Anatomy & Physiology, Chapter 10

e) twitch contraction.

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.

d) This pathway is aerobic

A skeletal muscle fiber can produce ATP in a variety of ways (metabolic pathways), however one method produces enough ATP to support physical activity for many hours. Which statement below is correct about this pathway? a) This is the pathway that produces lactic acid. b) This is the pathway that uses creatine phosphate to convert ADP to ATP. c) This pathway is anaerobic. d) This pathway is aerobic e) This is the pathway that produces lactic acid and is anaerobic.

c) muscle tone

A small amount of muscle tension and muscle definition (the appearance of muscle beneath the skin) is present even in a relaxed muscle. A person who is physically fit due to regular exercise, will have more of this characteristic of muscle tissue than someone who is not fit. What is this characteristic? a) muscle contraction b) muscle refraction c) muscle tone d) muscle refraction e) muscle recruitment

d) All of these choices

After prolonged strenuous exercise has stopped, heavy breathing will often continue for several minutes in order to provide the oxygen needed to a) convert the lactic acid produced during exercise back into glycogen. b) resynthesize creatine phosphate.c) replace oxygen displaced from muscle myoglobin. d) All of these choices e) None of these choices

d) go through cell division.

After the fusion of myoblasts, the muscle fiber loses its ability to do what? a) grow b) lengthen c) contract d) go through cell division. e) all of the answer choices

d) Stage 4

At which stage of the contraction cycle (see diagram) do the myosin heads bind ATP, causing the crossbridges to detach from the actin filament? a) Stage 1 b) Stage 2 c) Stage 3 d) Stage 4 e) that stage is not shown

c) H zone

Choose the region that will narrow or disappear during muscle contraction? Consult the image for assistance. a) Z disc b) M line c) H zone d) A band e) thick filament

c) myosin; actin

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

e) smooth muscle cells have the greatest ability to regenerate

Depending on how specialized a type of muscle tissue is, the muscle fibers or cells of that tissue will have varied abilities to regenerate (healing and production of new cells). What type of muscle tissue has the greatest ability to regenerate? a) skeletal, cardiac and smooth muscle all have similar abilities to regenerate b) only skeletal and cardiac muscle cells can undergo limited regeneration c) only cardiac and smooth muscle cells can undergo regeneration d) although all muscle cells can undergo some regeneration, only skeletal muscle fibers can do it easily and frequently, especially when we regularly exercise e) smooth muscle cells have the greatest ability to regenerate

c) M line.

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.

d) myosin heads reorient and reenergize

During the contraction cycle ATP is hydrolyzed (cleaved) to form ADP + P. Which process is fueled by the energy released by this reaction? a) myosin-binding-sites are revealed b) powerstrokes occur c) crossbridges form d) myosin heads reorient and reenergize e) crossbridges break

c) myosin

During the contraction cycle, ATP attaches to a) actin b) troponin c) myosin d) tropomyosin e) none of these choices

a) latent period

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) slow oxidative fibers

If you are an endurance athlete, you especially rely on which type of skeletal muscle fiber to perform your sport? a) slow oxidative fibers b) fast oxidative-glycolytic fibers c) fast glycolytic fibers d) all of these choices are correct. e) none of these choices are correct.

c) rapid destruction of ACh in the synaptic cleft by acetylcholinesterase.

In a neuromuscular junction, the effect of acetylcholine (ACh) binding to receptors on the motor end plate lasts only briefly due to a) rapid uptake of the ACh into the myofiber. b) endocytosis of the ACh receptor into the myofiber. c) rapid destruction of ACh in the synaptic cleft by acetylcholinesterase. d) rapid destruction of ACh in the synaptic cleft by monoamine oxidase. e) diffusion of the ACh out of the synaptic cleft.

a) 15 seconds.

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) C, D, and H

In the diagram, a tendon is formed by the merging of the following structures a) C, D, and H b) D and E c) H and C d) C and D e) All of these choices are correct.

c) L

In the diagram, individual muscle fibers are covered by this layer. a) K b) I c) L d) M e) A

a) B

In the diagram, the neurotransmitter, acetylcholine, is released from this area. a) B b) C c) D d) G e) H

c) F

In the diagram, what is the basic functional unit of a myofibril? a) B b) C c) F d) Both B and C e) All of these choices are correct.

b) E

In the diagram, where are thick filaments found? a) C b) E c) A d) B e) All of these choices

a) G

In the diagram, where is the I band? a) G b) H c) I d) J e) D

a) A

In the diagram, where is the axon terminal? a) A b) B c) C d) D e) E

d) F

In the diagram, where would you find stored Ca2+? a) B b) D c) G d) F e) K

c) E

In the diagram, which structure helps return a stretched sarcomere to its resting length? a) B b) C c) E d) Both B and C e) All of these choices are correct.

a) A

In the diagram, which structure(s) moves towards the center of the sarcomere (closer together) when the fiber contracts? a) A b) D c) J d) Both A and D. e) None of these are correct.

d) muscle fiber.

