Chapter 9 A&P

Which muscle(s) can contract without the need for nervous stimulation? Skeletal muscle only Smooth muscle only Cardiac muscle only Smooth and cardiac muscle Skeletal, smooth, and cardiac muscle

Smooth and cardiac muscle

Smooth muscle and cardiac muscle are similar in that they both are striated. have multiple nuclei. are under involuntary control. are under voluntary control. are widely distributed in the body.

are under involuntary control.

Smooth muscle and cardiac muscle are similar in that they both have multiple nuclei. are under involuntary control. are striated. are widely distributed in the body. are under voluntary control.

are under involuntary control.

During resting conditions, _________ is synthesized to store energy. creatinine Ca2+ pyruvate lactate creatine phosphate

creatine phosphate

Rigor mortis occurs after death because cross-bridges never form. myosin levels decline at death. anaerobic respiration is occurring. Ca2+ is actively transported back to the sarcoplasmic reticulum. cross-bridges form but can't release.

cross-bridges form but can't release.

Complete tetanus is the condition in which the muscle fiber only partially relaxes between contractions. is the condition in which stimuli occur so rapidly that there are no intervening relaxations. is the constant tension produced by muscles for long periods of time. is the time during which the tissue cannot respond again. results in complete and incomplete tetanus.

is the condition in which stimuli occur so rapidly that there are no intervening relaxations.

Muscle hypertrophy results from increased numbers of myofibrils and sarcomeres. muscle cells. muscle fibers. motor units. muscles.

myofibrils and sarcomeres.

The sites where a chemical substance is transmitted from the presynaptic terminal of an axon to the postsynaptic membrane of a muscle fiber are called cell bodies of neurons. neuromuscular junctions. myofilaments. Z disks. sarcomeres.

neuromuscular junctions.

Skeletal muscle fibers do not require nerve innervation to contract. increase dramatically in number after birth. are found in the walls of the stomach. can contract but are not extensible or excitable. possess striations.

possess striations.

A myofilament is the plasma membrane of a muscle fiber cytoplasm of a muscle fiber protein strand composed of actin or myosin structural and functional unit of the skeletal muscle fiber contractile thread that extends the length of the muscle fiber.

protein strand composed of actin or myosin

Muscles exhibit the property of excitability. This means that the muscle shortens its length. stretches beyond its normal length. responds to stimulation by the nervous system. excites itself. recoils to its original resting length.

responds to stimulation by the nervous system.

T tubules are invaginations of the sarcomere. myofibril. sarcoplasmic reticulum. sarcoplasm. sarcolemma.

sarcolemma.

Maureen is hiking in the cold, and to maintain homeostasis her body begins to release chemicals to initiate a high fever. increase heat loss from the skin. reduce her blood pressure. vasodilate vessels in her head and neck. shiver.

shiver

The model that describes the contraction of the muscle is called the paddle model. power stroke. sliding filament model. contraction cycle. slipping fibril mechanism.

sliding filament model.

A sarcomere is the plasma membrane of a muscle fiber. contractile thread that extends the length of the muscle fiber. cytoplasm of a muscle fiber. structural and functional unit of the skeletal muscle fiber. protein strand composed of actin or myosin.

structural and functional unit of the skeletal muscle fiber.

Epimysium connects muscles to bone. is a type of muscle tissue. separates muscle fibers. surrounds individual muscles. is a type of nerve tissue.

surrounds individual muscles.

When skeletal muscle is producing CO2 and water while making ATP, which chemical processes could be active at this time? Anaerobic respiration Aerobic respiration Both anaerobic respiration and aerobic respiration are correct.

