HS&F: Chapter 7 - Muscular System

E

______________ are located in the walls of the stomach and small intestine. a) Cardiac muscle cells b) Both cardiac and smooth muscle cells c) Both skeletal and cardiac muscle cells d) Skeletal muscle cells e) Smooth muscle cells

A

Cardiac muscle a) is under involuntary control. b) has long, cylindrical cells c) has many nuclei per cell. d) has no striations. e) has all of these characteristics.

E

The letter A in this figure represents a) the M line. b) the A band. c) a Z disk. d) the I band. e) a sarcomere. https://www.eztestonline.com/249515/1321628753727660059.tp4?REQUEST=SHOWmedia&media=2image001.png

B

_____________ are striated muscle cells. a) Both cardiac and smooth muscle cells b) Both skeletal and cardiac muscle cells c) Smooth muscle cells d) Cardiac muscle cells e) Skeletal muscle cells

E

______________ are joined to each other by structures called intercalated disks. a) Skeletal muscle cells b) Smooth muscle cells c) Both skeletal and cardiac muscle cells d) Both cardiac and smooth muscle cells e) Cardiac muscle cells

A

A condition known as flaccid paralysis: a) arises because the muscle is incapable of contracting in response to nervous stimulation b) arises because acetylcholinesterase levels are artificially low c) arises because the muscle is incapable of relaxing d) arises because acetylcholine in the neuromuscular junction never breaks down e) all of the above are true.

E

A high-energy molecule that can be quickly used to produce ATP is a) glucose. b) water. c) lactic acid. d) carbon dioxide. e) creatine phosphate.

E

A muscle fiber will not respond to a stimulus until that stimulus reaches the a) relaxation level. b) recruitment level. c) tetany. d) rigor mortis level. e) threshold level.

C

A muscle located on either side of the linea alba, which flexes the waist and is crossed by tendinous intersections is the a) external intercostal. b) external abdominal oblique. c) rectus abdominis. d) transversus abdominis. e) erector spinae.

D

A single motor neuron and all the skeletal muscle fibers it innervates is called a a) neuromuscular junction. b) synapse. c) synaptic cleft. d) motor unit. e) presynaptic terminal.

E

Acetylcholine a) is the neurotransmitter at the neuromuscular junction. b) is broken down by acetylcholinesterase. c) binds to receptors on the muscle cell membrane. d) causes an influx of sodium ions into the muscle cell when bound to its receptor. e) has all of these characteristics.

C

Aerobic respiration a) results in the breakdown of glucose to yield ATP and lactic acid. b) is much less efficient than anaerobic respiration c) can use fatty acids and amino acids to generate ATP d) can occur much faster than anaerobic respiration e) all of the above are true of aerobic respiration

E

Aerobic respiration: a) requires oxygen b) breaks down glucose c) produces ATP, CO2 and H2O d) takes place in mitochondria located within the muscle fiber sarcoplasm e) all of the above are true of aerobic respiration

C

All of the following are the effects of aging on the muscular system EXCEPT: a) reduction in muscle mass b) increase in response time to stimulus c) increase in the number of myofilaments in each fiber d) reduction in number of motor units e) reduction in surface area of the neuromuscular junction

C

An anterior thigh muscle that extends the leg is the a) hamstring group. b) iliopsoas. c) quadriceps femoris. d) sartorius. e) adductor group.

A

Anaerobic respiration a) produces lactic acid within the muscle and produces an oxygen deficit. b) produces the most ATP's for each glucose molecule broken down. c) is used by all cells during sustained periods of exercise. d) produces an oxygen deficit. e) produces lactic acid within the muscle.

E

Caffeine aids in the movement of calcium ions across membranes by both making it easier for the Ca++ channels to open and by holding the channels open longer. How would the administration of caffeine to a muscle fiber affect its contraction? a) Caffeine would increase the strength of the fiber's contraction. b) Caffeine would allow more cross bridges to form in the fiber. c) Caffeine would increase the duration of the fiber's contraction. d) At high enough levels, caffeine would cause the muscle fiber to contract without a signal from the associated motor neuron. e) Caffeine would have all of these effects.

A

Calcium ions a) are returned to the sarcoplasmic reticulum by active transport. b) bind to myosin myofilaments. c) provide the energy for muscle contraction. d) are released from the T tubules by active transport. e) have both bind to myosin myofilaments and are returned to the sarcoplasmic reticulum by active transport as normal properties.

A

Contractibility is the ability of skeletal muscle to a) shorten with force. b) be stretched. c) recoil to their original resting length. d) lengthen passively. e) respond to a stimulus.

C

Curare is a poison used by South American Indians. It is known to bind to ACh receptors preventing the binding of ACh. What effect would it have on muscle function? a) The muscle fibers would contract uncontrollably and continually. b) Both the muscle fibers would contract uncontrollably and continually and the action of acetylcholinesterase would be inhibited causing increased contraction would occur. c) The muscle fibers would not contract because the Na+ channels which cause depolarization of the muscle fiber membrane are never signaled to open. d) The action of acetylcholinesterase would be inhibited causing increased contraction. e) The pre-synaptic release of ACh would be inhibited, therefore the muscle would not contract.

A

Excitability is the ability of skeletal muscle to a) respond to a stimulus. b) lengthen passively. c) recoil to their original resting length. d) shorten with force. e) be stretched.

