Unit 3

Which portion of this myogram shows a single twitch of the muscle? A B C D none of these choices

A

For crossbridges to occur, what events must happen? Select all that apply. A. ATPase breaks down ATP B. Acetylcholinesterase be present in the synaptic cleft C. Calcium ions be present in the sarcoplasm D. High amounts of sodium be present in the synaptic cleft E. Myosin binding sites be exposed

A. ATPase breaks down ATP C. Calcium ions be present in the sarcoplasm E. Myosin binding sites be exposed

Which ATP production would be sufficient to run in place for one minute? A. Anaerobic cellular respiration B. Aerobic cellular respiration C. Creatine phosphate

A. Anaerobic cellular respiration

For the muscle to contract and relax, what must be present? Select all that apply. A. Calcium ions B. cAMP C. ATP D. ACh E. Chloride ions

A. Calcium ions C. ATP

Myofibrils contain what type of proteins? Select all that apply. A. Contractile proteins. B. Regulatory proteins. C. Tensile proteins D. Structural proteins. E. All choices are correct

A. Contractile proteins. B. Regulatory proteins. D. Structural proteins.

Which regions of the sarcomere contain thick filaments? Select all that apply. A. H zone B. I band C. A band D. Zone of overlap E. Z discs

A. H zone C. A band D. Zone of overlap

During muscle contractions, thin filaments are pulled towards the A. M line. B. Z disc. C. I band. D. A band. E. H zone.

A. M line.

Which functions as a motor protein in all three types of muscle tissue? A. Myosin B. Tropomyosin C. Actin D. Troponin E. Titin

A. Myosin

The medication Thapsigarginis acts as a potent calcium ATPase pump inhibitor. What state of the myogram would be affected immediately? A. Relaxation period B. Latent period C. Contraction period D. None of the myogram stages are affected

A. Relaxation period

When an athlete performs a pull up (raising their chin to a bar while their body hangs), the process of pulling the body up so the chin can touch the bar is A. concentric. B. eccentric. C. isometric.

A. concentric.

World class atheletes known as "power lifters" will have a higher percentage of ________ in their arm muscles. A. fast glycolytic fibers B. fast oxidative fibers C. slow oxidative fibers

A. fast glycolytic fibers

Strength training would result in A. hypertrophy of fast oxidative-glycolytic and fast glycolytic fibers. B. atrophy of fast oxidative-glycolytic fibers. C. conversion of slow oxidative fibers to fast oxidative-glycolytic fibers. D. hypertrophy of slow oxidative fibers.

A. hypertrophy of fast oxidative-glycolytic and fast glycolytic fibers.

Motor unit recruitment occurs when there is a(n) ________ in the number of active motor units within a skeletal muscle. A. increase B. decrease C. no change

A. increase

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

A. rapid destruction of ACh in the synaptic cleft by acetylcholinesterase.

Skeletal muscle contraction is triggered to begin when calcium is released from A. terminal cisterns of sarcoplasmic reticulum. B. mitochondria. C. transverse-tubules. D. myofibrils. E. synaptic end bulbs

A. terminal cisterns of sarcoplasmic reticulum.

Which type of muscle tissue contracts when excited by their own autorhythmic muscle fibers? A. Slow twitch oxidative skeletal muscle B. Cardiac muscle C. Multi-unit smooth muscle D. Fast twitch glycolytic skeletal muscle E. None of the above

B. Cardiac muscle

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

B. E

Which of the following is a function specific to smooth and cardiac muscle tissue? A. Stabilizing the movement of joints B. Moving and storing material throughout the body C. Promoting movement of body structures D. Generating heat through contractions E. All choices are specific to smooth and cardiac muscle tissue

B. Moving and storing material throughout the body

The zone of overlap increases during the A. relaxation period. B. contraction period. C. absolute refractory period. D. latent period. E. relative refractory period.

B. contraction period.

When an athlete performs a pull up (raising their chin to a bar while their body hangs), the process of lowering the body down is A. concentric. B. eccentric. C. isometric.

B. eccentric.

After the fusion of myoblasts, the muscle fiber loses its ability to A. lengthen. B. go through mitosis. C. grow. D. contract. E. All answers are correct

B. go through mitosis.

What energizes the myosin head? A. Calcium ions B. Acetylcholine C. ATP hydrolysis reaction D. Phosphate release E. ADP synthesis

C. ATP hydrolysis reaction

Which protein is used to reinforce the sarcolemma and help transmit the tension generated by the sarcomeres to the tendons? A. Actin B. Myosin C. Dystrophin D. Tropomyosin E. Troponin

C. Dystrophin

Which property of muscle gives it the ability to stretch without damage? A. Elasticity B. Contractility C. Extensibility D. Electrical excitability E. None of the answers are correct

C. Extensibility

Which microscopic structure is found only in the cardiac muscle tissue? A. Striations B. Myosin C. Intercalated discs D. Sarcomeres E. Tropomyosin

