Deck 9: The Muscular System: Skeletal Muscle Tissue and Muscle Organization

Question 1

The portion of a sarcomere that contains the M line, H band and the zone of overlap is the ________.

A) I band
B) M line
C) A band
D) H band
E) Z line

Answer 1

C

Question 2

Delayed-onset muscle soreness is potentially caused by microscopic ruptures at the ________ of the sarcomeres.

A) M line
B) I band
C) H band
D) Z line
E) A band

Answer 2

D

Question 3

The structures within the muscle fiber that shorten to cause skeletal muscle fiber contraction are (the)________.

A) myoneural junctions
B) myofibrils
C) myosatellite cells
D) neuromuscular synapses
E) myoblasts

Answer 3

B

Question 4

The complex known as the triad consists of ________.

A) actin, myosin, and myofilaments
B) one A band, one H zone, and one I band
C) one transverse tubule and two terminal cisternae
D) myofilaments, myofibrils, and sarcomeres
E) one sarcomere, one sarcoplasmic reticulum, and one sarcoplasm

Question 5

Why are skeletal muscles called voluntary?

A) These muscles maintain a constant rhythm of contraction.
B) Their contractions can be consciously controlled.
C) Only these muscles are stimulated to contract by the central nervous system.
D) Contraction of specific muscles occurs to maintain body posture and body position.
E) All of the answers are correct.

Question 6

How many skeletal muscles are there in the muscular system?

A) 50
B) 206
C) thousands
D) 700+
E) 116

Question 7

Which of these orders of functional muscle structures progresses from the smallest to largest in diameter?

A) muscle, fascicle, muscle fiber, myofibril
B) fascicle, myofibril, muscle fiber, filament
C) fascicle, muscle fiber, myofibril, muscle
D) muscle, muscle fiber, myofibril, fascicle
E) myofibril, muscle fiber, fascicle, muscle

Question 8

What characteristic of muscle tissue allows it to respond to stimulation by the nervous system?

A) excitability
B) elasticity
C) extensibility
D) contractility
E) None of the answers are correct.

Question 9

The connective tissue surrounding a fascicle is called ________.

A) endomysium
B) epimysium
C) perimysium
D) a tendon
E) an aponeurosis

Question 10

The epimysium, which separates the muscle from surrounding tissues and organs, is connected to the ________.

A) superficial fascia
B) subserous fascia
C) deep fascia
D) aponeuroses
E) None of the answers are correct.

Question 11

Actinin molecules form an open meshwork at the ________.

A) Z line
B) M line
C) H band
D) I band
E) A band

Question 12

The layers of connective tissue surrounding a skeletal muscle from the inside to the outside in correct order are ________.

A) endomysium, perimysium, and epimysium
B) epimysium, endomysium, and perimysium
C) epimysium, perimysium, and endomysium
D) endomysium, epimysium, and perimysium
E) perimysium, epimysium, and endomysium

Question 13

Smooth muscles are primarily used to ________.

A) generate heat
B) pump blood through the circulation
C) push fluid and solids along the digestive tract
D) provide voluntary movements to the body
E) pull on bones of the skeleton

Question 14

Which of the following is the type of muscle that pushes blood through the blood vessels of the cardiovascular system?

A) skeletal muscle
B) cardiac muscle
C) smooth muscle
D) appendicular muscle
E) None of the answers are correct.

Question 15

Which of the following is a function of skeletal muscle?

A) produce skeletal movement
B) maintain posture
C) support soft tissues
D) maintain body temperature
E) All of the answers are correct.

Question 16

Skeletal muscle fibers arise from embryonic cells called ________.

A) myotomes
B) myoblasts
C) myomeres
D) myofilaments
E) myofibrils

Question 17

The sarcoplasmic reticulum is (the)________.

A) sarcolemma of skeletal muscle fibers
B) cytoplasm of skeletal muscle fibers
C) a membrane complex in skeletal muscles similar to smooth endoplasmic reticulum
D) extension of the skeletal muscle sarcolemma into the cell
E) a membrane complex in skeletal muscles similar to rough endoplasmic reticulum

Question 18

The attachment of a muscle to a bone is called ________.

A) a bursa
B) an aponeurosis
C) a ligament
D) a capsule
E) either a tendon or an aponeurosis

Question 19

Which of the following features is NOT characteristic of muscle tissues?

A) excitability
B) cognitive ability
C) contractility
D) extensibility
E) elasticity

Question 20

Why does a skeletal muscle fiber have more than one nucleus?

A) During development, groups of embryonic cells called myoblasts fuse together to form a single muscle fiber.
B) During development, the nucleus of each myoblast replicates several times.
C) During development, the sarcolemmae of newly formed muscle fibers disintegrate, making many muscle cells into one.
D) During muscular activity, parts of each muscle fiber break down, and the remaining parts, including their nuclei, fuse into new combination fibers.
E) All of the answers are correct.

