Deck 12: A: Physiology of the Muscular System

Question 1

A neuromuscular junction is a type of connection called a synapse.

Answer 1

True

Question 2

Muscle fibers of skeletal muscle contain several nuclei.

Answer 2

True

Question 3

A compound that mimics the action of acetylcholine at the neuromuscular junction would cause muscles to become flaccid.

Answer 3

False

Question 4

When sarcomeres shorten,myofibrils also shorten.

Question 5

Myosin filaments attach to the Z disk.

Question 6

Hemoglobin carries oxygen in red blood cells,and myoglobin stores oxygen in muscle fibers.

Question 7

The cell membrane of a muscle fiber is called the sarcoplasmic reticulum.

Question 8

Anaerobic respiration is the first choice of the muscle cell for the production of ATP.

Question 9

T-tubules are perpendicular to muscle fibers.

Question 10

The following are characteristics that allow muscles to function as they do: excitability,contractility,extensibility,and regulation.

Question 11

ATP is made up of adenine,ribose sugar,and three phosphate groups.

Question 12

Myofibrils contain several sarcomeres lined up end to end.

Question 13

A triad consists of a T-tubule sandwiched between sacs of the sarcoplasmic reticulum.

Question 14

Myosin filaments interact with actin filaments during muscle contraction.

Question 15

Another name for muscle cells is muscle fibers.

Question 16

At rest,troponin covers the active sites on the actin molecules.

Question 17

Muscle fibers use creatine phosphate to restore their ATP population.

Question 18

The protein molecule that has heads jutting out for cross-bridging is called myosin.

Question 19

Muscle cells have one nucleus and one mitochondrion.

Question 20

The sliding filament theory is the current model of muscle contraction.

Question 21

Skeletal muscle organs contract on the all-or-none principle.

Question 22

Treppe is a steep increase in the strength of contractions that can be seen in a series of twitch contractions.

Question 23

Slow fibers are also called white fibers because they contain a low concentration of myoglobin.

Question 24

Muscles with less-than-normal tone are described as in tetanus.

Question 25

Endurance training usually results in muscle hypertrophy.

Question 26

In psychological muscle fatigue,an individual cannot contract his or her muscles.

Question 27

The study of muscle activity is called myography.

Question 28

During an isotonic contraction,the tension produced by the myosin cross-bridges cannot overcome the load placed on the muscle.

Question 29

The more precise the muscle movement,the greater the number of muscle fibers activated by a motor neuron.

Question 30

Cardiac muscle is similar to skeletal muscle in that both form strong,electrically coupled junctions with other fibers.

Question 31

Smooth,sustained contractions are called treppe.

Question 32

The degree of a muscle's strength is influenced by many factors,including its metabolic condition and number of motor units recruited.

Question 33

A motor neuron plus the muscle fibers to which it attaches is called a motor unit.

Question 34

A tetanic contraction is stimulated by a single stimulus.

Question 35

Convulsions are abnormal,uncoordinated tetanic contractions of varying groups of muscles.

Question 36

Muscles contract more forcefully after they have contracted a few times.

Question 37

For continued,efficient nutrient catabolism by muscle fibers,both glucose and oxygen are required.

Question 38

The type of contraction exhibited by normal skeletal muscles most of the time is called tetanus.

Question 39

The graded strength principle states that skeletal muscles contract with varying degrees of strength at different times.

Question 40

As resistance increases,the number of motor units needed to overcome that resistance has to increase.

Question 41

Muscle pain may also be referred to as muscular dystrophy.

Question 42

In visceral smooth muscle,gap junctions join individual smooth muscle fibers into large,continuous sheets.

Question 43

The shorter a muscle prior to contraction,the more tension it will be able to generate.

Question 44

The thin myofilament is myosin,whereas the thick myofilament is actin.

Question 45

Fibrillation is a tetanic contraction of cardiac muscle.

Question 46

Skeletal muscle has a great ability to stretch.

Question 47

Muscle cells produce heat by the process of catabolism.

Question 48

Rigor mortis is caused because of damage done to the sarcolemma after death.

Question 49

A motor neuron is considered part of the neuromuscular junction.

Question 50

A satellite cell can fuse with myocytes during strength training to make larger muscle fibers.

Question 51

Duchenne (pseudohypertrophic)muscular dystrophy is the most common type of muscular dystrophy.

Question 52

The cell membrane of a muscle fiber is called the sarcolemma.

Question 53

Oxygen molecules in the sarcoplasm are bound to the troponin molecule.

Question 54

One I-band resides within two sarcomeres.

Question 55

Cramps are painful,involuntary muscle spasms.

Question 56

Myocyte is another term for muscle cells.

Question 57

T-tubules are found in all types of muscle tissue.

Question 58

Isometric contraction is a contraction in which the tone or tension within a muscle remains the same but the length of the muscle changes.

Question 59

Myoglobin gives red muscle fibers their red color.

Question 60

Actin,troponin,and tropomyosin are present on the thick myofilament.

Question 61

Tetanus will not occur in an individual with an up-to-date tetanus vaccination.

Question 62

Myosin heads release from the actin molecule when ATP attaches to it.

Question 63

When troponin and calcium combine,it causes actin to shift and allows the myosin to form cross-bridges.

Question 64

The difference between red and white fibers is the amount of glycogen.

Question 65

The release of calcium by the sarcoplasmic reticulum begins the contraction phase of a twitch contraction.

Question 66

Because of the elasticity of the muscle fiber,as soon as the contraction stops,the sarcomere goes back to its pre-contraction length.

Question 67

The sarcoplasmic reticulum in muscle cells is identical to the rough endoplasmic reticulum in other cells.

Question 68

The A-band in a relaxed sarcomere is composed of only actin.

Question 69

T-tubules are formed by an inward extension of the sarcolemma.

Question 70

When the sarcomere contracts,the A-bands become smaller.

Question 71

The motor end plate is part of the neuromuscular junction.

Question 72

The sarcoplasmic reticulum continually pumps calcium ions out of the sarcoplasm and stores them in sacs.

Question 73

Myofibrils make up myofilaments.

Question 74

When the sarcomere contracts,the I-bands become smaller.

Question 75

The H-zone in a relaxed sarcomere is composed of only myosin.

Question 76

Contraction of a small fraction of the total number of fibers in a muscle produces muscle tone.

Question 77

The anabolism of protein by muscle cells produces heat for the body.

Question 78

Muscles with less tone than normal are described as flaccid.

Question 79

Excitability and irritability are interchangeable terms in regard to muscle cells.

Question 80

An accumulation of lactic acid in the muscle is the result of an oxygen debt.