Unit 8: Muscular System

When a skeletal muscle fiber contracts, Question 4 options: a) the H bands and I bands get smaller. b) the zones of overlap get larger. c) the Z lines get closer together .d) the width of the A band remains constant. e) all of the above

) all of the above

Aerobic metabolism normally provides ________ percent of the ATP demands of a resting muscle cell. Question 8 options: a) 25 b) 50 c) 70 d) 95 e) 100

95

Which statement about the microscopic anatomy of skeletal muscle fibers is true? Question 6 options: a) Tubular extensions of the sarcolemma penetrate the fiber transversely. b) Cross striations result from alignment of thick and thin filaments. c) Each fiber has many nuclei. d) Muscle fibers are continuous from tendon to tendon. e) All are true.

All are true.

Which statement about excitation-contraction coupling is incorrect? Question 9 options: a) Calcium ion is released from the transverse tubule. b) Calcium ion is released from the sarcoplasmic reticulum .c) Tropomyosin moves to expose myosin binding sites on actin. d) Troponin binds calcium ion and signals tropomyosin to move. e) Relaxation requires uptake of calcium ions by the sarcoplasmic reticulum.

Calcium ion is released from the transverse tubule.

Which of the following is NOT true of muscle contraction? Question 4 options: a. A skeletal muscle fiber receives is stimulated by a nerve cell (neuron). b. Actin and myosin are the contractile proteins c. Sarcomeres are composed of myofilaments that slide across each other to cause contraction. d. Calcium ions bind to myosin filaments to expose the actin filaments.

Calcium ions bind to myosin filaments to expose the actin filaments.

The region of the sarcomere that always contains thin filaments is the Question 4 options: a) Z line. b) I band. c) H zone. d) A band.

I band.

How would a drug that blocks acetylcholine receptors at the motor end plate affect skeletal muscle? Question 12 options: a) It would make the muscles more excitable. b) It would produce uncontrolled muscle spasms. c) It would cause spastic paralysis (muscles are contracted and unable to relax). d) It would cause flaccid paralysis (muscles are relaxed and unable to contract).

It would cause flaccid paralysis (muscles are relaxed and unable to contract).

How would the loss of acetylcholinesterase from the neuromuscular junction affect skeletal muscle? Question 1 options: a) It would make the muscles less excitable .b) It would produce muscle weakness. c) It would cause spastic paralysis (muscles are contracted and unable to relax). d) It would cause flaccid paralysis (muscles are relaxed and unable to contract).

It would cause spastic paralysis (muscles are contracted and unable to relax).

The muscles of facial expression insert into skin or other muscles, not bones. Question 13 options: a) TRUE b) FALSE

TRUE

Which of the following motor units would produce the greatest tension? Question 10 options: a) a motor unit in a back muscle b) a motor unit in a hand muscle c) a motor unit in an eye muscle

a motor unit in a back muscle

A single motor neuron together with all the muscle fibers it innervates is called Question 5 options: a) an end foot. b) an end plate. c) a motor unit. d) a dermatome.

a motor unit.

Which of the following muscles would contract more forcefully? Question 11 options: a) a muscle receiving 10 to 15 action potentials per second b) a muscle receiving 20 to 25 action potentials per second

a muscle receiving 20 to 25 action potentials per second

What type of muscle assists an agonist by causing a like movement or by stabilizing a joint over which an agonist acts? Question 19 options: a) an antagonist b) a prime mover c) a synergist d) an agonist

a synergist

Triggering of the muscle action potential occurs after Question 1 options: a) acetylcholine binds to chemically gated channels in the motor end plate membrane. b) acetylcholinesterase binds to receptors on the end plate. c) the nerve action potential jumps across the neuromuscular junction. d) Any of the above can produce an action potential in the muscle cell.

acetylcholine binds to chemically gated channels in the motor end plate membrane.

The synaptic knobs contain vesicles filled with molecules of the neurotransmitter Question 12 options: a) epinephrine. b) norepinephrine. c) acetylcholine. d) antidiuretic hormone. e) all of the above

acetylcholine.

The most important factor in decreasing the intracellular concentration of calcium ion after contraction is Question 5 options: a) diffusion of calcium out of the cell. b) active transport of calcium into the sarcoplasmic reticulum. c) active transport of calcium into the synaptic cleft. d) diffusion of calcium into the sarcoplasmic reticulum.

active transport of calcium into the sarcoplasmic reticulum.

