A&P Exam 3 Chap. 9-10

Which of the following is correctly paired? a.)Skeletal muscle: voluntary control b.)Cardiac muscle: nonstriated c.)Smooth muscle: striated d.)Cardiac muscle: voluntary control

Which muscle characteristic describes the ability of muscle to respond to a stimulus? a.)contractility b.)extensibility c.)elasticity d.)excitability

One of the important functions of skeletal muscle contraction is production of heat.

Excitation-contraction coupling is a series of events that occur after the events of the neuromuscular junction have transpired. The term excitation refers to which step in the process? a.)Excitation refers to the release of calcium ions from the sarcoplasmic reticulum. b.)Excitation, in this case, refers to the propagation of action potentials along the sarcolemma. c.)Excitation refers to the propagation of action potentials along the axon of a motor neuron. d.)Excitation refers to the shape change that occurs in voltage-sensitive proteins in the sarcolemma.

Excitation of the sarcolemma is coupled or linked to the contraction of a skeletal muscle fiber. What specific event initiates the contraction? a.)Calcium release from the sarcoplasmic reticulum initiates the contraction. b.)Action potentials propagate into the interior of the skeletal muscle fiber. c.)Voltage-sensitive proteins change shape. d.)Sodium release from the sarcoplasmic reticulum initiates the contraction.

A triad is composed of a T-tubule and two adjacent terminal cisternae of the sarcoplasmic reticulum. How are these components connected? a.)Voltage-gated sodium channels. b.)Potassium leak channels. c.)Myosin cross-bridge binding sites. d.)A series of proteins that control calcium release.

What is name given to the regularly spaced infoldings of the sarcolemma? a.)transverse or T tubules b.)sarcoplasmic reticulum c.)terminal cisternae d.)motor endplates

Which of the following is most directly responsible for the coupling of excitation to contraction of skeletal muscle fibers? a.)Sodium ions. b.)Acetylcholine. c.)Action potentials. d.)Calcium ions.

What is the relationship between the number of motor neurons recruited and the number of skeletal muscle fibers innervated? a.)Motor neurons always innervate thousands of skeletal muscle fibers. b.)Typically, hundreds of skeletal muscle fibers are innervated by a single motor neuron. c.)A motor neuron typically innervates only one skeletal muscle fiber. d.)A skeletal muscle fiber is innervated by multiple motor neurons.

The cross bridge cycle is a series of molecular events that occur after excitation of the sarcolemma. What is a cross bridge? a.)ATP bound to a myosin head b.)Calcium bound to troponin c.)A myosin head bound to actin d.)Troponin bound to tropomyosin

What structure is the functional unit of contraction in a skeletal muscle fiber? a.)The sarcomere b.)The cross bridge c.)The triad d.)The junctional folds of the sarcolemma

Calcium ions couple excitation of a skeletal muscle fiber to contraction of the fiber. Where are calcium ions stored within the fiber? a.)Calcium ions are stored in the sarcoplasmic reticulum. b.)Calcium ions are stored in the mitochondria. c.)Calcium ions are stored in the nuclei. d.)Calcium ions are stored in the transverse tubules.

After a power stroke, the myosin head must detach from actin before another power stroke can occur. What causes cross bridge detachment? a.)ATP binds to the myosin head. b.)ADP and inorganic phosphate are bound to the myosin head. c.)Calcium ions bind to troponin. d.)Acetylcholine binds to receptors in the junctional folds of the sarcolemma.

How does the myosin head obtain the energy required for activation? a.)The energy comes from oxidative phophorylation. b.)The energy comes from the direct phosphorylation of ADP by creatine phosphate. c.)The energy comes from the hydrolysis of GTP. d.)The energy comes from the hydrolysis of ATP.

What specific event triggers the uncovering of the myosin binding site on actin? a.)Calcium ions bind to troponin and change its shape. b.)Calcium ions bind to tropomyosin and change its shape. c.)Sodium ions bind to troponin and change its shape. d.)Calcium release channels open in the sarcoplasmic reticulum, and calcium levels rise in the sarcoplasm.

When does cross bridge cycling end? a.)Cross bridge cycling ends when ATP binds to the myosin head. b.)Cross bridge cycling ends when sufficient calcium has been actively transported back into the sarcoplasmic reticulum to allow calcium to unbind from troponin. c.)Cross bridge cycling ends when calcium release channels in the sarcoplasmic reticulum open. d.)Cross bridge cycling ends when calcium ions are passively transported back into the sarcoplasmic reticulum.

