Chapters 10 and 20

5) In an isometric contraction the muscle develops tension but does not a) lengthen. b) widen. c) does not expend energy. d) conduct electrical current. e) exhibit elasticity.

A

24) To stimulate skeletal muscle contraction, acetylcholine must cross the _____ of the neuromuscular junction and bind to receptors on the motor endplate. a) node of Ranvier b) synaptic cleft c) sarcolemma d) synaptic end bulb e) transverse tubule

B

28) Which of the following consists of a somatic motor neuron and all the skeletal muscle fibers it stimulates? a) sarcomere b) motor unit c) neuromuscular junction d) muscle unit e) multi-unit smooth muscle

B

10) The contractile organelles of a skeletal muscle fiber are thread-like structures called a) myofibrils. b) myoglobin. c) mitochondria. d) Z discs. e) M lines.

a

12) What type of tissue comprises the valves of the heart? a) Dense connective tissue b) Areolar connective tissue c) Hyaline cartilage d) Cardiac muscle tissue e) Adipose tissue

a

2) The membrane that surrounds and protects the heart is called the a) pericardium. b) pleura. c) myocardium. d) mediastinum. e) endocardium.

a

21) Calcium ions are released from the sarcoplasmic reticulum into the cytosol a) at the beginning of a contraction. b) in response to acetylcholine binding to Ca2+ release channels. c) by active transport using Ca2+ pumps in the SR membrane. d) after the contraction ends. e) All of these answers are correct.

a

21) Which of the following blood vessel is used to distribute oxygenated blood to the myocardium? a) Coronary artery b) Coronary vein c) Coronary sinus d) Vena cava e) Myocardial vein

a

26) In skeletal muscles, the combined amounts of creatine phosphate and ATP provide enough energy for the muscle to contract maximally for approximately a) 15 seconds. b) 15 minutes. c) 1.5 minutes. d) 5 seconds. e) one minute.

a

28) The volume of blood ejected from the left ventricle into the aorta each minute is called the a) cardiac output. b) cardiac input. c) stroke volume. d) heart rate. e) pulse pressure.

a

30) Which of the following is referred to as the period of lost excitability in skeletal muscle fibers? a) refractory period b) contraction period c) latent period d) relaxation period e) wave summation

a

30) Which of the following is referred to as the period of lost excitability in skeletal muscle fibers? a) refractory period b) contraction period c) latent period57) What is being shown by the axis labeled E? d) relaxation period e) wave summation

a

32) This is the least powerful type of skeletal muscle fiber. a) slow oxidative fiber b) fast oxidative fiber c) fast glycolytic fiber d) slow glycolytic fiber e) None of these choices.

a

34) Which of the following types of muscle tissue contract when excited by their own autorhythmic muscle fibers?

a

34) Which of the following types of muscle tissue contract when excited by their own autorhythmic muscle fibers? a) cardiac muscle b) slow twitch oxidative skeletal muscle c) multi-unit smooth muscle d) fast twitch glycolytic skeletal muscle e) All of these choices are correct.

a

61) Which figure exhibits concentric contraction of the biceps brachii muscle? a) A b) B c) C d) none of these choices

a

71) During which period of a twitch contraction does the muscle action potential move along the sarcolemma of the muscle cell and trigger calcium release into the sarcoplasm? a) latent period b) contraction period c) relaxation period d) absolute refractory period e) relative refractory period

a

12) Which of the following describe the regeneration capacity of cardiac muscle cells? a) limited, via satellite cells b) limited, under certain conditions c) considerable (compared with other muscle cells, but limited compared with epithelium), via pericytes d) all of these are correct e) none of these are correct

b

17) What regulatory proteins can be found in the thin filaments of skeletal muscle fibers? a) troponin and titin b) tropomyosin and troponin c) myosin and titin d) titin and tropomyosin e) tropomyosin and myosin

b

23) Skeletal muscle contraction will continue to occur as long as the following chemicals are available in the cytosol of the muscle fiber. a) ATP and acetylcholine (ACh) b) calcium ions and ATP c) ACh and potassium ions d) sodium ions and ATP e) calcium and ACh

