A&P Mastering ch. 9 &10

Place the following events of excitation in the correct order. 1) ion channels on the sarcolemma open and sodium ions enter the muscle fiber 2) the entry of sodium ions into the muscle fiber depolarizes the sarcolemma locally 3) acetylcholine is released from vesicles in the motor neuron into the synaptic cleft 4) an action potential arrives at the axon terminal of a motor neuron 5) acetylcholine binds to ligand-gated sodium ion channels in the motor end plate 3, 4, 5, 1, 2 4, 3, 5, 1, 2 4, 5, 3, 2, 1 2, 4, 3, 5, 1

4, 3, 5, 1, 2

What do skeletal muscle tissue and cardiac muscle tissue share in common? Both skeletal and cardiac muscle tissues possess intercalated discs. Both skeletal and cardiac muscle tissues are striated. Both skeletal and cardiac muscle tissues are voluntary. Both skeletal and cardiac muscle tissues perform peristalsis.

Both skeletal and cardiac muscle tissues are striated

What do skeletal muscle contractions share in common with smooth muscle contractions? Both types of contractions result from thick and thin filaments sliding past one another. Both types of contractions do not require calcium ions for a contraction to occur. Both types of contractions generate little force or a weak force. Both types of contractions consume very little ATP.

Both types of contractions result from thick and thin filaments sliding past one another.

hich statement best describes the function of myoglobin? Myoglobin hydrolyzes ATP. Myoglobin stores oxygen in muscle cells. Myoglobin catabolizes glycogen. Myoglobin is a source of ATP for muscles.

Myoglobin stores oxygen in muscle cells.

Which of the following is a characteristic of smooth muscle? It can be controlled voluntarily. Smooth muscle cells contain actin and myosin. Muscle contraction does not depend on calcium ions. It has striations and sarcomeres.

Smooth muscle cells contain actin and myosin.

What happens when troponin and tropomyosin block the active sites of actin? The muscle produces a weak contraction. The muscle contraction increases tension. The muscle contraction reaches peak tension. The muscle relaxes.

The muscle relaxes.

During muscle contraction, myosin crossbridges bind to active sites on: troponin. tropomyosin. actin T-tubules.

actin

Part complete Which of the following muscles is named for its action? biceps brachii gluteus maximus adductor magnus deltoid

adductor magnus

A muscle that opposes or slows an action is called a(n) __________. agonist synergist fixator antagonist

antagonist

Triceps brachii and biceps brachii perform opposing actions and are classified as: synergists. antagonists. prime movers. agonists.

antagonists.

In response to physical inactivity, we expect to see muscles: increase the diameter of the muscle fiber. atrophy. hypertrophy. increase numbers of myofibrils.

atrophy.

The binding of a myosin head to an actin molecule is termed a: power stroke. synaptic cleft. crossbridge. triad.

crossbridge.

Where should most of the potassium ions be located when a muscle cell is at rest? extracellular fluid tranverse tubules (T-tubules) cytosol of the muscle cell sarcoplasmic reticulum

cytosol of the muscle cell

If the Na+ voltage-gated channels in a muscle cell open, what will be the result? repolarization The same result happens as if K+ voltage-gated channels have opened. The cell will remain at resting membrane potential. depolarization

depolarization

Which of the following wraps and surrounds an individual skeletal muscle fiber? endomysium perimysium sarcoplasmic reticulum epimysium

endomysium

During the recovery period after exercise, we breathe deeper and faster. This increased rate of respiration is known as: oxidative catabolism. muscle fatigue. lactic acid buildup. excess postexercise oxygen consumption (EPOC).

excess postexercise oxygen consumption (EPOC).

A group of skeletal muscle fibers together with the surrounding perimysium form a(n): ligament. endomysium. myofibril. fascicle.

fascicle.

A muscle that anchors a bone in place to make the movement more efficient is a(n) __________. agonist fixator synergist antagonist

fixator

When muscle fibers are stimulated so frequently they do not have an opportunity to relax, they are experiencing: fused or complete tetanus. unfused or incomplete tetanus. wave summation. twitch.

fused or complete tetanus.

What is the basic function of all muscle tissue? generate muscle tension stabilize joints produce voluntary contractions regulate body temperature

generate muscle tension

The type of contraction in which length of the muscle fibers do not change is called: tetany. isometric. isotonic eccentric. isotonic concentric.

isometric.