Creatine phosphate Question 6 options: a) cannot transfer its phosphate group to ADP. b) can replace ATP in binding to myosin molecules during contraction. c) acts as an energy reserve in muscle tissue. d) is only formed during strenuous exercise.

acts as an energy reserve in muscle tissue.

Damage to the pectoralis major would interfere with a person's ability to Question 15 options: a) extend the forearm. b) abduct the humerus. c) adduct the humerus. d) elevate the scapula. e) rotate the elbow.

adduct the humerus.

The muscle that adducts the thumb is the Question 14 options: a) adductor pollicis. b) abductor pollicis. c) extensor digitorum. d) flexor digitorum profundus.

adductor pollicis.

Compared to a typical body cell, skeletal muscle cells are Question 7 options: a) larger than normal cells. b) multinucleate. c) filled with cylindrical structures containing contractile proteins. d) capable of rapid shortening against a load. e) all of the above

all of the above

The muscles of the head and neck function in Question 20 options: a) nonverbal communication. b) feeding. c) controlling the eyes. d) all of the above e) none of the above

all of the above

The pectoralis major muscle inserts on the greater tubercle of the humerus. When it contracts, it produces Question 20 options: a) flexion. b) medial rotation .c) adduction. d) all of the above e) none of the above

all of the above

Which of the following is a function of skeletal muscle? Question 9 options: a) produce movement b) maintain posture c) maintain body temperature d) guard body entrances and exits e) all of the above

all of the above

Which of the following originates on the medial epicondyle of the humerus? Question 14 options: a) flexor carpi radialis b) flexor carpi ulnaris c) palmaris longus d) pronator teres. e) all of the above

all of the above

Which of these would lead to increased oxygen consumption? Question 4 options: a) increased heat production b) increased conversion of lactic acid to glucose c) increased aerobic respiration by muscle cells d) increased muscle activity e) all of the above

all of the above

What is a muscle that provides the major force for producing a specific movement called? Question 19 options: a) a synergist b) an agonist (prime mover) c) an antagonist d) a fixator

an agonist (prime mover)

Decreased blood flow to a muscle could result in all of the following, except Question 1 options: a) muscle fatigue. b) an oxygen debt. c) an increase in intracellular glycogen. d) an increase in intracellular lactic acid.

an increase in intracellular glycogen.

A muscle that opposes, or reverses, a particular movement is a(n) ________. Question 16 options: a) antagonist b) fixator c) synergist d) agonist (prime mover)

antagonist

Which of the following does not move the shoulder girdle? Question 17 options: a) pectoralis major b) brachialis c) rhomboid d) serratus anterior e) trapezius

brachialis

A muscle that inserts on the body of the mandible is probably involved in Question 18 options: a) kissing. b) blowing. c) chewing. d) frowning. e) spitting.

chewing.

The names of the muscles can indicate all of the following, except Question 16 options: a) the angle of the muscle relative to the long axis of the body. b) the action of the muscle. c) the location of the muscle. d) structural characteristics of the muscle. e) collagen content of the muscle.

collagen content of the muscle.

When a muscle is stimulated repeatedly at a high rate, the amount of tension gradually increases to a steady maximum tension. This is called Question 1 options: a) muscle tone. b) complete tetanus. c) a twitch. d) recruitment.

complete tetanus.

Perimysium is the: Question 4 options: a. epithelial tissue covering the epimysium. b. name given to the bundles of contractile fibers in a muscle .c. connective tissue surrounding the fascicles. d. name given to the fascia when referring to more than one muscle group.

connective tissue surrounding the fascicles.

Which of the following supports the sliding filament theory of muscle contraction? Question 2 options: a) constant distance between Z lines during contraction. b) decreased width of the H zone during contraction. c) increased width of the I band during contraction. d) decreased width of the A band during contraction.

decreased width of the H zone during contraction.

Synaptic vesicles containing neurotransmitters are released via ________ when the action potential arrives. Question 11 options: a) endocytosis b) apoptosis c) exocytosis d) hydrolysis

exocytosis

Muscles that insert on the olecranon process of the ulna can act to Question 18 options: a) flex the forearm. b) extend the forearm. c) abduct the forearm. d) adduct the forearm.

extend the forearm.

Superficial muscles that position or stabilize an organ are called Question 15 options :a) internus. b) extrinsic. c) profundus. d) intrinsic.

extrinsic.