In the drawing, the circle is indicating a: a) somatic motor neuron. b) filament. c) myofibril. d) muscle fiber. e) myofibril fascicle.

c) motor unit recruitment.

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) fast oxidative-glycolytic

Leg muscles are predominantly composed of which type of muscle fiber? a) slow oxidative b) fast glycolytic c) fast oxidative-glycolytic d) slow glycolytic e) fast oxidative

e) 50%

Most people don't notice they've lost muscle strength until around age 60 - 65. By this time, what percentage of muscle mass has the average person lost? a) 10% b) 20% c) 30% d) 40% e) 50%

b) Elasticity

Muscular tissue has several important properties, such as electrical excitability. Another property of muscular tissue is that it is able to stretch, and return to its original size and shape. Which property of muscular tissue is this? a) Conductivity b) Elasticity c) Extensibility d) Plasticity e) None of these are correct.

c) normal contraction

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

b) activation of ACh receptors

Native people of the Amazon basin in South America use curare, a poison, on arrows and blow darts, to paralyze and bring down small game. Which part of the sequence of events at the neuromuscular junction does curare specifically disrupt? a) release of acetylcholine (ACh) b) activation of ACh receptors c) production of a muscle action potential d) activation of acetylcholinesterase e) release of calcium from the terminal cisterns

b) B

On the diagram, where is the outer most layer of connective tissue encircling the entire muscle a) A b) B c) C d) D e) E

c) terminal cisterns of sarcoplasmic reticulum

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

d) perimysium

Skeletal muscle is covered, surrounded and protected by various layers of connective tissue. Which layer of connective tissue would surround a bundle of muscle fibers (muscle cells)? a) epimysium b) hypodermis c) fascia d) perimysium e) endomysium

c) smooth muscle fibers contain thin and thick filaments, as well as intermediate filaments, but none of them are arranged in sarcomeres

Smooth muscle fibers do not have striations like skeletal and cardiac muscle cells do. This is because: a) the sarcomeres are smaller than in cardiac muscle cells and skeletal fibers, and aren't visible even when smooth muscle fibers are examined microscopically b) smooth muscle fibers contain only intermediate filaments, which aren't arranged in sarcomeres c) smooth muscle fibers contain thin and thick filaments, as well as intermediate filaments, but none of them are arranged in sarcomeres d) visceral smooth muscle fibers don't have striations, but multiunit smooth muscle cells do, but these cells are more rare, and so we rarely have a chance to view them with a microscope e) both b and d are correct

b) calcium ions

Smooth muscle tone is maintained by the prolonged presence of _____ in the muscle cell's cytosol? a) ATP b) calcium ions c) phosphate ions d) myoglobin e) None of these choices.

d) the myofibril

The contractile organelle of skeletal muscle fibers is a) the endoplasmic reticulum b) the myofilament c) the T tubule d) the myofibril e) the sarcomere

a) myofibrils.

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.

e) All of these choices are correct.

The different types of muscle tissue differ from each other by a) microscopic anatomy. b) location. c) type of Control. d) both microscopic anatomy and location. e) All of these choices are correct.

a) neuromuscular junction

The site where a somatic motor neuron releases acetylcholine to stimulate a skeletal muscle fiber is called the a) neuromuscular junction b) synaptic end bulbs c) motor end plate d) myofibril e) sarcolemma

a) slow oxidative fiber

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.

d) epimysium

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

c) intercalated discs

This structure is unique to cardiac muscle cells, and allows individual cells to be firmly attached to each other (to provide mechanical strength during contraction), and also allow the action potential to spread rapidly through the cardiac muscle tissue, so that contractions are smooth and coordinated. a) desmosomes b) gap junctions c) intercalated discs d) Z discs e) sarcomeres

b) synaptic cleft

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

True

True/False: Nearly all muscles of the body develop from an early embryonic layer of cells called the mesoderm.

False

True/False: Stretching is most effective at reducing injury and promoting greater flexibility if it is done over the course of many weeks, and always when the muscle is cold (before beginning to exercise).

