CH10 HW - BIO151

Which portion of this myogram shows a single twitch of the muscle?

A

All of the muscle fibers within the muscle are fully contracted and are in sustained contraction with no individual twitches detected due to high frequency of stimulation.

D

In the diagram, where would you find stored Ca2+?

F

________ released from the sarcoplasmic reticulum bind to troponin to trigger exposure of binding sites on actin and begin the contraction cycle. ______ supplies energy to detach the myosin head from actin. a. Calcium ions; ATP b. Calcium ions; Titin c. Sodium ions; ATP d. Sodium ions; GTP

a. Calcium ions; ATP

A runner nearing the end of a marathon race would produce most ATP by: a. aerobic respiration. b. anaerobic respiration. c. creatine phosphate. d. amino acid breakdown.

a. aerobic respiration.

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

a. epimysium

After the fusion of myoblasts, the muscle fiber loses its ability to a. go through mitosis b. grow c. contract d. lengthen

a. go through mitosis

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

a. neuromuscular junction

Creatine phosphate reserves are restored via phosphorylation by ATP during rest. a. true b. false

a. true

Energy can be transferred in the muscle cell through the conversion of ATP into ADP. a. true b. false

a. true

In motor unit recruitment, the number of active motor units increases. a. true b. false

a. true

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 is correct

b. Elasticity

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. The drug will cause a weak contraction. b. The drug will increase contraction. c. The drug will cause spasm. d. The drug will prevent contraction.

b. The drug will increase contraction.

Which ATP production would be sufficient to run in place for one minute? a. creatine phosphate b. anaerobic cellular respiration c. aerobic cellular respiration

b. anaerobic cellular respiration

Contraction of myofibrils within a muscle fiber begins when a. an action potential travels t-tubules b. calcium is released from the sarcoplasmic reticulum c. acetylcholine binds to ligand gates d. calcium is moved into the sarcoplasmic reticulum e. sodium enters the muscle fiber

b. calcium is released from the sarcoplasmic reticulum

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

b. extensibility

Which term describes a somatic motor neuron and all the skeletal muscle fibers it stimulates? a. synapse b. motor unit c. motor end plate d. neuromuscular junction

b. motor unit

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. endomysium b. perimysium c. hypodermis d. epimysium e. fascia

b. perimysium

Mitochondrial activity in skeletal muscle cells are usually efficient, but can have limited ATP production if a. CO2 is produced as a waste product. b. there is limited O2 availability c. there is pyruvic acid accumulation.

b. there is limited O2 availability

Through aerobic respiration in the mitochondria, one glucose molecule can create a. 2 ATP b. 4 ATP c. 30 or more ATP d. None of these

c. 30 or more ATP

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. myofibrils c. acetylcholine d. intercalated discs e. creatine phosphate

c. acetylcholine

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. an incomplete twitch c. fused (complete) tentanus d. incomplete tetanus e. an extended muscle spasm

c. fused (complete) tentanus

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

c. myosin

. Skeletal muscle contraction is triggered to begin when calcium is released from a. mitochondria b. myofibrils c. terminal cisterns of sarcoplasmic reticulum d. T-tubules

c. terminal cisterns of sarcoplasmic reticulum

Muscle fibers produce ATP using: a. creatine phosphate. b. anaerobic cellular respiration. c. aerobic cellular respiration. d. all of the choices are correct

d. all of the choices are correct

Which protein does Calcium bind to? a. tropomyosin b. actin c. myosin d. troponin

d. troponin

What energizes the myosin head? a. acetylcholine b. ADP synthesis c. calcium ions d. Phosphate release e. ATP hydrolysis reaction

e. ATP hydrolysis reaction

The general functions of muscle tissue include: a. production of body movement. b. stabilization of body positions. c. storage and movement of substances through the body. d. heat generation. e. all of the choices are correct.

e. all of the choices are correct.

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

e. axon of neuron, sarcolemma, T tubules

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. glycogen b. creatine c. titin d. creatine phosphate e. myoglobin

e. myoglobin

Cross bridges are formed during muscle contraction when _____ binds to _____. a. actin; tropomyosin b. actin; myosin c. actin; troponin d. myosin; troponin e. myosin; actin

e. myosin; actin

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

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

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

e. smooth muscle and cardiac muscle

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. wave summation. b. fused tetanus c. unfused tetanus. d. refractory period. e. twitch contraction.

e. twitch contraction.

Which structure is the contractile organelle that contains the thick and thin filaments?

muscle fiber (cell)