Muscular System Review

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

False

Smooth muscle cells produce movement of the body and generate heat. True or False

False

What creates the alternating light and dark bands that provide the striation pattern on skeletal muscle tissue? A) sarcoplasm and sarcolemma B) Z discs and H zones C) A bands and I bands D) H zones and M lines E) thick filaments and myosin heads

C) A bands and I bands

Which method of regenerating ATP during muscle contraction can produce lactic acid? A) Creatine phosphate B) Direct phosphorylation C) Anaerobic glycolysis D) Oxidative phosphorylation E) Aerobic respiration

C) Anaerobic glycolysis

Which of these events must occur first to trigger the skeletal muscle to generate an action potential and contract? A) Sodium ions rush into the cell. B) Acetylcholinesterase (AchE) breaks down acetylcholine (ACh). C) The sodium-potassium pump restores sodium and potassium back to their initial positions. D) Acetylcholine (ACh) binds to receptors on the sarcolemma and allows passage of sodium ions into the cell. E) Potassium ions diffuse out of the muscle cell.

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

Which of the following is not> a function of the muscular system? A) Maintenance of posture B) Stabilization of joints C) Generation of heat D) Blood cell formation E) Production of movement

D) Blood cell formation

Botulinum toxin is produced by bacteria; it can cause flaccid paralysis in human muscle cells. Evaluate the following mechanisms to determine its mode of action. A) Botulinum toxin promotes the entry of sodium ions into muscle cells. B) Botulinum toxin prevents the exit of potassium ions from muscle cells. C) Botulinum toxin prevents the release of acetylcholinesterase. D) Botulinum toxin prevents the release of acetylcholine from axon terminals. E) Botulinum toxin promotes the release of acetylcholine from axon terminals.

D) Botulinum toxin prevents the release of acetylcholine from axon terminals.

The fastest mechanism for producing ATP is aerobic respiration. True or False

False

Aerobic, or endurance, exercise involves jogging or biking. True or False

True

Cardiac and skeletal muscle both possess striations. True or False

True

Cardiac muscle fibers are joined by special gap junctions called intercalated discs; these discs allow heart activity to be closely coordinated. True or False

True

The formation of cross bridges requires both calcium ions and ATP. True or False

True

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

True

What is required to form a cross bridge between a myosin head and an actin filament? A) Calcium ions and ATP B) Sodium ions C) Acetylcholine D) Sodium ions and ATP E) Potassium ions

A) Calcium ions and ATP

Which organelle stores calcium in muscle fibers? A) Sarcoplasmic reticulum B) Myofilament C) Sarcoplasm D) Sarcolemma E) Myofibril

A) Sarcoplasmic reticulum

Which term does >not describe smooth muscle cells? A) Skeletal B) Visceral C) Involuntary D) Nonstriated

A) Skeletal

What is the unstoppable electrical current that travels down the length of the entire surface of a sarcolemma? A) action potential B) acetylcholine C) neuromuscular junction D) neurotransmitter

A) action potential

The method that regenerates the most ATP during muscle activity is ________. A) aerobic pathway B) direct phosphorylation C) anaerobic pathway D) lactic acid pathway

A) aerobic pathway

The heads of the myosin myofilaments are called ________ when they link the thick and thin filaments together during skeletal muscle contraction. A) cross bridges B) neuromuscular junctions C) synapses D) motor units

A) cross bridges

A smooth, sustained contraction, with no evidence of relaxation, is called ________. A) fused, or complete, tetanus B) unfused, or incomplete, tetanus C) a twitch D) summing of contractions

A) fused, or complete, tetanus

What enzyme breaks down acetylcholine into acetic acid and choline to prevent continued contraction of the muscle fiber? A) sarcoplasmic reticulum B) acetylcholinesterase C) cross bridges D) calcium ions E) potassium ions

B) acetylcholinesterase

One neuron and all the skeletal muscles it stimulates is known as a ________. A) sarcoplasmic reticulum B) motor unit C) neuromuscular junction D) synaptic cleft

B) motor unit

The plasma membrane of a skeletal muscle cell is called the ________. A) sarcoplasm B) sarcolemma C) sarcomere D) myofilament E) sarcoplasmic reticulum

B) sarcolemma

The gap between the axon terminal of a motor neuron and the sarcolemma of a skeletal muscle cell is called the ________. A) neuromuscular junction B) synaptic cleft C) sarcomere D) motor unit E) cross bridge

B) synaptic cleft

Prior to surgery, a patient will be given a muscle relaxant. Evaluate the following drug descriptions and select the one that will promote muscle relaxation. A) Drug A increases an influx of calcium ions into the axon terminal. B) Drug B inhibits the breakdown of acetylcholine by preventing acetylcholinesterase from acting. C) Drug C decreases the binding of acetylcholine to its receptor. D) Drug D increases the release of calcium from the sarcoplasmic reticulum. E) Drug E promotes an increase in acetylcholine from synaptic vesicles.