Question 21

The neurotransmitter involved in the process of contraction in skeletal muscles is ________.

A) ATP
B) acetylcholine
C) troponin
D) globulin
E) serotonin

Question 22

The motor neuron releases acetylcholine, which then binds to receptors sites on a special region of the sarcolemma called ________.

A) a T tubule
B) the motor unit
C) a fascicle
D) a motor end plate
E) the sarcoplasmic reticulum

Question 23

Troponin assists in controlling the interaction between myosin heads and thin filaments by ________.

A) forming a long chain that covers the active sites of thin filaments
B) storing calcium ions in the troponin-tropomyosin complex
C) binding to myosin heads, which allows tropomyosin to pivot, thereby exposing the active sites
D) assisting in the formation of the myofilaments
E) binding calcium ions to produce a change in the orientation of the troponin-tropomyosin complex

Question 24

Thick (myosin)and thin (actin)filaments together form ________.

A) myofibrils
B) the H band
C) a triad
D) Z discs
E) the I band

Question 25

The smallest functional units of the muscle fibers are the ________.

A) fascicles
B) sarcomeres
C) myofilaments
D) cisternae
E) neuromuscular synapses

Question 26

Each skeletal muscle fiber is controlled by a single ________.

A) synaptic cleft
B) motor end plate
C) triad of transverse tubule and terminal cisternae
D) motor neuron whose cell body is located inside the central nervous system
E) neurotransmitter

Question 27

The ________ is a dense irregular connective tissue layer that surrounds the entire skeletal muscle.

A) perimysium
B) sarcolemma
C) epimysium
D) sarcoplasmic reticulum
E) endomysium

Question 28

Between the endomysium and the muscle fibers lie a number of stem cells that aid in the repair of damaged muscle tissues. These are the ________ cells.

A) myoblast
B) myofibril
C) isotropic
D) myosatellite
E) myosin

Question 29

Regarding the effect of sarcomere length on tension production, a very highly stretched muscle (increased sarcomere length above normal 3.1 µm)will produce a contraction (% maximum tension)that is ________.

A) optimal (100%)
B) much greater than average (80-90%)
C) fairly weak (20-40%)
D) slightly stronger than resting position (~10%)
E) None of the answers are correct.

Question 30

Which of the following molecules or ions are absent following death and leads to rigor mortis?

A) acetylcholine
B) acetylcholinesterase
C) ATP
D) calcium
E) None of these are correct.

Question 31

A skeletal muscle is divided into a series of internal compartments, each of which contains a bundle of muscle fibers called a ________.

A) myofibril
B) sarcomere
C) triad
D) cross-bridge
E) fascicle

Question 32

The sliding mechanism of myofilaments works when ________.

A) the thick filaments detach from the muscle tendon
B) the myosin heads of the thick filaments bind to active sites on the actin molecules of the thin filaments
C) the myosin heads pivot away from the M line toward the Z lines
D) the troponin-tropomyosin complex interacts with the actin molecules
E) calcium ions bind to active sites on the actin molecules of the thin filaments

Question 33

The area of a myofibril where there are no actin filaments is the ________.

A) A band
B) Z line
C) I band
D) M line
E) H band

Question 34

Which of the following ions is the trigger for a muscle contraction?

A) sodium
B) chloride
C) calcium
D) potassium
E) acetylcholine

Question 35

When contraction occurs, ________.

A) the A band remains constant
B) the H band gets smaller
C) the I band begins to disappear
D) the Z lines move closer together
E) All of the answers are correct.

Question 36

Tropomyosin and troponin are which of the following types of molecules?

A) functional hormone
B) secretory protein
C) regulatory protein
D) enzyme
E) accessory protein

Question 37

The function of T tubules is to ________.

A) bind muscle fibers together at the neuromuscular synapse
B) separate the terminal from the motor end plate of the skeletal muscle fiber
C) help distribute the electrical impulse, which triggers the release of calcium ions by the sarcoplasmic reticulum
D) bind actin and myosin molecules together
E) release acetylcholine into the synaptic cleft

Question 38

The connective tissue that surrounds each skeletal muscle fiber and binds each muscle fiber to its neighbor is the ________.

A) endosteum
B) endomysium
C) epimysium
D) periosteum
E) perimysium

Question 39

The sarcoplasmic reticulum stores ________.

A) oxygen
B) glucose
C) ATP
D) calcium ions
E) glycogen

Question 40

What symptoms accompany fibromyalgia?

A) temporomandibular joint disorder
B) irritable bowel syndrome
C) anxiety
D) tension headaches
E) All of the answers are correct.