What causes the release of calcium from the terminal cisternae of the sarcoplasmic reticulum within a muscle cell? a.)troponin b.)calcium ion pump c.)arrival of an action potential d.)ATP

The binding of calcium to which molecule causes the myosin binding sites to be exposed? a.)troponin b.)tropomyosin c.)actin d.)myosin

A myosin head binds to which molecule to form a cross bridge? a.)troponin b.)tropomyosin c.)actin

What causes the myosin head to disconnect from actin? a.)binding of troponin b.)hydrolysis of ATP c.)binding of calcium d.)binding of ATP

What causes the power stroke? a.)hydrolysis of ATP b.)release of ADP and Pi c.)calcium d.)binding of ATP

In a neuromuscular junction, synaptic vesicles in the motor neuron contain which neurotransmitter? a.)norepinephrine b.)dopamine c.)acetylcholine (ACh) d.)serotonin

When an action potential arrives at the axon terminal of a motor neuron, which ion channels open? a.)voltage-gated calcium channels b.)chemically gated calcium channels c.)voltage-gated sodium channels d.)voltage-gated potassium channels

What means of membrane transport is used to release the neurotransmitter into the synaptic cleft? a.)a channel b.)exocytosis c.)a protein carrier

The binding of the neurotransmitter to receptors on the motor end plate causes which of the following to occur? a.)Binding causes voltage-gated sodium channels to open in the motor endplate. b.)Binding causes potassium voltage-gated channels to open in the motor endplate. c.)Binding of the neurotransmitter causes chemically gated sodium channels to open in the motor end plate. d.)Binding causes chemically gated potassium channels to open in the motor end plate.

How is acetylcholine (ACh) removed from the synaptic cleft? a.)diffusion away from the synaptic cleft b.)a reuptake pump on the axon terminal c.)acetylcholinesterase (AChE; an enzyme)

The action potential on the muscle cell leads to contraction due to the release of calcium ions. Where are calcium ions stored in the muscle cell? a.)terminal cisternae of the sarcoplasmic reticulum b.)sarcolemma c.)cytosol d.)T tubule

What is the role of calcium in the cross bridge cycle? a.)Calcium binds to active sites on actin, forming the cross bridge. b.)Calcium binds to troponin, altering its shape. c.)Calcium binds to troponin, exposing the active site on troponin. d.)Calcium binds to myosin, causing the myosin head to release from the actin myofilament.

What role does tropomyosin play in the cross bridge cycle? a.)The displacement of tropomyosin exposes the active sites of actin, allowing cross bridges to form. b.)Tropomyosin binds to calcium, causing muscle relaxation. c.)Tropomyosin moves the actin filament relative to the myosin filament. d.)Tropomyosin pushes the myosin head away, causing cross bridge detachment.

How does troponin facilitate cross bridge formation? a.)Troponin gathers excess calcium that might otherwise block actin's progress. b.)Troponin controls the position of tropomyosin on the thin filament, enabling myosin heads to bind to the active sites on actin. c.)Troponin hydrolyzes ATP, which provides the energy necessary for cross bridges to form. d.)Troponin moves away from the active sites on actin, permitting cross bridge formation.

What, specifically, is a cross bridge? a.)ATP binding to the myosin head b.)calcium binding to troponin c.)tropomyosin covering the active sites on actin d.)myosin binding to actin

Which event causes cross bridge detachment? a.)release of ADP and inorganic phosphate from the myosin head b.)release of calcium from troponin c.)nervous input ends d.)ATP binding to the myosin head

Where in the cross bridge cycle does ATP hydrolysis occur? a.)during the movement of tropomyosin to expose the active sites on actin b.)during the power stroke c.)during the removal of calcium from troponin d.)during the cocking of the myosin head

How/when does the myosin head cock back to store energy for the next cycle? a.)when ADP is released from the myosin head b.)The sliding of the actin myofilament during the power stroke re-cocks myosin heads that have previously delivered their power stroke. c.)After the myosin head detaches, energy from ATP hydrolysis is used to re-cock the myosin head. d.)The power stroke cocks the myosin head.

BMD (2,3-butanedione 2-monoximime) inhibits myosin, such that ATP can bind to myosin but myosin is unable to hydrolyze the bound ATP. What effect would BMD have on the cross bridge cycle? a.)Tropomyosin would not move, and the active sites on actin would not be exposed. b.)Myosin heads would remain attached to actin, unable to perform the power stroke. c.)Myosin heads would remain attached to actin, unable to detach. d.)Myosin heads would remain detached, unable to cock.