b

27) In comparison to skeletal muscle fibers, the contractile fibers of the heart are depolarized for _____ period of time. a) a shorter b) a longer c) the same

b

36) Which wave in an electrocardiogram represents repolarization of the ventricles? a) R wave b) T wave c) S wave d) P wave e) Q wave

b

55) Which of the following disorders is characterized by the wasting away of muscles due to the progressive loss of myofibrils? a) muscular hypertrophy b) muscular atrophy c) fibromyalgia d) myasthenia gravis e) tremors

b

73) In comparison to a sedentary individual, a well-trained athlete will usually have all the following characteristics EXCEPT a) a higher cardiac reserve. b) a higher resting cardiac output. c) a higher stroke volume. d) hypertrophy of the heart. e) resting bradycardia.

b

Which figure exhibits a contraction of the biceps brachii muscle in which its length increases? a) A b) B c) C d) none of these choices

b

11) Release of calcium from these structures triggers skeletal muscle contraction. a) myofibrils b) mitochondria c) terminal cisterns of sarcoplasmic reticulum d) T-tubules e) none of the answer choices

c

20) During muscle contraction by the sliding filament mechanism, thin filaments are pulled towards the a) Z disc. b) H zone. c) M line. d) A band. e) I band.

c

22) Cardiac muscle fibers are electrically connected to neighboring fibers by a) desmosomes. b) tight junctions. c) gap junctions. d) interneurons. e) chordae tendinae.

c

23) Which of the following type of muscle contains the largest number of mitochondria per cell? a) Smooth muscle b) Skeletal muscle c) Cardiac muscle d) All the muscle types contain approximately the same number. e) Mitochondria are not found in muscle cells.

c

29) A brief contraction of all muscle fibers in a motor unit in response to a single action potential moving down the somatic motor neuron is known as a) isometric contraction. b) isotonic contraction. c) tetany. d) refractory period. e) twitch contraction.

c

3) Which of the following is NOT a major function of muscle tissue? a) moving blood throughout the body b) generating heat through contractions c) stabilizing the movement of joints d) promoting movement of body structures e) production of vitamins.

c

31) Increasing the number of active motor units within a skeletal muscle is called a) wave summation. b) fused tetanus. c) motor unit recruitment. d) muscle tone. e) flaccidity.

c

57) What is being shown by the axis labeled E? a) time b) tetanus c) force of contraction d) twitch factor e) wave summation

c

58) Which area of the myogram shows sustained contraction with partial relaxation? a) A b) B c) C d) D e) none of these choices

c

60) Which figure exhibits isometric contraction of the biceps brachii muscle? a) A b) B c) C d) none of these choices

c

64) Which of the following types of abnormal contractions of skeletal muscle may be caused by holding a position for a prolonged period? a) spasm b) fasciculation c) tremor d) fibrillation e) cramp

c

68) Which of the following types of muscle tissue is capable of undergoing the stress-relaxation response when they are stretched? a) cardiac muscle fibers b) fast glycolytic fibers c) fast oxidative-glycolytic fibers d) slow oxidative fibers e) single-unit smooth muscle fibers

c

69). Cross bridges are formed during muscle contraction when _____ on the thick filaments binds to _____ on the thin filaments. a) myosin; troponin b) myosin; troponin c) myosin; actin d) actin; myosin e) actin; tropomyosin

c

7) Which layer of the heart wall consists of cardiac muscle tissue? a) Epicardium b) Pericardium c) Myocardium d) Endocardium e) Hypocardium

c

72) Which of following is a common characteristic of fast glycolytic (FG) skeletal muscle fibers? a) large amount of myoglobin. b) many mitochondria. c) low concentration of creatine kinase in the sarcoplasm. d) slow myosin ATPase. e) high amount of glycogen in the sarcoplasm.

