Ch.11 Muscular tissue

Which of the following is true? Smooth muscle cells are long and cylindrical. Cardiac muscle cells have multiple nuclei. Skeletal muscle is capable of spontaneous contraction. Smooth muscle is found in the walls of hollow organs. There is a small amount of smooth muscle in the heart.

Smooth muscle is found in the walls of hollow organs.

38. Which structures are reservoirs that store acetylcholine? Synaptic vesicles Lysosomes Terminal cisternae Sarcomeres Synaptic clefts

Synaptic vesicles

The structure responsible for attaching muscle to bone is what?

Tendon

A deficiency of acetylcholine receptors leads to muscle paralysis in myasthenia gravis True False

True

An isometric contraction does not change muscle length. True False

True

Clinically, dystrophin is the most important noncontractile protein to occur in muscle fibers. True False

True

Extensibility refers to the ability of a muscle to stretch. True False

True

The connection between the nervous system and skeletal muscle allow for voluntary control of movement. True False

True

The sarcoplasmic reticulum is the smooth endoplasmic reticulum of a muscle fiber True False

True

Which letter is associated with the line that is a thin protein structure that serves as an attachment site for thin filament ends? H M A I Z

Z

The top long distance runners probably have _______ proportion of slow muscle fibers in their leg muscles. a lower the same a higher

a higher

Each thick filament contains about ______ protein molecules (each molecule has two heads and two braided tails). a)200 b)220 c)2 d)2000

a)200

Which are possible functions of skeletal muscles? a: Maintenance of posture b: Both highly coordinated and localized simple movements c: Temperature regulation d: Support of certain body organs e: Regulation of the movement of material through certain body tracts a, b, e a, b, c a, b, c, d, e a, b, c, d a, b, c, e

a, b, c, d, e

Glycolysis is an: aerobic process that occurs in the cytosol. anaerobic process that occurs in the mitochondria. anaerobic process that occurs in the cytosol. aerobic process that occurs in the mitochondria.

anaerobic process that occurs in the cytosol.

Fibers from one motor unit: are clustered together within one fascicle of the muscle. are dispersed throughout most of the muscle.

are dispersed throughout most of the muscle.

The type of muscle fibers that are striated, form Y-shaped branches, and have junctions called intercalated discs are: skeletal. voluntary. cardiac. smooth. skeletal and voluntary.

cardiac.

A drug that interferes with the active transport of calcium ions from the sarcoplasm back into the sarcoplasmic reticulum would result in an imbalance of blood calcium. fibrosis of the muscle. relaxation of the muscle fiber. contraction with no relaxation. muscle hypertrophy.

contraction with no relaxation.

When a muscle relaxes: crossbridges form and muscle extensibility returns the muscle to rest length. crossbridges stop forming and muscle elasticity returns the muscle to rest length. crossbridges stop forming and muscle extensibility returns the muscle to rest length crossbridges form and muscle elasticity returns the muscle to rest length.

crossbridges stop forming and muscle elasticity returns the muscle to rest length.

List the following structures in order from smallest to largest. (1) muscle fiber (2) myofilament (3) myofibril (4) muscle fasciculus a)2, 1, 4, 3 b)1, 2, 3, 4 c)3, 1, 4, 2 d)2, 3, 1, 4 e)4, 2, 3, 1

d)2, 3, 1, 4

Arrange the following list of biochemical events in the correct sequence. (1) An action potential is conducted deep into the muscle fiber by the T tubule. (2) Calcium ions bind to troponin. (3) The membranes of the sarcoplasmic reticulum become more permeable to calcium ions. (4) Calcium ions diffuse into the sarcoplasm around the myofibril. (5) The troponin-tropomyosin complex moves exposing active sites. a)1, 5, 2, 3, 4 b)1, 2, 3, 4, 5 c)1, 3, 2, 5, 4 d)1, 4, 3, 2, 5 e)1, 3, 4, 2, 5

e)1, 3, 4, 2, 5

Collagen is contractile. expendable. excitable. elastic. impermeable.

elastic.

The characteristic of muscle that allows it to be passively stretched is: contractility. elasticity. excitability. conductivity. extensibility.

extensibility.

39. The most prevalent of skeletal muscle fibers in the body are _____ fibers. slow fast intermediate

fast

Muscles of the eye and hand have a high percentage of _______ fibers. slow fast

fast

"Intermediate fibers" is another name for: fast, glycolytic fibers. slow, glycolytic fibers. fast, oxidative fibers. slow, oxidative fibers.

fast, oxidative fibers.