During contraction, what prevents actin myofilaments from sliding backward when a myosin head releases? a.)Calcium blocks the active sites on actin. b.)There are always some myosin heads attached to the actin myofilament when other myosin heads are detaching. c.)The actin myofilament can only move in one direction relative to the myosin filament. d.)The cross bridge remains in place, preventing the actin myofilament from sliding.

Most skeletal muscles contain ________. a.)a predominance of fast oxidative fibers b.)muscle fibers of the same type c.)a predominance of slow oxidative fibers d.)a mixture of fiber types

The strongest muscle contractions are normally achieved by ________. a.)recruiting small and medium muscle fibers b.)increasing stimulus above the treppe stimulus c.)increasing the stimulation up to the maximal stimulus d.)increasing stimulus above the threshold

Myoglobin ________. a.)is a protein involved in the direct phosphorylation of ADP b.)breaks down glycogen c.)stores oxygen in muscle cells d.)produces the end plate potential

What structure in skeletal muscle cells functions in calcium storage? a.)sarcoplasmic reticulum b.)intermediate filament network c.)mitochondria d.)myofibrillar network

What does oxygen deficit represent? a.)the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used b.)amount of energy needed for exertion c.)the amount of oxygen taken into the body prior to the exertion d.)the amount of oxygen taken into the body immediately after the exertion

Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the ________ period during which the events of excitation-contraction coupling occur. a.)refractory b.)relaxation c.)latent d.)contraction

Creatine phosphate functions in the muscle cell by ________. a.)forming a temporary chemical compound with myosin b.)forming a chemical compound with actin c.)inducing a conformational change in the myofilaments d.)storing energy that will be transferred to ADP to resynthesize ATP

What controls the force of muscle contraction? a.)multimotor unit summation b.)wave summation c.)treppe d.)concentric contractions

The major function of the sarcoplasmic reticulum in muscle contraction is to ________. a.)synthesize actin and myosin myofilaments b.)provide a source of myosin for the contraction process c.)regulate intracellular calcium concentration d.)make and store phosphocreatine

What produces the striations of a skeletal muscle cell? a.)the sarcoplasmic reticulum b.)the arrangement of myofilaments c.)a difference in the thickness of the sarcolemma d.)the T tubules

Which of the following are composed of myosin? a.)thick filaments b.)Z discs c.)thin filaments d.)all myofilaments

During muscle contraction, myosin cross bridges attach to which active sites? a.)Z discs b.)thick filaments c.)actin filaments d.)myosin filaments

Rigor mortis occurs because ________. a.)proteins are beginning to break down, thus preventing a flow of calcium ions b.)sodium ions leak out of the muscle c.)the cells are dead b.)no ATP is available to release attached actin and myosin molecules

The oxygen-binding protein found in muscle cells is ________. a.)hemoglobin b.)myoglobin c.)immunoglobin d.)ATP

What is the functional unit of a skeletal muscle called? a.)a myofilament b.)a myofibril c.)a sarcomere d.)the sarcoplasmic reticulum

What is the role of calcium ions in muscle contraction? a.)form hydroxyapatite crystals b.)increase levels of myoglobin c.)reestablish glycogen stores d.)bind to regulatory sites on troponin to remove contraction inhibition

The warm-up period required of athletes in order to bring their muscles to peak performance is called ________. a.)incomplete tetanus b.)wave summation c.)treppe d.)twitch

The main effect of the warm-up period of athletes, as the muscle contractions increase in strength, is to ________. a.)enhance the availability of calcium and the efficiency of enzyme systems b.)increase the myoglobin content c.)tone the muscles and stabilize the joints for the workout d.)convert glycogen to glucose

During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to ________. a.)hydrochloric acid b.)lactic acid c.)a strong base d.)stearic acid

When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods? a.)fatigue period b.)latent period c.)refractory period d.)relaxation period

In an isotonic contraction, the muscle ________. a.)never converts pyruvate to lactate b.)does not change in length but increases tension c.)rapidly resynthesizes creatine phosphate and ATP d.)changes in length and moves the "load"

The muscle cell membrane is called the ________. a.)endomysium b.)sarcolemma c.)epimysium d.)perimysium

Which of the following is the correct sequence of events for muscle contractions? a.)motor neuron action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke, sliding of myofilaments b.)muscle cell action potential, neurotransmitter release, ATP-driven power stroke, calcium ion release from SR, sliding of myofilaments c.)neurotransmitter release, muscle cell action potential, motor neuron action potential, release of calcium ions from SR, sliding of myofilaments, ATP-driven power stroke d.)neurotransmitter release, motor neuron action potential, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke

Which of the following statements is true? a.)Striated muscle cells are long and cylindrical with many nuclei. b.)Smooth muscle cells have T tubules. c.)Cardiac muscle cells have many nuclei. d.)Cardiac muscle cells are found in the heart and large blood vessels.