c

73) Myasthenia Gravis is an autoimmune disorder that targets the ACh receptors at the NMJ and ultimately reduces the number of available receptors. Predict what happens if you treat the patient with a drug that inhibits the activity of acetylcholinesterase? a) prevent contraction b) weak contraction c) normal contraction d) cause spasm e) none of these choices

c

During which period of a twitch contraction does the muscle action potential move along the sarcolemma of the muscle cell and trigger calcium release into the sarcoplasm? a) latent period b) contraction period c) relaxation period d) absolute refractory period e) relative refractory period

c

Which of the following types of muscle tissue is capable of undergoing the stress-relaxation response when they are stretched? a) cardiac muscle fibers b) fast glycolytic fibers c) fast oxidative-glycolytic fibers d) slow oxidative fibers e) single-unit smooth muscle fibers

c

29) A brief contraction of all muscle fibers in a motor unit in response to a single action potential moving down the somatic motor neuron is known as a) isometric contraction. b) isotonic contraction. c) tetany. d) refractory period. e) twitch contraction

c57) What is being shown by the axis labeled E?

25) Which network of specialized cardiac muscle fibers provide a path for each cycle of cardiac excitation to progress through the heart? a) Systemic circuit b) Intercalated discs c) Cardiovascular center d) Cardiac conduction system e) Pulmonary circuit

d

25) Which of the following are commonly used to produce ATP during skeletal muscle contraction? a) creatine phosphate b) anaerobic cellular respiration c) aerobic cellular respiration d) All of these choices are correct. e) None of these choices are correct.

d

26) Which of the following correctly lists the sequence of structures that a cardiac action potential follows in order to excite normal contraction of the heart? a) Bundle of His, Purkinje fibers, Atrioventricular (AV) node b) Sinoatrial (SA) node, Purkinje fibers, AV node, Bundle of His c) Purkinje fibers, AV node, SA node, Bundle of His d) SA node, AV node, Bundle of His, Purkinje fibers e) Bundle of His, SA node, AV node, Purkinje fibers

d

29) Which term refers to the period of time during a cardiac cycle when contraction of a chamber occurs and pressure within the chamber rises? a) filling b) systole c) repolarization d) diastole e) fibrillation

d

32) Which structure in the heart initiates action potentials that stimulate contraction of the heart at constant rate of about 100 beats per minute? a) Cardiac accelerator nerves b) Atrioventricular node c) Cardiovascular center d) Sinoatrial node e) Bundle of His

d

33) Stimulation of which nerve reduces heart rate? a) Cardiac accelerator nerve b) Hypoglossal nerve c) Spinal accessory d) Vagus nerve e) Phrenic nerve

d

33) Which of the following microscopic structures is only found in the cardiac muscle tissue? a) myosin b) tropomyosin c) sarcomeres d) intercalated discs e) striations

d

38) Which of the following electrocardiogram (EKG) waves represents atrial depolarization? a) R wave b) T wave c) S wave d) P wave e) Q wave

d

5) Which of the following is used to reduce friction between the layers of membranes surrounding the heart? a) Synovial fluid b) Endocardium c) Pleural fluid d) Pericardial fluid e) Capillary endothelium

d

59) Which area of the myogram shows a sustained contraction where individual twitches are indiscernible? a) A b) B c) C d) D e) none of these choices

d

6) This is the outermost layer of connective tissue surrounding a skeletal muscle. a) tendon b) ligament c) endomysium d) epimysium e) perimysium

d

66) Which of the following statements does NOT accurately describe aerobic cellular respiration in skeletal muscles? a) Pyruvic acid generated by glycolysis enters the mitochondria. b) O2 is essential. c) CO2 is produced as a waste product. d) Lactic acid is continually produced. e) Can be used to generate ATP from fats, proteins or carbohydrates.

d

9) Which of the following correctly lists the sequence of structures that action potentials must move through to excite skeletal muscle contraction? a) sarcolemma, axon of neuron, T tubules b) T tubules, sarcolemma, myofilament c) muscle fiber, axon of neuron, myofibrils d) axon of neuron, sarcolemma, T tubules e) myofibrils, myofilaments, mitochondria

d

70) Isovolumetric contraction is the phase of the cardiac cardiac cycle in which a) the semilunar valves are open. b) ventricular repolarization occurs. c) atrial depolarization occurs. d) oxygenated blood leaves the heart into the systemic circulation. e) ventricular pressure increases and ventricular volume remains the same.

e