Aerobic respiration

What is an oxygen deficit? The movement of myosin head while attached to actin myofilament After exercise, the O2 taken in that exceeds the O2 required for resting metabolism The combination of myosin heads with active sites on actin molecules A T tubule and two adjacent terminal cisternae A protein found along the groove of the F-actin double helix

After exercise, the O2 taken in that exceeds the O2 required for resting metabolism

You are hired to work in a laboratory to measure the rate of human muscle contraction. Which of the following might decrease in quantity in muscle fibers undergoing contractions? ATP Water Lactate Carbon dioxide Na+

ATP

Randy is participating in a strong man competition and is required to pull a yacht as far as he can. Which type of chemical process will his skeletal muscles rely on during this competition? Aerobic respiration Anaerobic respiration Both anaerobic respiration and aerobic respiration are correct.

Anaerobic respiration

Which type of muscle tissue causes contraction of the heart? Skeletal muscle Smooth muscle Cardiac muscle

Cardiac muscle

Which of the following is NOT a function of skeletal muscle? Constriction of organs Production of heat Body movement Maintenance of posture Respiration

Constriction of organs

Which of the following conditions in muscle fibers would contribute to muscle fatigue? Blocked receptors in the postsynaptic membrane Depletion of neurotransmitter Inability of the motor neuron to produce sufficient quantities of acetylcholine The emotional state of an individual Depletion of ATP reserves

Depletion of ATP reserves

Which of the following connective tissue layers is outside all the others? Endomysium Perimysium Epimysium Paramysium Sarcolemma

Epimysium

Identify the statement concerning skeletal muscle that is true. It is responsible for locomotion. Its function is largely under involuntary control. It propels urine through the urinary tract. It is a kind of connective tissue. It comprises about 20% of the body's weight.

It is responsible for locomotion.

Which of the following actions is caused by contraction of skeletal muscle? Contraction of the heart Vasoconstriction Moving your feet in walking Emptying of the urinary bladder Movement of food through the digestive tract

Moving your feet in walking

Identify the statement concerning general functional characteristics of muscle that is true. None of these statements are true. Muscle tissue shortens forcefully but lengthens passively. Muscle tissue can get shorter, but cannot get longer. Muscle tissue shortens passively but lengthens forcefully. Muscle tissue can get longer, but cannot get shorter.

Muscle tissue shortens forcefully but lengthens passively.

Which of the following is true? Overstretching a muscle will increase its tension. Optimal actin and myosin overlap will produce maximal contraction. The greater the overlap of actin and myosin, the stronger the contraction. The greatest amount of tension is achieved when actin and myosin do not overlap. Tension is great when actin and myosin overlap as much as they can.

Optimal actin and myosin overlap will produce maximal contraction.

Which type of muscle tissue has neuromuscular junctions? Skeletal muscle Smooth muscle Cardiac muscle

Skeletal muscle

Which type of muscle tissue is multinucleated? Skeletal muscle Cardiac muscle Both skeletal and cardiac muscle are correct. Both cardiac and smooth muscle are correct. Smooth muscle

Skeletal muscle

Which type of muscle tissue would cause flexion and extension of the arm? Skeletal muscle Cardiac muscle Smooth muscle

Skeletal muscle

What is a cross-bridge? After exercise, the O2 taken in that exceeds the O2 required for resting metabolism A protein found along the groove of the F-actin double helix A T tubule and two adjacent terminal cisternae The combination of myosin heads with active sites on actin molecules The movement of myosin head while attached to actin myofilament

The combination of myosin heads with active sites on actin molecules

What is the power stroke? After exercise, the O2 taken in that exceeds the O2 required for resting metabolism A protein found along the groove of the F-actin double helix A T tubule and two adjacent terminal cisternae The movement of myosin head while attached to actin myofilament The combination of myosin heads with active sites on actin molecules

The movement of myosin head while attached to actin myofilament

Which of the following is true concerning isotonic concentric contraction? The muscle lengthens, and tension declines. The muscle shortens, but tension remains constant. The muscle tenses, but length remains unchanged. The muscle lengthens, but tension remains constant. The muscle tenses and shortens.

The muscle shortens, but tension remains constant.