An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is ________. a.)glycolysis b.)the electron transport chain c.)hydrolysis d.)the citric acid cycle

Muscle tone is ________. a.)a state of sustained partial contraction b.)the condition of athletes after intensive training c.)the ability of a muscle to efficiently cause skeletal movements d.)the feeling of well-being following exercise

After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction? a.)calcium ions returning to the terminal cistern b.)the action potential stops going down the overloaded T tubules c.)the tropomyosin blocking the myosin once full contraction is achieved d.)acetylcholinesterase destroying the ACh

Three discrete types of muscle fibers are identified on the basis of their size, speed, and endurance. Which of the following athletic endeavors best represents the use of red fibers? a.)boxing b.)a long, relaxing swim c.)playing baseball or basketball d.)a sprint by an Olympic runner

Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overlapped, ________. a.)no muscle tension could be generated b.)maximum force production would result because the muscle has a maximum range of travel c.)cross bridge attachment would be optimum because of all the free binding sites on actin d.)ATP consumption would increase because the sarcomere is "trying" to contract

What part of the sarcolemma contains acetylcholine receptors? a.)end of the muscle fiber b.)part adjacent to another muscle cell c.)any part of the sarcolemma d.)motor end plate

The time in which cross bridges are active is called the period of ________.

A smooth, sustained contraction is called ________.

Once a motor neuron has fired, all the muscle fibers in a muscle contract.

The force of muscle contraction is controlled by multiple motor unit summation or recruitment.

During isotonic contraction, the heavier the load, the faster the velocity of contraction.

A patient has no peristalsis in the gastrointestinal tract. Why would this be problematic? a.)The patient would be unable to expel his or her stool, leading to intestinal obstruction. b.)There would be no complications if a patient had no peristalsis. c.)The patient would be unable to swallow food, leading to malnutrition. d.)The patient would be unable to absorb the nutrients in the intestines, leading to malnutrition.

Which of the following is true about smooth muscle contraction? a.)Smooth muscle, in contrast to skeletal muscle, cannot synthesize or secrete any connective tissue elements. b.)Smooth muscle has well-developed T tubules at the site of invagination. c.)Certain smooth muscle cells can actually divide to increase their numbers. d.)Smooth muscle cannot stretch as much as skeletal muscle.

Peristalsis is characteristic of smooth muscle.

Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments.

Smooth muscles are able to regenerate throughout life.

When a geriatric patient is admitted to the rehabilitation unit, an important nursing measure is to prevent the loss of muscle mass. What is the term used for loss of muscle mass, and how can the patient prevent it? a.)Sarcopenia, where there is an increase in the amount of connective tissue and a decrease in the number of muscle fibers. This is irreversible. b.)Myasthenia gravis, where generalized muscle weakness occur. This can be reversed by weight-bearing exercise, unless atrophy is complete. c.)Disuse atrophy, where fibrous connective tissue replaces the muscle tissue that was lost. This can be prevented by regular weight-bearing exercise, unless atrophy is complete. d.)Myotonic dystrophy, where there is a gradual loss in muscle mass and in control of the muscles. This is irreversible.

The nurse encourages the patient to do his own activities of daily living such as bathing, eating, dressing, and toileting activities. How do these activities promote physical conditioning? a.)The contraction of the muscles in these activities reverses myotonic dystrophy and rebuilds muscle mass. b.)It does not. Only weight-bearing exercises maintain the shape, size and strength of muscles. c.)The contraction of the muscles in these activities helps maintain the shape, size, and strength of muscles, as well as joint mobility. d.)The contraction of the muscles in these activities reverses sarcopenia and rebuilds muscle mass.