True

True/False: To delay the onset of muscle fatigue, not all the motor units in a muscle will contract at the same time. Some will remain relaxed while others are contracting. If the contraction continues, and greater force is needed, more motor units will be recruited.

a) muscle rigidity that occurs approximately 3-24 hours after death, because ATP is no longer being produced

What is rigor mortis? a) muscle rigidity that occurs approximately 3-24 hours after death, because ATP is no longer being produced b) a condition in there are no acetylcholine receptors in the motor end plate of the muscle fiber c) a condition in which motor neurons cannot release acetylcholine d) a condition in which muscle tears can't be repaired, due to a lack of human growth hormone (hGH) e) an injury characterized by a stretched or torn tendon or muscle

b) tropomyosin and troponin

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

c) fast glycolytic fibers

What type of skeletal muscle fiber would an Olympic quality weight lifter specifically be developing during training, to enhance his or her weight lifting power? a) slow oxidative fibers b)fast oxidative-glycolytic fibers c) fast glycolytic fibers d) all of these choices e) none of these choices

d) aponeurosis

What type of tendon is formed when the connective tissue elements of a skeletal muscle extend as a broad flat layer? a) perimysium b) deep fascia c) fascicle d) aponeurosis e) endomysium

b) it diffuses into mitochondria to be broken down to generate ATP

When oxygen is plentiful inside a skeletal muscle cell, what happens to the pyruvic acid that is formed during glycolysis? a) it is converted into lactic acid b) it diffuses into mitochondria to be broken down to generate ATP c) it diffuses out of the cell and into the bloodstream d) it is used to convert creatine into creatine phosphate e) it is converted into glycogen

c) C

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

b) 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

a) A

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

c) C

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

d) deepening of the voice

Which is a NOT a side-effect of anabolic steroid use by male athletes? a) sterility b) baldness c) diminished testosterone secretion d) deepening of the voice e) atrophy of testes

c) c

Which letter is pointing to the phase of a muscle twitch where myosin heads are detaching, and calcium ions are being actively transported back into the sarcoplasmic reticulum? a) a b) b c) c d) this would be happening during letters b and c e) this would happen during letters a and b

e) both blood vessels, stomach, esophagus and bladder, uterus, small intestine

Which list of organs contains smooth muscle tissue? a) blood vessels, stomach, esophagus b) bladder, uterus, small intestine c) biceps brachii, triceps brachii (muscles of the arm) d) heart e) both blood vessels, stomach, esophagus and bladder, uterus, small intestine

e) high amount of glycogen in the sarcoplasm.

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.

d) All of these choices are correct.

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.

b) motor unit

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

d) axon of neuron, sarcolemma, T tubules

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

b) limited, under certain conditions

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) muscular atrophy

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) myosin

Which of the following functions as a motor protein in all three types of muscle tissue? a) actin b) myosin c) troponin d) titin e) tropomyosin

e) all of these are correct

Which of the following is a common effect of aging on skeletal muscle? a) loss of muscle mass b) decrease in maximal strength c) a slowing of muscle reflexes d) loss of flexibility e) all of these are correct

e) acetylcholine

Which of the following is directly responsible for transmitting an action potential from a motor neuron to a skeletal muscle fiber? a) gap junctions b) intercalated discs c) myofibrils d) creatine phosphate e) acetylcholine

d) moving food through the small intestine

Which of the following is not a function of skeletal muscle tissue? a) moving your eyes from left to right as you read this question b) holding your head up c) shivering to generate body heat when you've become chilled d) moving food through the small intestine e) stabilizing joints and helping to maintain body positions

b) When a muscle cell is contracting, it stores calcium ions.

Which of the following is not a function of the structure indicated in the image? a) It is similar to the smooth endoplasmic reticulum found in non-muscle cells. b) When a muscle cell is contracting, it stores calcium ions. c) It stores calcium ions in enlarged regions called terminal cisterns. d) This system of tubules surrounds each myofibril in a muscle cell. e) Along with T tubules, it forms triads within a muscle cell.

a) refractory period

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

d) intercalated discs

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

c) myoglobin

Which of the following molecules found in skeletal muscle cells binds oxygen that can later be used during aerobic metabolism to help generate ATP? a) creatine b) creatine phosphate c) myoglobin d) titin e) glycogen

e) only a and c would have many small motor units

Which of the following muscle groups would be more likely to have many small motor units (one motor neuron, and just a few muscle fibers under its control)? a) the muscles that control eye movement b) the postural muscles that control standing c) the muscles that control the many movements of the hands d) all of these choices would have many small motor units e) only a and c would have many small motor units

e) dystrophin

Which of the following proteins is used to reinforce the sarcolemma and to help transmit the tension generated by the sarcomeres to the tendons? a) troponin b) tropomyosin c) myosin d) actin e) dystrophin

d) Both I band and A band.