A motor unit within the powerful quadriceps muscle would: generally contain less than ten fibers. be much like those in the eye muscles. generally contain several hundred fibers. contain several motor neurons.

generally contain several hundred fibers.

The phosphagen system is used for: long term ATP needs and is dependent on oxygen. immediate ATP needs and is dependent on oxygen. long term ATP needs and is not dependent on the presence of oxygen. immediate ATP needs and is not dependent on oxygen.

immediate ATP needs and is not dependent on oxygen.

The training regimen of a competitive weight lifter is designed partly to lower the threshold for muscle excitation. convert certain parallel muscles into stronger pennate muscles. increase the size of his motor units. convert white muscle tissue to red muscle. increase the average number of myofibrils per muscle fiber.

increase the average number of myofibrils per muscle fiber.

Which of the following is NOT a known effect of illegal use of anabolic steroids in large dosages? kidney damage increased cardiovascular fitness diminished testosterone secretion sterility increased muscle size

increased cardiovascular fitness

Select the term that does not belong with the others. increased vascularity muscle atrophy decrease in number of myofibrils immobilization loss of nerve stimulation

increased vascularity

The contraction strength of smooth muscle is relatively independent of its resting length partly because it does not have sarcomeres. it is involuntary muscle. it is regulated by a length-tension relationship. it does not have intercalated discs. it gets nearly all of its Ca2+ from the extracellular fluid.

it does not have sarcomeres.

A volleyball player depends on the gastrocnemius muscles for plantar flexion, whereas a marathon runner depends more on the soleus muscles for the same action. This is because the soleus muscles don't have as many blood capillaries per gram of tissue. have smaller mitochondria. make more use of aerobic respiration. break ATP down to ADP and Pi faster. have more glycogen in them.

make more use of aerobic respiration.

A skeletal muscle cell contains hundreds to thousands of _________, which are complex organelles; they are cylindrical in shape--about 2 micrometers in diameter and as long as the cell. T-tubules sarcomeres microfilaments sarcolemma myofibrils

myofibrils

Which of the following is very important for muscle to continue contraction during anaerobic respiration? protease myokinase cholinesterase inhibitors acid phosphatase acetylcholinesterase

myokinase

Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate. These drugs prevent calcium from entering smooth muscle, thus allowing the muscle to relax. prevent calcium from entering cardiac muscle, thus slowing down the heart rate. stimulate the calcium pump in smooth muscle, thus removing calcium from the calmodulin. prevent calcium from entering the sarcoplasmic reticulum of smooth muscle. prevent calcium from exiting the sarcoplasmic reticulum in skeletal muscle.

prevent calcium from entering smooth muscle, thus allowing the muscle to relax.

As you are lifting a box, someone places extra weight on top of it. For your muscle to continue contracting and lifting the box, the muscle must lower its threshold. shift from isometric to isotonic contraction. recruit more muscle fibers. shift from slow-twitch to fast-twitch mode. reduce its wave summation.

recruit more muscle fibers.

The process of bringing more motor units into use during a muscle contraction is called incomplete tetanus. wave summation. complete tetanus. recruitment. treppe.

recruitment.

The latchbridge mechanism of myosin heads is a property of ________ muscle. cardiac skeletal smooth

smooth

Which muscle(s) can contract without the need for nervous stimulation? smooth and cardiac muscle skeletal muscle skeletal, smooth and cardiac muscle smooth muscle cardiac muscle

smooth and cardiac muscle

The absence or inhibition of acetylcholinesterase at a synapse would lead to which of the following? numbness flaccid paralysis tetanus atrophy muscle wasting

tetanus

The calcium ions involved in skeletal muscle contraction bind to a(n)______ subunit. elastin tropomyosin actin troponin myosin

troponin

Which fibers are primarily responsible for producing lactic acid? type I slow-twitch fibers red fibers type IIB fast glycolytic fibers type IIA intermediate glycolytic fibers type I slow oxidative fibers

type IIB fast glycolytic fibers

The repolarization of the action potential involves the opening of: chemically gated Na+ channels. chemically gated K+ channels. voltage-gated Na+ channels. voltage-gated K+ channels.

voltage-gated K+ channels.

Michael Jordan was arguably the best player in professional basketball history. Scientifically one would expect him to have highly developed intermediate fibers. slow oxidative fibers. fast-twitch fibers. red fibers. white fibers.

white fibers.