C. Intercalated discs

The medication Diltiazemis acts as a calcium channel blocker, reducing free intracellular calcium. What stage of the myogram would be affected immediately? A. Contraction period B. Relaxation period C. Latent period D. All myogram stages are affected

C. Latent period

Which term describes a somatic motor neuron and all the skeletal muscle fibers it stimulates? A. Synapse B. Motor end plate C. Motor unit D. Neuromuscular junction

C. Motor unit

Which type of muscle tissue is capable of undergoing the stress-relaxation response when stretched? A. Fast glycolytic fibers B. Multiunit smooth muscle fibers C. Single-unit smooth muscle fibers D. Fast oxidative-glycolytic fibers E. Cardiac muscle fibers

C. Single-unit smooth muscle fibers

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. refractory period. B. fused tetanus. C. twitch contraction. D. unfused tetanus. E. wave summation.

C. twitch contraction.

All of the muscle fibers within the muscle are fully contracted in A B C D

D

Which correctly lists the sequence of structures that action potentials must move through to excite skeletal muscle contraction? A. Muscle fiber, axon of neuron, myofibrils B. Sarcolemma, axon of neuron, T tubules C. Myofibrils, myofilaments, mitochondria D. Axon of neuron, sarcolemma, T tubules E. . T tubules, sarcolemma, myofilament

D. Axon of neuron, sarcolemma, T tubules

Which region of a sarcomere contain thin filaments? A. A band B. I band C. H zone D. Both I band and A band. E. None of the above answers are correct

D. Both I band and A band.

Why will and individual who lifts weights build larger muscles? A. Skeletal muscles signal satellite cells to increase number of cells B. Skeletal muscle myofibrils and cells increase in number C. Skeletal muscles are hyperplastic and respond to stress D. Skeletal muscles increase number of myofibrils but not number of cells

D. Skeletal muscles increase number of myofibrils but not number of cells

What is the direct result of acetylcholine attaching to the ligand gated channels of the motor end plate? A. Calcium ions will be actively transported into the SR B. Calcium voltage gates on the neurolemma are inactive C. The positive charge of the sarcolemma decreases D. The sarcolemma increases permeability to sodium ions E. The sarcolemma decreases permeability to sodium ions

D. The sarcolemma increases permeability to sodium ions

Why would cardiac muscles have longer refractory periods than skeletal muscles? A. The muscle types contain different contractile proteins B. Skeletal muscle is autorhythmic C. Skeletal muscles have prolonged calcium influx D. To preserve the normal rhythm of the heart and prevent fatigue E. Cardiac muscle is not dependent on aerobic respiration to produce ATP

D. To preserve the normal rhythm of the heart and prevent fatigue

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 (lactate) produced during exercise back into pyruvic acid (pyruvate). B. replace oxygen displaced from muscle myoglobin. C. resynthesize creatine phosphate. D. all of these choices are correct E. only A and B are correct

D. all of these choices are correct

Smooth muscle tone is maintained by the prolonged presence of ________ in the muscle cell's cytosol? A. ATP B. sodium ions C. acetylcholine D. calcium ions E. oxygen

D. calcium ions

In skeletal muscles, the combined amounts of creatine phosphate and stored ATP provide enough energy for the muscle to contract maximally for approximately A. 2-3 minutes. B. 15-20 minutes. C. 3-5 seconds. D. one minute. E. 15 -20 seconds.

E. 15 -20 seconds.

The opening of ligand gates on the sarcolemma is directly caused by A. acetylcholinesterase activity. B. acetylcholine attachment. C. calcium influx into the motor neuron. D. sodium influx into the muscle fiber. E. All choices are correct.

E. All choices are correct.

Which of the regions of a sarcomere contain titin? A. The zone of overlap only B. The A band only C. The I band only D. The H zone only E. From M line to Z disc

E. From M line to Z disc

Which characteristics describe both skeletal and cardiac muscle? A. Somatic control B. Cell shape C. Autonomic control D. Autorhymicity E. Striations

E. Striations

Contraction of sarcomeres within a muscle fiber specifically begins when A. sodium enters the muscle fiber. B. an muscle action potential travels t-tubules. C. calcium is moved back into the sarcoplasmic reticulum. D. acetylcholine binds to ligand gated Na+ channels. E. calcium is released from the sarcoplasmic reticulum and binds troponin.

E. calcium is released from the sarcoplasmic reticulum and binds troponin.

The outermost layer of connective tissue surrounding a skeletal muscle is the A. ligament. B. endomysium. C. perimysium. D. tendon. E. epimysium.

E. epimysium.

Cross bridges are formed during muscle contraction when ________ binds to ________. A. actin; myosin B. myosin; troponin C. actin; troponin D. actin; tropomyosin E. myosin; actin

E. myosin; actin

In the diagram, where would you find stored Ca2+? F G K B D

F

In the diagram, what area contains both thick and thin filaments? H I G Both B and C

H