Which of the following regions of a sarcomere contain thin filaments? a) I band b) A band c) H zone d) Both I band and A band. e) All of these answer choices are correct.

e) All of these answer choices are correct

Which of the following regions of the sarcomere contain thick filaments? a) zone of overlap b) A band c) H zone d) both A band and H zone e) All of these answer choices are correct

e) some studies have shown it boosts athletic performance when taken as a supplement and some studies have shown no benefit to athletic performance when it is taken as a supplement

Which of the following statements about creatine are correct? a) some studies have shown it boosts athletic performance when taken as a supplement b) some studies have shown no benefit to athletic performance when it is taken as a supplement c) it is harmful, and will cause kidney damage d) all of these choices are correct e) some studies have shown it boosts athletic performance when taken as a supplement and some studies have shown no benefit to athletic performance when it is taken as a supplement

d) Lactic acid is continually produced.

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.

c) the person has added more thin and thick filaments to their muscles

Which of the following statements is correct about why a person's muscles get larger after weeks of regular exercise and strength training? a) the person has been able to change the proportion of skeletal muscle fiber types in the exercised muscles (i.e., they've added more slow oxidative fibers to their muscles) b) the person has stimulated some of their muscle fibers to reproduce—they have added additional cells to their exercised muscles c) the person has added more thin and thick filaments to their muscles d) all of these choices can happen with exercise e) none of these choices explain muscle enlargement

a) A

Which of the following structures are made of dense regular connective tissue? a) A b) F c) I d) Both F and I e) All of these choices.

e) cramp

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

a) cardiac muscle

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.

e) single-unit smooth muscle fibers

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

a) release of excessive amounts of acetylcholine at the neuromuscular junction

Which of the following would not be a contributing factor to muscle fatigue? a) release of excessive amounts of acetylcholine at the neuromuscular junction b) a feeling that you want to quit, that the activity is too difficult (central fatigue) c) depletion of adequate supplies of oxygen and ATP d) a buildup of lactic acid e) all of these contribute to muscle fatigue

b) B

Which of the labeled structures on the diagram holds muscles with similar functions together, allows free movement of muscles, carries nerves, blood vessels and lymphatic vessels, and fills spaces between muscles? a) A b) B c) E d) G e) H

d) from M line to Z disc

Which of the regions of a sarcomere contain titin? a) the A band only b) the H zone only c) the zone of overlap only d) from M line to Z disc e) the I band only

a) A

Which portion of this myogram shows a single twitch of the muscle? a) A b) B c) C d) D e) none of these choices

c) extensibility

Which property of muscle gives it the ability to stretch without damage? a) electrical excitability b) contractility c) extensibility d) elasticity e) thermogenesis

c) Z disc

Which structure occurs at the border between two adjacent sarcomeres? Consult the image for assistance. a) thin filament b) thick filament c) Z disc d) M line e) A band

e) b and c only

Which type of muscle tissue is involuntary (can't be consciously controlled)? a) skeletal muscle b) smooth muscle c) cardiac muscle d) a and b only e) b and c only

d) 1,2 &3

Why does skeletal muscle require more ATP than many other tissues in the body? 1 both contraction and relaxation require ATP to occur 2 the sarcoplasmic reticulum uses ATP to "pump" calcium ions back into the terminal cisterns after contraction 3 ATP is needed to convert creatine into creatine phosphate needed to provide energy at the beginning of muscle contraction a) 1 only b) 2 only c) 3 only d) 1,2 &3 e) Only 1 and 3

b) fused (complete) tentanus

[Refer to the diagram to help you with this question.] When a person is hooked up to a machine that will record myograms, a record of their muscle activity can be produced (depending on the frequency and strength of the stimuli that generate an action potential in their muscle tissue). If the person receives a series of multiple stimuli in a short period of time, the wave of muscle activity that will be recorded will show a sustained contraction with no period of relaxation in between the periods when they receive the stimuli. The myograms has recorded: a) a fused (complete) twitch b) fused (complete) tentanus c) an incomplete twitch d) incomplete tetanus e) an extended muscle spasm