Creatine kinase 1.donates one of its phosphate groups to ADP 2.catalyzes the transfer of phosphate from CP to ADP. 3.phosphorylates and activates certain enzymes in the sarcoplasm. 4.functions as a substitute for ATP during anaerobic fermentation. 5.acts as a second messenger in muscle fibers.

2.catalyzes the transfer of phosphate from CP to ADP.

Which of the myofilaments of a muscle fiber has the active sites to which the heads of the thick filaments will bind? 1.Troponin 2.Sarcoplasm 3.Actin 4.Myosin 5.Tropomyosin

3.Actin

A child ingested an organophosphate poison used to kill insects. Soon the child's muscles began spastic contractions. Predict what occurred at the synaptic cleft. 1.decreased release of acetylcholine from presynaptic neurons 2.Both increased accumulation of acetylcholine in the synapse and increased breakdown of acetylcholine in the synaptic cleft. 3.increased accumulation of acetylcholine in the synapse 4.increased breakdown of acetylcholine in the synaptic cleft 5.the poison binds to acetylcholine receptors and stimulates them

3.increased accumulation of acetylcholine in the synapse

A typical skeletal muscle cell contains approximately _____ mitochondria. 30 300 3 3000

300

Aerobic respiration produces approximately _____ more ATPs per glucose molecule than glycolysis does. 36 48 24 100 12

36

In comparison to skeletal muscle, smooth muscle 1.contracts more slowly but relaxes more rapidly. 2.depends on a nerve fiber to supply the calcium needed for contraction. 3.consumes more ATP to maintain a given level of muscle tension. 4.contracts and relaxes more slowly. 5.contracts more rapidly but relaxes more slowly.

4.contracts and relaxes more slowly.

Where would you expect to find numerous gap junctions in muscular tissue? 1.multiunit smooth muscle 2.the A bands of skeletal and cardiac muscle 3.the sarcolemma of skeletal muscle 4.intercalated discs of cardiac muscle 5.the sarcoplasmic reticulum of skeletal muscle

4.intercalated discs of cardiac muscle

Which of the following structures contains the other four items listed? 1.receptors on postsynaptic membrane 2.synaptic cleft 3.ostsynaptic membrane 4.neuromuscular junction 5.presynaptic terminal

4.neuromuscular junction

The membranous network that wraps around myofibrils and holds relatively high concentrations of calcium is known as the: 1.sarcomere. 2.Golgi body. 3.sarcolemma. 4.sarcoplasmic reticulum. 5.T-tubule.

4.sarcoplasmic reticulum.

During muscle contraction, a single myosin head consumes ATP at a rate of about 7 ATP per second. 1 ATP per second. 3 ATP per second. 5 ATP per second. 9 ATP per second.

5 ATP per second.

Which are the reservoirs that store the calcium required for muscle contraction? 1.Mitochondria 2.Peroxisomes 3.Synaptic vesicles 4.Synaptic clefts 5.Terminal cisternae

5.Terminal cisternae

The contraction strength of smooth muscle is relatively independent of its resting length partly because 1.it does not have intercalated discs. 2.it is involuntary muscle. 3.it is regulated by a length-tension relationship. 4.it gets nearly all of its Ca2+ from the extracellular fluid. 5.it does not have sarcomeres.

5.it does not have sarcomeres.

In skeletal muscle, alternating light and dark bands are 1.termed 2.myoblasts. 3.treppe. 4.strabismus. 5.striations. 6.myofibrils.

5.striations.

The purpose of varicosities in motor nerve fibers in muscle physiology is 1.to enable each cardiac myocyte to directly stimulate its neighbors. 2.to reabsorb the decomposition products of acetylcholine after acetylcholinesterase breaks it down. 3.to prevent single-unit smooth muscle cells from pulling apart. 4.to link the thin filaments to the inside of the sarcolemma in smooth muscle. 5.to release neurotransmitter onto smooth muscle cells.

5.to release neurotransmitter onto smooth muscle cells.

Which of the following is true? Muscle fatigue has no influence on the force of contractions. A subthreshold stimulus causes a muscle contraction. Motor units do not obey the "all or none" law. A threshold stimulus will not affect motor units. A threshold stimulus will cause contraction of a muscle fiber.

A threshold stimulus will cause contraction of a muscle fiber.