The compound that serves as a source of energy for muscle cells is: Question 2 options: ADP. calcium phosphate. glycogen. lactic acid.

glycogen.

Which of the following is NOT a member of the hamstrings? Question 20 options: a) gracilis b) semitendinosus c) semimembranosus d) biceps femoris

gracilis

The infraspinatus has its insertion on the Question 17 options: a) greater tubercle of the humerus. b) tuberosity of the radius .c) near the spine d) clavicle and scapula.

greater tubercle of the humerus.

Hypertrophy can best be described as: Question 3 options: a wasting away of the muscle. a muscle that maintains a weak contraction. increase in muscle size. the movable point of attachment of the muscle.

increase in muscle size.

Damage to which of the following muscles would interfere most with the ability to breathe? Question 16 options: a) sternocleidomastoid b) rectus abdominis c) intercostals d) platysma

intercostals

Muscles located entirely within an organ are called Question 15 options: a) internus. b) extrinsic. c) profundus. d) intrinsic.

intrinsic.

The type of contraction in which the muscle fibers do not shorten is called Question 12 options: a) tetany. b) concentric. c) isotonic. d) isometric.

isometric

When a muscle contracts repeatedly and strenuously, which of the following would be most likely to accumulate? Question 8 options: pyruvic acidlactic acidcreatine phosphatecreatinine phosphatase ATP

lactic acid

Which of the following is NOT a muscle primarily involved in the breathing process? Question 13 options: a) diaphragm b) external intercostal c) internal intercostal d) latissimus dorsi

latissimus dorsi

The muscle weakness of myasthenia gravis results from Question 7 options: a) insufficient acetylcholine release from presynaptic vesicles. b) loss of acetylcholine receptors in the sarcolemma c) bacterial infection d) excessive acetylcholinesterase that destroys the neurotransmitter.

loss of acetylcholine receptors in the sarcolemma

The sternocleidomastoid muscle inserts on the ________. Question 14 options: a) sternum b) clavicle c) platysma d) mastoid process of the temporal bone

mastoid process of the temporal bone

The sternocleidomastoid inserts on the Question 17 options: a) occipital bone. b) clavicle. c) mastoid process. d) sternum. e) none of the above

mastoid process.

Muscles located close to the midline of the body may be called Question 18 options: a) rectus. b) distalis. c) proximal .d) medialis. e) lateralis.

medialis.

When acetylcholine binds to receptors at the motor end plate, the end plate membrane becomes Question 5 options: a) more permeable to sodium ions .b) less permeable to sodium ions. c) more permeable to calcium ions. d) less permeable to potassium ions.

more permeable to sodium ions.

During activities requiring aerobic endurance Question 2 options: a) glycolysis is the primary source of ATP. b) oxygen is not required. c) most of the muscle's ATP is produced in mitochondria. d) fatigue occurs in a few minutes.

most of the muscle's ATP is produced in mitochondria.

Receptors for acetylcholine are located on the Question 3 options: a) synaptic knob. b) motor end plate. c) sarcomere. d) synaptic cleft. e) transverse tubule.

motor end plate.

Interactions between actin and myosin filaments of the sarcomere are responsible for Question 8 options: a) muscle fatigue. b) the conduction of a signal toward the muscle fiber. c) muscle contraction .d) muscular dystrophy.

muscle contraction.

During the recovery period following exercise, all of the following are true, except Question 5 options: a) lactic acid is removed from muscle cells. b) the muscle restores it's energy reserves. c) muscle fibers are unable to contract. d) oxygen is consumed at above the resting rate.

muscle fibers are unable to contract.

In an isotonic contraction, Question 9 options: a) muscle tension exceeds the load and the muscle shortens to move the load. b) tension rises and falls but the muscle length is constant. c) the peak tension is less than the load. d) many twitches fuse into one.

muscle tension exceeds the load and the muscle shortens to move the load.

In which of the following would you expect the motor units to have the fewest muscle fibers? Question 12 options: a) muscles of the back b) calf muscles c) muscles that move the eyes d) thigh muscles

muscles that move the eyes

A condition that occurs most often in males and is a progressive disorder of muscle is: Question 7 options: a.Clostridium tetani. b.muscular dystrophy. c.hypertrophy d.hernia.

muscular dystrophy.

Skeletal muscle fibers are formed from embryonic cells called Question 6 options: a) sarcomeres. b) myofibrils. c) myoblasts. d) fascicles.

myoblasts.