Which muscle cells have the greatest ability to regenerate? a.)smooth b.)no muscle can regenerate c.)cardiac d.)skeletal

__________ are muscles that serve as the primary promoters of a movement. a.)Antagonists b.)Fixators c.)Synergists d.)Agonists

Which class of muscle has the major responsibility for a specific movement? a.)fixator b.)agonist c.)synergist d.)antagonist

When the term biceps, triceps, or quadriceps forms part of a muscle's name, what does it tell you about the muscle? a.)The muscle has two, three, or four origins, respectively. b.)The muscle is able to change direction twice, three times, or four times faster than other muscles, respectively. c.)The muscle has two, three, or four functions, respectively. d.)The muscle has two, three, or four insertions, respectively.

A muscle group that works with and assists the action of a prime mover is a(n) ________. a.)fixator b.)synergist c.)antagonist d.)protagonist

Which generalization concerning movement by skeletal muscles is not true? a.)During contraction the two articulating bones move equally. b.)The movements produced may be of graded intensity. c.)The bones serve as levers. d.)Muscles produce movement by pulling on bones.

Which of the following is not used as a criterion for naming muscles? a.)The locations of muscle attachments b.)Whether the muscle is controlled by the involuntary or voluntary nervous system c.)The number of origins for the muscle d.)The shape of the muscle e.)The location of the muscle

Choose the false statement. a.)The hamstring crosses the knee joint. b.)Hamstrings promote knee rotation. c.)The hamstrings are fleshy muscles of the posterior thigh. d.)The hamstring crosses the hip joint.

Which of the following muscles is named for its origin and insertion? a.)trapezius b.)deltoid c.)sternocleidomastoid d.)gluteus maximus

What are the muscles that are found at openings of the body collectively called? a.)convergent muscles b.)parallel muscles c.)divergent muscles d.)circular muscles

Which of these is not a way of classifying muscles? a.)the type of muscle fibers b.)muscle location c.)muscle shape d.)the type of action they cause

Muscles are only able to pull, they never push.

Muscles that help to maintain posture are often called synergists.

Which of the following is correctly matched? a.)Convergent arrangement of fascicles: fan shaped muscle b.)Parallel arrangement of fascicles: characteristic of sphincter muscles c.)Circular arrangement of fascicles: describes the deltoid muscle d.)Pennate arrangement of fascicles: spindle shaped muscle

Most skeletal muscles of the body act as: a.)third-class levers. b.)power levers. c.)second-class levers. d.)first-class levers.

Which of the following movements demonstrates a first-class lever? a.)lifting a rock with your right hand and arm b.)lifting weights with your legs c.)standing on your toes d.)raising your head up off your chest

Which type of lever is demonstrated by using scissors? a.)a first-class lever b.)a second-class lever c.)a third-class lever d.)a fourth-class lever

What is the major factor controlling how levers work? a.)the direction the load is being moved b.)the weight of the load c.)the difference in the positioning of the effort, load, and fulcrum d.)the structural characteristics of the muscles of the person using the lever

Which of the following describes fascicle arrangement in a pennate muscle? a.)The fascicles are in a fusiform arrangement. b.)The fascicular pattern is circular. c.)The fascicles form a triangle. d.)The fascicles are short and attach obliquely to a central tendon that runs the length of a muscle.

What is the main factor that determines the power of a muscle? a.)the shape b.)the number of neurons innervating it c.)the length d.)the total number of muscle cells available for contraction

If a lever operates at a mechanical disadvantage, it means that the ________. a.)load is near the fulcrum and the effort is at the distal end b.)lever system is useless c.)load is far from the fulcrum and the effort is applied near the fulcrum d.)effort is farther than the load from the fulcrum

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

In a pennate muscle pattern ________. a.)there is a narrow origin diverging to a broad insertion b.)muscles look like a feather c.)there is a broad origin and fascicles converge toward a single tendon d.)muscles appear to be straplike

What are the levers that operate at a mechanical advantage called? a.)speed levers b.)dysfunctional levers c.)functional levers d.)power levers

First-class levers ________. a.)have load at one end of the lever, fulcrum at the other, and effort applied somewhere in the middle b.)are the type found in the joints forming the ball of the foot as used in raising the body on the toes c.)in the body can operate at a mechanical advantage or mechanical disadvantage, depending on specific location d.)are typified by tweezers or forceps

If L = load, F = fulcrum, and E = effort, what type of lever system is described as LEF? a.)first-class lever b.)fourth-class lever c.)third-class lever d.)second-class lever

Both first- and second-class levers operate at a mechanical disadvantage.

Although all skeletal muscles have different shapes, the fascicle arrangement of each muscle is exactly the same.

Regardless of type, all levers follow the same basic principle: effort farther than load from fulcrum = mechanical advantage; effort nearer than load to fulcrum = mechanical disadvantage.