ATP for muscle contraction comes from a certain source or sources. Check all that apply. A. Immediate supply through the phosphagen system B. Generation of glycogen C. Short-term supply through anaerobic cellular respiration D. Long-term supply through aerobic cellular respiration (mitochondria)

A, C, D

What are the events of smooth muscle contraction? Check all that apply. A. Initiated by Ca2+ binding to intracellular calmodulin B. Troponin activates tropomyosin C. Ca2+/calmodulin complex activates MLCK D. Activated MLCK to activate myosin ATPase

A, C, D

Which of the following is a true statement regarding muscular strength and conditioning? Check all that apply. A. Weight lifting does not increase the number of muscle fibers in a particular muscle exercised. B. Swimming will increase the number of muscle fibers in a particular muscle exercised. C. Blood capillary density will increase in slow-twitch fibers in response to training for a marathon. D. Long-term resistance training will increase the number of myofibrils in a particular muscle exercised. E. As muscle fibers become too large, mitosis causes them to divide into two.

A, C, D

Which of the following statements is true about the functions of cardiac muscle? Check all that apply. A. Cardiac muscle almost always utilizes aerobic respiration to obtain energy. B. Cardiac muscle cells require nervous innervation for stimulation. C. Cardiac muscle secures some if its calcium ions from the sarcoplasmic reticulum. D. When the chambers are filled with blood, the myocytes utilize tight junctions to resist separation. E. Autorhythmic cells allow the myocytes to contract consistently and regularly, efficiently pumping blood from the chambers.

A, C, E

Which of the following will result in an increase in muscle twitch strength? Check all that apply. A. Increase in stimulus frequency B. Increased acidity of sarcoplasm C. Increase in muscle temperature D. Decrease in stimulus frequency E. Increase in pre-twitch muscle length approaching optimal resting length

A, C, E

Which of these is not a function of the motor division of the nervous system? A-Transmits impulses from the viscera B-Transmits impulses to muscles and glands C-Involuntary control of the heart D-Conducts impulses from the CNS E-Voluntary control of skeletal muscle

A-Transmits impulses from the viscera

The presence of mitochondria and myoglobin facilitate _________ respiration in muscle cells. A-aerobic B- anaerobic

A-aerobic

One somatic motor neuron is stimulated by how many muscle fibers? A. 0 B. 1 C. 2 D. 3 E. 4

A. 0

A reason that muscle twitches become progressively stronger in treppe is A. Ca2+ accumulates in the sarcoplasm faster than the sarcoplasmic reticulum can reabsorb it B. ATP is regenerated fasted than it is consumed c. myosin heads show faster and faster power strikes D. more and more acetylcholine is released with each stimulus E. as the muscle warms up, aerobic respiration is accelerated

A. Ca2+ accumulates in the sarcoplasm faster than the sarcoplasmic reticulum can reabsorb it

Dystrophin, the protein that is defective in muscular dystrophy is normally found A. between the outermost myofilaments and the sarcolemma of a muscle fiber B. As a transmembrane protein of the sarcolemma C. in the Z discs of skeletal and cardiac muscle D. in the dense bodies of smooth muscle E. bridging the gap between the sarcolemma and synaptic knob

A. between the outermost myofilaments and the sarcolemma of a muscle fiber

Which of the following would be caused by contraction of smooth muscle? A. goose bumps B. blood leaving the left ventricle of the heart C. elevating the eyebrows D. blinking the eyelids E. deep inspiration

A. goose bumps

Cardiac muscle has very little capacity for regeneration because it lacks A. satellite cells B. endomysium C. sarcomeres D. dense bodies E. somatic nerve fibers

A. satellite cells

To stimulate muscle contraction, acetylcholine is released from the ___ into the synaptic cleft. A. synaptic knob B. junctional folds C. sarcoplasmic reticulum D. sarcolemma E. terminal cisterna

A. synaptic knob

The minimum stimulus needed to cause muscle contraction is called A. the threshold B. the latent period C. twitch D. recruitment E. innervation

A. the threshold

For relaxation to occur: Ach receptors close and Ca++ channels on the sarcoplasmic reticulum close. Ach receptors open and Ca++ channels on the sarcoplasmic reticulum close. Ach receptors close and Ca++ channels on the sarcoplasmic reticulum open. Ach receptors open and Ca++ channels on the sarcoplasmic reticulum open.

Ach receptors close and Ca++ channels on the sarcoplasmic reticulum close.