Cross-bridges are formed by the Question 2 options: a) actin molecules. b) myosin molecules. c) troponin molecules. d) tropomyosin molecules. e) calcium ions.

myosin molecules.

Individuals who are engaged in repetitive hand movements such as typing or playing the piano may suffer wrist pain, especially during palmar flexion. All of the following are true concerning this condition, except that it Question 13 options: a) is called carpal tunnel syndrome. b) results from inflammation of the synovial tendon sheaths. c) never causes muscle weakness. d) results from inflammation of the carpal retinacula. e) irritates the median nerve.

never causes muscle weakness.

The skeletal muscle complex known as the triad consists of Question 10 options: a) actin, myosin, and filaments. b) one transverse tubule and two terminal cisternae. c) filaments, myofibrils, and sarcomeres. d) A bands, H bands, and I bands.

one transverse tubule and two terminal cisternae.

All of the following originate on the scapula, except the Question 18 options: a) pectoralis major. b) teres major. c) teres minor. d) subscapularis. e) supraspinatus.

pectoralis major.

The anterior muscle that inserts widely on the periosteum of the mandible and the skin of the cheek is the Question 19 options: a) temporalis. b) masseter. c) sternocleidomastoid d) platysma.

platysma.

Deep muscles are called Question 14 options: a) superficialis. b) extrinsic. c) profundus. d) intrinsic. e) externus.

profundus.

The muscle that pronates the forearm and opposes biceps brachii is the Question 19 options: a) brachialis. b) triceps brachii .c) pronator quadratus. d) latissimus dorsi.

pronator quadratus.

Which of the following describes the action of the serratus anterior? Question 15 options: a) adducts the arm b) adducts and flexes the humerus c) protracts the shoulder, abducts and medially rotates the scapula d) medial rotation of the humerus e) lateral rotation of the humerus

protracts the shoulder, abducts and medially rotates the scapula

The increase in muscle tension that is produced by increasing the number of active motor units is called Question 12 options: a) incomplete tetanus. b) complete tetanus. c) summation. d) recruitment.

recruitment.

Which of the following is not an extrinsic eye muscle? Question 19 options: a) inferior rectus b) rectus abdominis c) lateral rectus d) medial rectus e) superior oblique

rectus abdominis

Which of the following muscles has its insertion on the xiphoid process of the sternum? Question 20 options: a) internal oblique b) external intercostal c) rectus abdominis d) internal intercostal e) scalene

rectus abdominis

Nerve stimulation of a skeletal muscle is directly responsible for which ofthe following? Question 2 options: a.release of calcium ions from the sarcoplasmic reticulum b.removal of calcium ions from the actin molecule c.the striations of skeletal muscles d.the formation of ATP and ADP

release of calcium ions from the sarcoplasmic reticulum

The zygomaticus major muscle acts to Question 20 options: a) move the external ear. b) purse the lips. c) depress the lower lip. d) retract and elevate the corner of the mouth. e) close the eye.

retract and elevate the corner of the mouth.

Muscles of the rotator cuff include all of the following, except the Question 17 options: a) supraspinatus. b) infraspinatus. c) subscapularis. d) teres minor. e) rhomboid.

rhomboid.

The muscle that adducts and rotates the scapula laterally is the Question 13 options: a) rhomboid. b) levator scapulae. c) serratus anterior. d) pectoralis minor.

rhomboid.

After death, muscle fibers run out of ATP and calcium begins to leak from the sarcoplasmic reticulum into the sarcoplasm. This results in a condition known as Question 3 options: a) muscle cramp. b) oxygen debt. c) depolarization. d) rigor mortis.

rigor mortis.

The plasma (cell) membrane of skeletal muscle fibers is called the Question 10 options: a) sarcolemma. b) sarcomere. c) sarcoplasm .d) sarcoplasmic reticulum.

sarcolemma.

The only knee flexor that originates superior to the acetabulum is the Question 13 options: a) biceps femoris. b) gracilis. c) sartorius. d) semimembranosus.

sartorius.

Since each myofibril is attached at either end of the muscle fiber, when sarcomeres shorten, the muscle fiber Question 8 options: a) lengthens. b) shortens. c) weakens. d) not enough information to say

shortens.

Cardiac muscle tissue can best be described as: Question 3 options: smooth muscle. non-striated muscle. skeletal muscle. striated muscle.

striated muscle.