B

Given these events: 1) calcium ions move along their concentration gradient 2) action potential in cell membrane 3) opening of ion channels in sarcoplasmic reticulum 4) action potential in T tubules 5) actin to myosin cross-bridges form Arrange them in the correct sequence as they participate during skeletal muscle contraction. a) 2, 1, 5, 3, 4 b) 2, 4, 3, 1, 5 c) 5, 3, 4, 2, 1 d) 1, 2, 5, 3, 4 e) 1, 5, 4, 3, 2

C

In the figure, the letter B best represents the a) arrector pili muscle. b) cortex. c) medulla. d) papilla. e) cuticle. https://www.eztestonline.com/249515/1321628753727660059.tp4?REQUEST=SHOWmedia&media=image002.png

A

Mary Thon, a long-distance runner, asks her coach why it is so difficult to have a "finishing kick" (sprinting the last hundred yards to the finish line). Her coach should reply: a) Anaerobic activities like sprinting are limited by available glucose and rate of buildup of lactic acid. b) There is no physiological reason why the finishing kick should be difficult. c) Sprinting requires fatty acids, which are likely to be gone at that point. d) She has already built up an oxygen deficit from too much aerobic exercise. e) Sprinting requires large amounts of oxygen, and she doesn't have much available at that point.

E

Organophospahtes cause spastic paralysis because: a) their action produces a constant stimulus to contract b) they inhibit the activity of acetylcholinesterase c) they prevent the degradation of acetylcholine in the neuromuscular junction d) they prevent the muscles from relaxing e) all of the above are true

D

Put the following events in chronological order. (Some of the steps may be missing.) 1) Ca++ floods into the pre-synaptic neuron. 2) Ach (Acetylcholine) binds to ACh receptors in the sarcolemma. 3) Na+ floods into the post-synaptic muscle cell. 4) The A.P arrives at the pre-synaptic terminal causing Ca++ channels to open. 5) Ach from the synaptic vesicles spills into the pre-synaptic cleft. 6) A post-synaptic action potential results in the muscle fiber (depolarization). a) 3, 6, 5, 4, 1, 2 b) 4, 1, 2, 5, 3, 6 c) 6, 3, 2, 5, 1, 4 d) 4, 1, 5, 2, 3, 6 e) 2, 1, 6, 3, 4, 5

E

Satellite cells: a) are undifferentiated cells below the endomysium b) can differentiate and divide into new functional muscle fibers c) are stimulated by the destruction of existing muscle fibers d) are stimulated by intensive strength training e) all of the above are true of satellite cells

E

The ________ is the functional unit of skeletal muscle because it is the smallest portion of the skeletal muscle capable of ___________. a) muscle fiber, receiving a stimulus b) sarcomere, receiving a stimulus c) muscle fiber, contracting d) myofibril, contracting e) sarcomere, contracting

B

The _________ is the smooth ER of a muscle fiber and stores calcium ions. a) T tubules b) sarcoplasmic reticulum c) sarcomere d) sarcolemma e) sarcoplasm

B

The ___________ is a group of muscle cells surrounded by perimysium. a) myofilament b) muscle fasciculus c) muscle fiber d) myofibril e) whole skeletal muscle

E

The ___________ is the most stationary end of a muscle. a) insertion b) antagonist c) prime mover d) agonist e) origin

C

The ____________ consists of only actin myofilaments. a) H zone b) M line c) I band d) Z disk e) A band

B

The ____________ is the end of a muscle attached to a bone undergoing the greatest movement. a) agonist b) insertion c) origin d) prime mover e) antagonist

B

The anterior forearm muscles a) perform both flexion and supination at the wrist. b) flex the wrist and fingers. c) supinate the forearm. d) are called intrinsic hand muscles. e) extend the wrist and fingers.

E

The muscle that works in opposition to another muscle is the a) prime mover. b) origin. c) insertion. d) agonist. e) antagonist.

B

The specific molecules that provide calcium binding sites on actin are __________ molecules. a) titin b) troponin c) myosin d) tropomyosin

D

What ensures that one action potential in the neuron yields only one action potential in the skeletal muscle fibers of the stimulated motor unit and therefore only one contraction per fiber? a) the amount of calcium that enters the pre-synaptic cell b) the rate of diffusion of acetylcholine across the synaptic cleft c) the number of muscle fibers that make up the motor unit d) enzymatic breakdown of acetylcholine by acetylcholinesterase e) All of these ensure this one to one ratio.

D

Which of the following areas of the sarcomere disappear when the sarcomere is completely contracted? a) I band b) Z disks c) A band d) H zone e) M line

C

Which of the following motor units would allow for greater muscular control? a) a motor unit made up of a motor neuron and twenty muscle fibers. b) a motor unit made up of a motor neuron and ten muscle fibers. c) a motor unit made up of a motor neuron and five muscle fibers. d) a motor unit made up of a motor neuron and one thousand muscle fibers. e) a motor unit made up of a motor neuron and one hundred muscle fibers.

E

Which of the following statements is FALSE? a) A muscle cell is also called a muscle fiber. b) The sarcolemma is a specialized plasma membrane of a muscle cell. c) Normally, skeletal muscle fibers do not contract unless they are stimulated by motor neurons. d) When muscles contract, the actin myofilaments are pulled towards the M-lines (the center), thus decreasing the overall sarcomere length. e) During muscle contraction, the actual length of the actin and myosin molecules changes.

C

_________ is a single muscle cell. a) myofilament b) muscle fasciculus c) muscle fiber d) whole skeletal muscle e) myofibril