In general, a skeletal muscle is composed of: A)connective tissue sheaths B) nerves C) arteries D) veins E) muscle fibers

All of the above

Which are possible functions of skeletal muscles? A) maintenance of posture B) Both highly coordinated and localized simple movements C) Temperature support D) Support of certain body organs E) Regulation of the movement of material through certain body tracts

All of the above

Which sequence correctly lists the changes that allow the thick and thin filaments to slide past one another in skeletal muscle contraction? Attach - pivot - detach - return Attach - detach - pivot - return Pivot - attach - return - detach Pivot - attach - detach - return Return - pivot - attach - detach

Attach - pivot - detach - return

Check all that are proteins of thin filaments. A. Myosin B. Actin C. Troponin D. Titin (connectin) E. Tropomyosin

B, C, E

Check all that are characteristics of cardiac muscle. A. Cells are long and cylindrical. B. Cells are short and branching. C. Cells have multiple nuclei at the periphery of the cell. D. Cells have one or two nuclei in the center of the cell. E. They are composed of thick and thin filaments. F. The functional contractile unit is the sarcomere.

B, D, E, F

The administration of a drug that inhibits acetylcholinesterase would result in: A-poor muscle stimulation due to enhanced acetylcholine breakdown. B-enhanced stimulation of the muscle due to decreased acetylcholine breakdown. C-a failure to stimulate the muscle due to decreased acetylcholine release. D-enhanced stimulation of the muscle due to enhanced acetylcholine release.

B-enhanced stimulation of the muscle due to decreased acetylcholine breakdown.

The main way a body builder's muscles become larger is: A-hyperplasia. B-hypertrophy

B-hypertrophy

An end plate potential is an event that involves a gain of: A-negative charge for the cell, as sodium rapidly enters. B-positive charge for the cell, as sodium rapidly enters. C-negative charge for the cell, as potassium rapidly enters. D-positive charge for the cell, as potassium rapidly enters.

B-positive charge for the cell, as sodium rapidly enters.

Staircase" and "warm up" are alternative names for ___________, an increased muscle response to a constant stimulus. A-wave summation B-treppe C-isotony D-multiple motor unit summation E-incomplete tetany

B-treppe

A neuron conducting an impulse from the stomach wall to the CNS would be classified as a(n) __________ neuron. A-autonomic motor B-visceral sensory C-somatic sensory D-somatic motor

B-visceral sensory

An action potential has just arrived at an axon terminal. List the following events in the correct order: 1) cross-bridge formation 2) release of neurotransmitter from the presynaptic neuron 3) cross-bridge detachment 4) opening of ligand-gated cation channels 5) resetting (cocking) of the myosin head 6) calcium binds to troponin 7) power stroke 8) calcium is released from the terminal cisternae of the SR A- 8-2-4-6-1-7-3-5 B-8-2-4-6-1-7-5-3 C- 2-4-8-6-1-7-3-5 D-7-1-3-5-8-6-2-4

C- 2-4-8-6-1-7-3-5

Acetylcholine exerts its effect by: A-activating acetylcholinesterase. B-stimulating the motor neuron's synaptic knob. C-binding to receptors at the motor end plate. D-allowing calcium to enter the cell.

C-binding to receptors at the motor end plate.

In order for contraction to occur, the skeletal muscle fiber requires ______________. A-calcium. B-ATP. C-both calcium and ATP. D-neither calcium nor ATP.

C-both calcium and ATP.

Growth of the uterus during pregnancy is accomplished by _________ of its smooth muscle. A-neither hypertrophy nor hyperplasia B-both hypertrophy and hyperplasia C-hypertrophy but not hyperplasia D-hyperplasia but not hypertrophy

C-hypertrophy but not hyperplasia

Muscle tone is a result of _________ nervous system activity, and it acts to _________ joint position. A-involuntary, continuously vary B-voluntary, continuously vary C-involuntary, stabilize D-voluntary, stabilize

C-involuntary, stabilize

When smooth muscle is stretched for a prolonged period of time, it responds by: A-remaining the same length. B-contracting. C-relaxing.

C-relaxing.

Which of the following has the largest mitochondria A. slow oxidative fibers B. fast glycolytic fibers C. cardiac muscle D. smooth muscle E. intermediate fibers

C. cardiac muscle

A drug that inhibited acetylcholinesterase would result in: A. a failure to stimulate the muscle due to decreased Ach release. B. enhanced stimulation of the muscle due to enhanced Ach release. C. enhanced stimulation of the muscle due to decreased Ach breakdown. D. poor muscle stimulation due to enhanced Ach breakdown.