Which of the following is composed of myosin molecules? Thick myofilaments I bands Sarcolemma Tropomyosin Z disks

Thick myofilaments

An isometric contraction is described as a muscle produces constant tension during contraction. action potential frequency is high enough that no relaxation of muscle fibers occurs. a muscle produces an increasing tension as the length remains constant. a muscle produces increasing tension as it shortens. a muscle produces tension, but the length of the muscle is increasing.

a muscle produces an increasing tension as the length remains constant.

An isotonic contraction is described as a muscle produces an increasing tension during contraction. a muscle produces constant tension during contraction. action potential frequency is high enough that no relaxation of muscle fibers occurs. a muscle produces increasing tension as it shortens. a muscle produces tension, but the length of the muscle is increasing.

a muscle produces constant tension during contraction.

As muscle activity increases, the body temperature __________. increases decreases

increases

If one nerve stimulus arrives at a muscle fiber so soon that the fiber does NOT relax at all from the previous twitch, the most likely result will be __________. fatigue wave summation incomplete tetanus complete tetanus spasm

complete tetanus

T tubules store calcium ions. release acetylcholine. generate new muscle fibers. conduct action potentials deep into the muscle fiber. provide nutrients to the muscle fiber.

conduct action potentials deep into the muscle fiber.

Muscle myofibrils are found in the sarcolemma. do not appear striated. hold muscle fibers together. contain myosin and actin myofilaments. extend from the sarcolemma to the T-tubule.

contain myosin and actin myofilaments.

The capacity of a muscle cell to shorten forcefully is known as extensibility. excitability. flexibility. elasticity. contractility.

contractility.

Cardiac muscle cells are like skeletal muscle cells in that they both have striations. are multinucleated. lack sarcomeres. possess intercalated disks. depolarize as a result of Na+ and Ca2+ influxes.

have striations.

Tetanus of a muscle is thought to be caused by the rapid movement of Na+ back into the sarcoplasmic reticulum. increased temperature in the active muscle. high Ca2+ concentrations in the sarcoplasm. decreased amounts of Ca2+ in muscle tissue. an increase in stimulus strength.

high Ca2+ concentrations in the sarcoplasm.

Anabolic steroids can do all of the following except increase muscle size and strength. increase total muscle mass. cause cardiovascular disease. increase the number of muscle fibers. cause testicular atrophy.

increase the number of muscle fibers.

Incomplete tetanus is the time during which the tissue cannot respond again. is the condition in which stimuli occur so rapidly that there are no intervening relaxations. results in complete and incomplete tetanus. is the constant tension produced by muscles for long periods of time. is the condition in which the muscle fiber only partially relaxes between contractions.

is the condition in which the muscle fiber only partially relaxes between contractions.

The time between application of the stimulus to a motor neuron and the beginning of contraction is called the __________ phase. contraction latent or lag refractory threshold relaxation

latent or lag

A sustained muscle contraction is known as __________. tone paralysis treppe twitch tetanus

tetanus

Oxygen deficit represents the amount of CO2 that cells need to eliminate. the amount of O2 that cells need to replenish ATP supplies after exercise. the amount of O2 converted to lactate during exercise. the amount anaerobic metabolism must increase after exercise. conversion of pyruvate to lactate.

the amount of O2 that cells need to replenish ATP supplies after exercise.

The type of muscle fatigue known as "psychological fatigue" is the result of None of these choices are correct. decreased levels of acetylcholine. depleted ATP reserves. the emotional state of an individual. increased Ca2+ concentration in the sarcoplasm.

the emotional state of an individual.

Increased strength of a trained muscle is due to the nervous system's ability to recruit a large number of motor units simultaneously. an increased number of muscle fibers. elimination of unnecessary connective tissue. elimination of all adipose tissue. elimination of unnecessary enzymes and metabolic pathways.

the nervous system's ability to recruit a large number of motor units simultaneously.

Myosin is also known as the thin myofilament. short myofilament. intermediate myofilament. sarcomere. thick myofilament.

thick myofilament.

A muscle fiber will respond to a stimulus when that stimulus reaches the __________ level. threshold resting rigor mortis relaxation recruitment

threshold