If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This is called Question 10 options: a) incomplete tetanus. b) complete tetanus. c) summation. d) recruitment.

summation.

Muscles visible at the body surface are often called Question 18 options: a) internus. b) superficialis. c) profundus. d) intrinsic.

superficialis.

The narrow space between the synaptic terminal and the muscle fiber is the Question 11 options: a) synaptic knob. b) motor end plate. c) motor unit. d) synaptic cleft.

synaptic cleft.

Each skeletal muscle fiber is controlled by a motor neuron at a single Question 7 options: a) synaptic knob. b) sarcomere. c) neuromuscular junction. d) transverse tubule.

synaptic knob.

A muscle that assists the muscle that is primarily responsible for a given action is a(n) Question 17 options: a) agonist. b) antagonist. c) synergist. d) originator.

synergist.

Muscles that are long and round in cross section are termed Question 16 options: a) longus. b) teres. c) longissimus. d) maximus.

teres

The advantage of having many nuclei in a skeletal muscle fiber is Question 3 options :a) the ability to contract. b) the ability to produce more ATP with little oxygen. c) the ability to store extra DNA for cell division. d) the ability to produce large amounts of the muscle proteins needed for muscle contraction.

the ability to produce large amounts of the muscle proteins needed for muscle contraction.

Which of the following is greater? Question 9 options: a) the concentration of calcium ion in the sarcoplasm of a resting muscle b) the concentration of calcium ion in the sarcoplasmic reticulum of a resting muscle

the concentration of calcium ion in the sarcoplasmic reticulum of a resting muscle

Which of the following interacts with ATP during muscle contraction? Question 5 options: a) actin molecules b) troponin molecules c) tropomyosin molecules d) the head portion of the myosin molecule

the head portion of the myosin molecule

Which of the following muscles is involved in crossing one leg over the other to produce the cross-legged position? Question 16 options: a) the gastrocnemius b) the sartorius c) all of the hamstrings d) the quadriceps femoris

the sartorius

Isometric contraction is: Question 6 options: a.the type of contraction in which there is no change in length of the muscle. b.the type of contraction in which there is pronounced change in length of the muscle. c.a condition that occurs in the muscle when the tension remains constant while the length of the muscle shortens. d.a condition that occurs in the muscle when the tension increases while the length of the muscle shortens.

the type of contraction in which there is no change in length of the muscle.

Which of the following become connected by myosin cross-bridges during muscle contraction? Question 11 options: a) thin filaments and thick filaments b) thin filaments and t-tubules c) z disks and actin filaments d) thick filaments and t-tubules

thin filaments and thick filaments

The action potential is conducted into the interior of the muscle fiber by Question 9 options: a) motor end plates. b) neuromuscular junctions. c) transverse tubules. d) sarcoplasmic reticulum.

transverse tubules.

The muscle that inserts on the acromion and scapular spine is the Question 15 options: a) serratus anterior. b) trapezius. c) sternocleidomastoid. d) pectoralis minor.

trapezius.

The muscle of the posterior arm which extends from the proximal end of thehumerus to the proximal end of the ulna is the: Question 8 options: deltoid. sternocleidomastoid .pectoralis major. triceps brachii.

triceps brachii.

The muscle that extends the arm while doing push-ups is the Question 14 options: a) deltoid .b) biceps brachii. c) brachialis. d) triceps brachii.

triceps brachii.

When calcium ion binds to troponin, Question 11 options: a) tropomyosin is moved to expose the active sites on actin. b) active sites on the myosin are exposed. c) actin heads will bind to myosin. d) muscle relaxation occurs.

tropomyosin is moved to expose the active sites on actin.

At rest, active sites on actin are blocked by Question 1 options: a) myosin molecules. b) troponin molecules. c) tropomyosin molecules. d) calcium ions. e) ATP molecules.

tropomyosin molecules.

What is the response to a single stimulus of a skeletal muscle called? Question 10 options: a) muscle tone b) tetanus c) twitch d) summation

twitch

Each thin filament consists of Question 7 options: a) two strands of protein called actin coiled helically around each other. b) chains of myosin molecules. c) six troponin molecules in a rod like structure. d) a rod-shaped structure with heads projecting from each end.

two strands of protein called actin coiled helically around each other.

Which of the following best describes the term Z line? Question 6 options: a) protein that accounts for elasticity of resting muscle b) mostly made of myosin molecules c) storage site for calcium ions d) where thin filaments are anchored

where thin filaments are anchored