Question 41

Slow muscle fibers ________.

A) are supported by anaerobic metabolism
B) take twice as long to contract after stimulation as do fast fibers
C) can continue to contract long after fast fibers have fatigued
D) have less oxygen than do fast fibers
E) None of the answers are correct.

Question 42

The enzyme that is partly responsible for shutting down a muscle contraction is ________.

A) actinin
B) actinase
C) acetylcholinesterase
D) titin
E) glycolytic enzyme

Question 43

While wearing a cast due to a broken bone, muscles shrink due to the process of ________.

A) recruitment
B) cell division
C) hypertrophy
D) atrophy
E) chronic inflammation, or swelling

Question 44

What is the significance of the change in membrane potential of the T tubules within the sarcolemma?

A) It has no role, because this phenomenon does not occur.
B) It triggers the sarcoplasmic reticulum to release of calcium ions.
C) This change is caused by the release of actin and myosin molecules.
D) This change is caused by the displacement of actin and myosin molecules.
E) None of the answers are correct.

Question 45

When all of the motor units of a muscle contract at the maximal rate of stimulation, it leads to the production of ________.

A) the longest contraction
B) the fastest contraction
C) multiple motor unit summation
D) peak tension
E) fast, long contractions

Question 46

In muscles that have been repeatedly stimulated to produce near-maximal tension, the net effect is ________.

A) hypertrophy
B) recruitment
C) atrophy
D) reduced tone
E) None of the answers are correct.

Question 47

The steady increase in muscular tension produced by increasing the number of active motor units is called ________.

A) muscle tone
B) a muscle twitch
C) muscle spindles
D) peak tension
E) recruitment

Question 48

Which of the following events occurs in a muscle that is relaxing?

A) The muscle fiber shortens.
B) AChE is present in the synaptic cleft.
C) Released calcium ions are present.
D) Myosin heads bind to active sites on the thin filaments.
E) Hydrolysis of ATP occurs.

Question 49

Slow fibers primarily use which of the following substrates for energy?

A) glycogen
B) lipids and carbohydrates through the anaerobic pathway
C) carbohydrates, lipids, and amino acids through the aerobic pathway
D) anaerobic metabolism
E) protein

Question 50

Slow twitch fibers appear red due to the intracellular storage of ________.

A) nebulin
B) titin
C) hemoglobin
D) glycogen
E) myoglobin

Question 51

When acetylcholine binds to receptors on the motor end plate, ________ occurs immediately.

A) vesicular enzymatic activity
B) cross-bridge formation
C) ATP-myosin binding
D) an action potential
E) myosin head pivoting

Question 52

The muscle fiber typethat contains densely packed myofibrils, large glycogen reserves, and relatively few mitochondria, is called ________.

A) fast fibers
B) slow fibers
C) intermediate fibers
D) cardiac fibers
E) smooth fibers

Question 53

What type of muscular activity is present in a muscle at rest?

A) There is no activity.
B) There is some activity that causes the muscle to make continual tiny movements.
C) Motor units activate partially in a unified wavelike motion.
D) Motor units activate in a random pattern to cause slight constant tension, known as muscle tone.
E) There are large amounts of short contractions.

Question 54

The number of cells per motor unit in the leg muscles can reach up to ________.

A) one hundred
B) less than a dozen
C) millions
D) hundreds
E) many thousands

Question 55

By varying the ________ at any one time, the nervous system provides precise control over the pull exerted by the muscle.

A) reflexes triggered
B) concentration of glycolytic enzymes
C) number of motor units activated
D) energy reserves utilized
E) degree of muscle atrophy

Question 56

Which of the following events occurs first?

A) Myosin cross-bridges attach to actin.
B) Calcium ions are released from the sarcoplasmic reticulum.
C) Calcium binds to troponin.
D) The myosin head pivots toward the M line.
E) The myosin head binds ATP and detaches from actin.

Question 57

Skeletal muscle fiber contractions are caused by the interaction between the ________ and the ________ filaments of the sarcomeres.

A) thin; nebulin
B) titin; thin
C) thick; nebulin
D) thin; thick
E) titin; thick

Question 58

When a resting muscle contracts only enough to produce tension without movement, this is an example of ________.

A) activation
B) muscle tone
C) hypertrophy
D) atrophy
E) twitch

Question 59

When one motor neuron fires a single action potential the result affects one ________.

A) upper motor neuron
B) synaptic cleft
C) lower motor neuron
D) motor unit
E) sensory unit

Question 60

When a single motor neuron controls a greater number of muscle fibers in a motor unit, ________.

A) the greater the number of stimuli will be required to produce a contraction
B) each contraction will last longer
C) the muscle contraction will be slower
D) the less precise the control will be
E) None of the answers are correct.

