatigue can be caused by all of the following except A) lowering of pH due to lactic acid build-up B) interruption of blood supply C) formation of a cramp D) lack of acetylcholine

C) formation of a cramp

The rapidity with which an impulse spreads in cardiac muscle is due to A) increased amounts of neurotransmitters B) the presence of striated muscle fibers C) intercalated disks between muscle fibers D) the property of excitability

C) intercalated disks between muscle fibers

The strength of a muscle in response to different levels of stimulation is determined by the A) level of stimulation delivered to individual muscle fibers B) number of fibers that respond in each motor unit C) number of motor units receiving a threshold stimulus D) characteristics of each muscle group

C) number of motor units receiving a threshold stimulus

Peristalsis is due to which of the following characteristics of smooth muscle? A) excitability B) automaticity C) rhythmicity D) lack of innervation

C) rhythmicity

The dark bands in skeletal muscle that contribute to its striated appearance are known as A) A bands B) Z bands C) H bands D) I bands

A) A bands

Choose the true statement regarding skeletal muscle cells. A) Another term for a skeletal muscle cell is muscle fiber. B) Each skeletal muscle cell has one nuclei and mitochondria. C) The muscle cell membrane is called the sarcoplasm. D) Skeletal muscle cells never extend the full length of a muscle.

A) Another term for a skeletal muscle cell is muscle fiber.

The light bands in skeletal muscle that contribute to its striated appearance are known as A) I bands B) Z bands C) H bands D) A bands

A) I bands

During muscle contraction, the head of myosin cross-bridges attach to actin binding sites and bend slightly, pulling the actin filament toward the center of the sarcomere. A) True B) False

A) True

The psoas major and iliacus muscles flex the thigh. A) True B) False

A) True

The severity of muscle strain depends on the number of muscle fibers that are damaged. A) True B) False

A) True

When a skeletal muscle contracts, the insertion is pulled toward the origin. A) True B) False

A) True

t is possible for a skeletal muscle to be both synergist and antagonist to another muscle. A) True B) False

A) True

Muscle tone refers to A) a state of sustained, partial contraction of muscles that is necessary to maintain posture B) a feeling of well-being following exercise C) the ability of a muscle to maintain contraction against an outside force D) the condition athletes attain after intensive training

A) a state of sustained, partial contraction of muscles that is necessary to maintain posture

Which muscle produces plantar flexion? A) fibularis longus B) fibularis tertius C) tibialis anterior D) extensor digitorum longus

A) fibularis longus

Which of the following is not found at the end of the motor axon at the neuromuscular junction? A) many nuclei B) synaptic vesicles C) abundant mitochondria D) a cleft between the end and the muscle fiber

A) many nuclei

All of the following muscles flex the knee except A) rectus femoris B) semitendinosus C) semimembranosus D) biceps femoris

A) rectus femoris

When the cross-bridge of the myosin molecule forms linkages with actin filaments and bend, the result is A) shortening of the muscle fiber B) creation of a high energy bond C) membrane polarization D) release of acetylcholine

A) shortening of the muscle fiber

When the cross-bridge of the myosin molecule forms linkages with actin filaments, the result is A) shortening of the muscle fiber B) creation of a high energy bond C) membrane polarization D) release of acetylcholine

A) shortening of the muscle fiber

ATPase is stored in A) the globular portion of the myosin filament B) the actin filament helix C) transverse tubules D) muscle cell cytoplasm

A) the globular portion of the myosin filament

Choose the true statement regarding skeletal muscle cells. A) Another term for a skeletal muscle cell is myofibril. B) Each skeletal muscle cell has many nuclei and mitochondria. C) The muscle cell membrane is called the sarcoplasm. D) Skeletal muscle cells never extend the full length of a muscle.

B) Each skeletal muscle cell has many nuclei and mitochondria.

A motor neuron connects to a single muscle fiber. A) True B) False

B) False

An influx of potassium ions into the muscle fiber is responsible for cross-bridging of actin and myosin filaments. A) True B) False

B) False

During a tetanic contraction, all motor units in a muscle have been recruited. A) True B) False

B) False

Layers of connective tissue that extend into muscle and form compartments within the muscle are fascicles. A) True B) False

B) False

Oxygen debt is only the amount of oxygen needed to convert lactic acid into glucose after strenuous exercise. A) True B) False

B) False

Oxygen is stored in muscle tissue in molecules of hemoglobin located near mitochondria. A) True B) False

B) False

The sarcoplasmic reticulum is composed of invaginations of the muscle cell membrane that contain extracellular fluid. A) True B) False

B) False

A fibrous, flattened, sheet-like of connective tissue that connects a muscle to another muscle is known as A) fascia B) an aponeurosis C) a tendon sheath D) a broad ligament

B) an aponeurosis

A fibrous, flattened, sheet-like tendon is known as A) fascia B) an aponeurosis C) a tendon sheath D) a broad ligament

B) an aponeurosis

Not using a muscle will result in A) hypertrophy B) atrophy C) dystrophy D) mystrophy

B) atrophy

The primary flexor of the forearm is the A) internal oblique B) biceps brachii C) biceps femoris D) triceps brachii

B) biceps brachii

The shoulder muscle that abducts the upper arm and can both flex and extend the humerus is the A) biceps brachii B) deltoid C) infraspinatus D) supraspinatus

B) deltoid

The insertion of the sternocleidomastoid is the A) anterior surface of the sternum B) mastoid process of the temporal bone C) occipital bone D) spinous processes of the lower cervical vertebrae

B) mastoid process of the temporal bone

The result of summation and recruitment together is A) hypotonic contraction B) sustained tetanic contraction C) muscle tone D) muscle hypertrophy

B) sustained tetanic contraction

Which of the following is not characteristic of the motor end plate on a muscle fiber? A) many nuclei B) synaptic vesicles C) abundant mitochondria D) extensive folding of the sarcolemma

B) synaptic vesicles

Muscles that assist the prime mover in producing a movement are called A) antagonists B) synergists C) potentiators D) agonists

B) synergists

ATPase is stored in A) sarcoplasmic reticulum B) the globular portion of the myosin filament C) transverse tubules D) muscle cell cytoplasm

B) the globular portion of the myosin filament

The insertion of the temporalis is the coracoid process of the mandible. A) True B) False

false

Creatine phosphate stores energy that is used to convert ADP to ATP during muscle contraction. true false

true