C) Drug C decreases the binding of acetylcholine to its receptor.

According to the sliding filament theory, how does muscle contraction occur? A) Both thick and thin filaments shorten as the muscle contracts. B) Myosin heads attach and detach from thin filaments, causing thin filaments to shorten. C) Myosin heads form cross bridges and pull thin filaments, causing them to slide. D) A bands bunch up and shorten as myosin heads attach to thin filaments.

C) Myosin heads form cross bridges and pull thin filaments, causing them to slide.

Which of the following is composed mostly of the protein myosin? A) Light bands B) Thin filaments C) Thick filaments D) Z discs E) All myofilaments

C) Thick filaments

Which type of filament is anchored to the Z disc within a myofibril? A) H zone B) Cross bridges C) Thin filaments D) Thick filaments E) Myosin filaments

C) Thin filaments

Neurotransmitters are released upon stimulation from a nerve impulse from the ________. A) sarcolemma of the muscle cell B) thick filaments C) axon terminals of the motor neuron D) myofibrils E) sarcoplasmic reticulum

C) axon terminals of the motor neuron

Why are calcium ions necessary for skeletal muscle contraction? A) Calcium ions release the inhibition on Z discs.Calcium ions cause ATP binding to actin. B) Calcium ions bind to regulatory proteins on the myosin filaments, changing both their shape and their position on the thick filaments. C) Calcium ions increase the speed of the action potential transmitted along the sarcolemma. D) Calcium ions trigger the binding of myosin heads to actin filaments.

D) Calcium ions trigger the binding of myosin heads to actin filaments.

What is covered by the endomysium? A) smooth muscle only B) an entire muscle C) fascicles of muscle cells D) an individual muscle cell E) myofibrils

D) an individual muscle cell

Pufferfish contain a venom known as tetrodotoxin (TTX), which makes sodium channels stay closed. You'd expect a muscle cell treated with TTX to ________. A) produce action potentials in rapid sequence. B) operate the sodium-potassium pump more slowly. C) continue forming cross bridges. D) be unable to produce an action potential. E) produce contractions that are stronger than normal.

D) be unable to produce an action potential.

During skeletal muscle contraction, myosin heads bind actin filaments to form ________. A) H zones B) Z discs C) A bands D) cross bridges E) I bands

D) cross bridges

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? A) twitch B) fused, or complete, tetanus C) action potential D) graded response E) incomplete, or unfused, tetanus

D) graded response

The type of muscle tissue pictured in the figure is ________. A) striated B) skeletal muscle C) found only in the heart D) smooth muscle E) voluntary

D) smooth muscle

What must rush into a muscle cell to promote its depolarization? A) acetylcholinesterase B) calcium ions C) potassium ions D) sodium ions E) acetylcholine

D) sodium ions

Creatine phosphate (CP) functions within the muscle cells by ________. A) storing energy that will be transferred to ATP to resynthesize ADP as needed B) forming a temporary chemical compound with myosin C) forming a chemical compound with actin D) storing energy that will be transferred to ADP to resynthesize ATP as needed E) inducing a conformational change in the myofilaments

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

A sarcomere is ________. A) the area between two intercalated discs B) the wavy lines on the cell, as seen in a microscope C) a compartment in a myofilament D) the contractile unit between two Z discs E) the nonfunctional unit of skeletal muscle

D) the contractile unit between two Z discs

What is released by axon terminals into the synaptic cleft to stimulate a muscle to contract? A) Actin B) Potassium ions C) Sodium ions D) Myosin heads E) Neurotransmitter

E) Neurotransmitter

Which of the following is a type isometric exercise in which muscles increase in size and strength? A) Jogging B) Dancing C) Swimming D) Biking E) Pushing against a wall

E) Pushing against a wall

What condition results if muscles are not used, such as when immobilized in a cast for healing a broken bone? A) hypertrophy B) spina bifida C) scoliosis D) lordosis E) atrophy

E) atrophy