What type of contraction requires the greatest amount of tension? isotonic eccentric contraction isometric contraction isotonic concentric contraction miometric contraction

isotonic eccentric contraction

The immediate result of acetylcholine binding to receptors on the motor end plate is_________. local depolarization of the sarcolemma local repolarization of the sarcolemma the axon propagates an action potential the sarcolemma remains at its resting membrane potential

local depolarization of the sarcolemma

The folded region of sarcolemma found at the neuromuscular junction (NMJ) is called the_________. motor end plate sarcoplasmic reticulum axon terminal transverse tubule

motor end plate

Where are receptors for acetylcholine located? triad motor end plate axon terminal sarcomere

motor end plate

Which of the following proteins is a component of thick filaments? myosin actin troponin tropomyosin

myosin

During the power stoke of muscle contraction__________. myosin heads attach to actin's active sites ATP breaks the attachment of myosin to actin actin heads pull on the Z-disks of the sarcomere myosin heads pull actin toward the center of the sarcomere

myosin heads pull actin toward the center of the sarcomere

The synapse of a motor neuron with a muscle fiber is known as the: neuromuscular junction. synaptic bulb. motor end plate. synaptic cleft.

neuromuscular junction.

Which of the following promotes the depolarization stage? hydrolysis of ATP closure of voltage-gated sodium ion channels opening of voltage-gated potassium ion channels and potassium ions exit the cell opening of voltage-gated sodium ion channels and sodium ions enter the cell

opening of voltage-gated sodium ion channels and sodium ions enter the cell

The less-moveable, anchoring point on a bone is called the __________. joint fulcrum insertion origin

origin

Through which ATP-generating mechanism can long-lasting muscle contractions be sustained? anaerobic catabolism glycolysis creatine phosphate reaction oxidative catabolism

oxidative catabolism

A muscle cell experiencing resting membrane potential is: polarized. more negatively charged on its exterior than in its interior. propagating an action potential. experiencing depolarization.

polarized.

Which of the following muscles is named for its shape? vastus medialis levator scapulae triceps brachii pronator quadratus

pronator quadratus

The main immediate source of ATP (lasting about 10 seconds) as muscle contractions begin comes from: fat. creatine phosphate. glucose. glycogen.

reatine phosphate.

Which of the following is NOT one of the functions of skeletal muscle? generation of facial expressions voluntary control over defecation and urination thermoregulation regulation of the diameter of blood vessels and control of blood pressure

regulation of the diameter of blood vessels and control of blood pressure

The Na+/K+ pump helps a muscle cell maintain a state of: depolarization. resting membrane potential. action potential. propagation.

resting membrane potential.

The plasma membrane of a muscle cell is known as the: myofibril. sarcoplasmic reticulum. sarcomere. sarcolemma.

sarcolemma.

What is the functional contractile unit of the myofibril? sarcomere sarcolemma I band A band

sarcomere

What part of the myofibril shortens to produce contractions of the muscle fiber? myosin filaments A band elastic filaments sarcomere

sarcomere

The storage and release of calcium ions is the key function of the: sarcoplasmic reticulum. sarcolemma. sarcoplasm. mitochondrion.

sarcoplasmic reticulum.

Type I fibers lack: myoglobin. mitochondria. a blood supply. speed.

speed.

In a muscle, __________. the origin usually moves toward the insertion the origin is inferior to the insertion the origin that elevates a structure is generally located above that structure the insertion is usually the anchoring point

the origin that elevates a structure is generally located above that structure

Which of the following statements is the most accurate description of the sliding filament mechanism? Z discs slide over the thick and thin filaments both thick and thin filaments shorten thin filaments slide past thick filaments towards the M line. thick filaments shorten while thin filaments remain unchanged

thin filaments slide past thick filaments towards the M line.

The type of contraction represented by a single stimulus/contraction/relaxation sequence is a(n)__________. wave summation fused tetanus unfused tetanus twitch

twitch

During the repolarization stage of a muscle action potential__________. voltage-gated potassium ion channels open and potassium ions leave the cell voltage-gated sodium ion channels open and sodium ions enter the cell voltage-gated potassium ion channels open and potassium ions enter the cell voltage-gated sodium ion channels open and sodium ions leave the cell

voltage-gated potassium ion channels open and potassium ions leave the cell

What characteristic is NOT descriptive of cardiac muscle tissue? located in the heart voluntary muscle contractions striations intercalated discs

voluntary muscle contractions