Question 61

Regarding a typical muscle insertion, which of the following is true?

A) The insertion moves more than does the origin.
B) The insertion is proximal to the origin.
C) If a muscle extends between a broad aponeurosis and a narrow tendon, the aponeurosis is the insertion.
D) If there are several tendons at one end of a muscle and just one at the other, there are multiple insertions.
E) All of the answers are correct.

Question 62

A bundle of muscle fibers within a skeletal muscle body is called a ________.

A) fascicle
B) perimysium
C) muscle sheath
D) myofiber
E) myofilament

Question 63

How does a muscle named lateralis differ from one named latissimus?

A) There is no difference; the two terms are synonymous.
B) Lateralis refers to the side of the organism, whereas latissimus refers to the width of the structure.
C) Latissimus means the structure is larger than one that is merely lateralis.
D) Two muscles so named would always have completely different functions.
E) A latissimus structure is always deep to a lateralis structure.

Question 64

In the case of the triceps brachii, the shoulder is the ________; the olecranon is the ________.

A) origin; insertion
B) insertion; origin
C) agonist; antagonist
D) synergist; fixator
E) None of the answers are correct.

Question 65

The triceps brachii and biceps brachii are good examples of ________.

A) muscles that flex the elbow
B) an agonist-antagonist pair
C) synergists
D) agonists
E) antagonists

Question 66

If a muscle has a tendon that branches within the muscle tissue, it is a ________.

A) sphincter muscle
B) parallel muscle
C) circular muscle
D) multipennate muscle
E) None of the answers are correct.

Question 67

Two factors that are used to determine the classification of a skeletal muscle are
(1)the arrangement of the muscle fibers.
(2)the structural arrangement relative to the direction of the pull.
(3)the overall size of the muscle.
(4)the amount of connective tissue present within the muscle.
(5)the number of tendons connected to the muscle.

A) 1 and 2
B) 2 and 3
C) 3 and 4
D) 4 and 5
E) 1 and 3

Question 68

What does the term longissimus in a muscle name primarily indicate about that muscle?

A) the muscle location in the body
B) the muscle length
C) the manner in which the fibers of the muscle are oriented
D) the insertion of the muscle fibers is oriented with respect to the long axis of the body
E) the action of the muscle

Question 69

What does the name flexor carpi radialis most likely mean?

A) It is a forearm muscle whose primary function is synergistic to that of the biceps brachii muscle.
B) It is a lateral forearm muscle that flexes at the wrist.
C) It is a convergent muscle found along the radial border of the forearm.
D) The muscle originates at the wrist.
E) All of the answers are correct.

Question 70

Muscle fibers can have various arrangements. The most powerful arrangement, in which more tension is generated during contraction, is called ________.

A) circular
B) parallel
C) pennate
D) convergent
E) None of the answers are correct.

Question 71

A word in a muscle name that indicates it is a pear-shaped muscle might be ________.

A) splenius
B) piriformis
C) pectinate
D) teres
E) pyramidal

Question 72

Slow muscle fibers contain large amounts of the oxygen-binding protein ________.

A) myoglobin
B) calmodulin
C) titin
D) nebulin
E) troponin

Question 73

The biceps brachii is an example of a muscle with its fascicle oriented in a ________ fashion.

A) convergent
B) parallel
C) bipennate
D) circular
E) multipennate

Question 74

A very good sprinter is likely to have ________.

A) more slow twitch fibers than average
B) more intermediate fibers than average
C) more fast twitch fibers than average
D) average muscles; performance is based solely on training
E) None of the answers are correct.

Question 75

A muscle whose contraction is mostly responsible for a movement is said to be the ________ for that movement.

A) synergist
B) agonist and fixator
C) antagonist
D) fixator
E) agonist and prime mover

Question 76

An intermediate fiber contracts fast, but it has more ________ and greater resistance to fatigue than a fast fiber.

A) calcium ions
B) myoglobin
C) ribosomes
D) oxygen-binding pigments
E) mitochondria

Question 77

The muscles surrounding the entrances of the digestive and urinary tracts are classified as ________.

A) convergent
B) bipennate
C) parallel
D) multipennate
E) circular

Question 78

In a ________ muscle, the muscle fibers are based over a broad area, but all the fibers come together at a common attachment site.

A) convergent
B) spiral
C) circular
D) multipennate
E) parallel

Question 79

Most of the skeletal muscle fibers in the body are called ________ fibers, in reference to their duration of contraction following stimulation.

A) red
B) intermediate
C) slow
D) fast
E) All of the answers are correct.

Question 80

The adductor magnus muscle is so named, partially due to the ________.

A) size of the muscle
B) shape of the muscle
C) parallel versus pennate arrangement of its fibers
D) orientation of its muscle fibers
E) location of the muscle