C. enhanced stimulation of the muscle due to decreased Ach breakdown.

If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be A. fatigue B. treppe C. incomplete tetanus D. complete tetanus E. flaccid paralysis

C. incomplete tetanus

The triads of a muscle fiber consists of A. two A bands and one I band B. two T tubules and one terminal cisterna C. two terminal cisternae and one T tubule D. two thin myofilaments and one thick myofilament E. two thick myofilaments and one thin myofilament

C. two terminal cisternae and one T tubule

A power stroke involves: A-a thick filament pushing an actin filament towards the nearest Z-line. B-a thin filament shortening in length and thereby shortening the sarcomere. C-an actin molecule pulling a myosin molecule toward the M-line. D-a myosin head pulling a thin filament toward the center of the sarcomere.

D-a myosin head pulling a thin filament toward the center of the sarcomere.

A motor unit consists of: A. multiple motor neurons and the one muscle fiber they control. B. multiple motor neurons and multiple muscle fibers. an end plate, T-tubule, and sarcoplasmic reticulum. C. one synaptic terminal button, a cleft, and an acetylcholine receptor. D. a single motor neuron and the multiple muscle fibers it controls.

D. a single motor neuron and the multiple muscle fibers it controls.

Exposure to Clostridium tetani causes continuous release of acetylcholine. What effect does this have on smooth muscle? A. flaccid paralysis B. spastic paralysis C. lockjaw D. no effect E. myocardial atrophy

D. no effect

The purpose of varicosities in motor nerve fibers in muscle physiology is A. to link the thin filaments to the inside of the sarcolemma in smooth muscle B. to reabsorb the decomposition products of acetylcholine after acetylcholinesterase breaks it down C. to enable each cardiac myocyte to directly stimulate its neighbors D. to release neurotransmitter onto smooth muscle cells E. to prevent single-unit smooth muscle cells from pulling apart

D. to release neurotransmitter onto smooth muscle cells

Which may occur as a result of muscle atrophy? A-Reduction in muscle size B-Fibers become weaker C-Muscle loses tone D-Fibers waste away and die E-All choices are correct

E-All choices are correct

To initiate a smooth muscle cell contraction, calcium enters the cell and binds to: A-a myosin head, which then activates calmodulin. B-a phosphatase, which then removes the tropomyosin blockade. C-troponin, which then activates myosin light chain kinase. D-myosin light chain kinase, which then hydrolyzes ATP. E-calmodulin, which then binds to and activates myosin light chain kinase.

E-calmodulin, which then binds to and activates myosin light chain kinase.

When an impulse arrives at the knob of the motor neuron, calcium: A-is released from synaptic vesicles. B-enters through active transport pumps and triggers the release of neurotransmitter. C-exits through voltage-gated channels and triggers neurotransmitter release. D-exits through active transport pumps and brings neurotransmitter with it. E-enters through voltage-gated channels and triggers the release of neurotransmitter.

E-enters through voltage-gated channels and triggers the release of neurotransmitter.

Which statement best describes the goal of medications used to treat myasthenia gravis? A. to increase the number of acetylcholine receptors B. to decrease the number of synaptic vesicles C. to promote multiple motor unit summation D. to inhibit CA2+ release from the sarcoplasmic reticulum E. to inhibit the function of cholinesterase

E. to inhibit the function of cholinesterase

The spring like property that returns muscle to its original length after a contraction ends is called what?

Elasticity

A dark band formed by parallel thick filaments that partly overlap the thing filaments is known as an H band True False

False

Which letter is associated with the light band and contains thin filaments only? Z H M I A

I

Which contraction occurs when you try (unsuccessfully) to move a wall? Isotonic Isometric

Isometric

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

It is responsible for locomotion.

Which of the following is NOT true of the latch state of smooth muscle contraction? It occurs when the phosphate is removed while the cross-bridges are not attached to actin. It explains why smooth muscle can sustain tension for long periods of time. Myosin phosphatase removes the phosphate group from myosin. It allows contraction without a large energy expenditure. It occurs when the phosphate is removed while the cross-bridges are attached to actin.

It occurs when the phosphate is removed while the cross-bridges are not attached to actin.

Which is the neurotransmitter that causes the release of calcium ions from reservoirs within the muscle cell and thereby initiates the steps of contraction? 1.Acetylcholine 2.Norepinephrine 3.Rubitussin 4.Serotonin 5.Acetylcholinesterase

1.Acetylcholine

The action potential of a muscle fiber occurs: 1.within the sarcoplasmic reticulum. 2.along the sarcolemma and down the T-tubules. 3.in the mitochondria. 4.at the end plate.

2.along the sarcolemma and down the T-tubules.

Which fibers dominate many of the back and calf muscles that contract almost continually to maintain posture? Slow Fast Intermediate

Slow

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

The muscle lengthens but tension remains constant.