A & P Ch. 8 - Muscle Physiology

Front 1

Location

Back 1

Skeletal muscle - attached to skeleton
Smooth muscle - walls of intestines, blood vessels, etc.
Cardiac muscle - walls of heart

Front 2

Control

Back 2

Skeletal muscle - voluntary
Smooth muscle - involuntary
Cardiac muscle - involuntary

Front 3

Shape of fibers

Back 3

Skeletal muscle - elongated, cylindrical, blunt ends
Smooth muscle - elongated, spindle shaped, pointed ends
Cardiac muscle - elongated, cylindrical fibers that brance

Front 4

Striations

Back 4

Skeletal muscle - present
Smooth muscle - absent
Cardiac muscle - present

Front 5

#nuclei per fiber

Back 5

Skeletal muscle - many
Smooth muscle - one
Cardiac muscle - one or two

Front 6

Position of nuclei in cell

Back 6

Skeletal muscle - peripheral
Smooth muscle - central
Cardiac muscle - central

Front 7

Speed of contraction

Back 7

Skeletal muscle - most rapid
Smooth muscle - slowest
Cardiac muscle - intermediate

Front 8

Ability to remain contracted

Back 8

Skeletal muscle - least
Smooth muscle - greatest
Cardiac muscle - intermediate

Front 9

Muscle fiber/muscle cell

Back 9

Structural unit of the muscle tissue
Has elongated shape

Front 10

Smooth (unstriated) muscle

Back 10

mass of individual spindle-shaped contractile cells
Walls of digestive tract and uterus, linings of blood vessels, certain ducts

Front 11

Cardiac muscle

Back 11

more organization ofthe contracting proteins than in smooth muscle cells

Front 12

Striated muscle/skeletal muscle

Back 12

each muscle cell is a fused set of dozens or hundreds of cells
very long, also called muscle fibers
Ability to exert force in one direction

Front 13

Muscle cells contraction

Back 13

contract by active mechanism - when stimulation is provided
relax by passive mechanism

Front 14

antagonistic muscles

Back 14

muscles that move body parts in different directions
i.e. flexor and extensor muscles

Front 15

Endomysium

Back 15

connective tissue that wraps individual muscle fibers

Front 16

Perimysium

Back 16

wraps bundles of muscle fibers

Front 17

fasicles

Back 17

bundles of muscle fibers

Front 18

epimysium and fascia

Back 18

enclose the entire muscle

Front 19

Superficial fascia

Back 19

contains much fat in obese individuals

Front 20

Gaster

Back 20

portion of the muscle with fibers

Front 21

voluntary control of muscle

Back 21

contracts only when stimulated by neurons that deliver nerve impulses to it

Front 22

myofibrils

Back 22

4 - 20 rod-like filaments in each fiber

Front 23

Sacroplasm/cytoplasm

Back 23

bathes the myofibrils

Front 24

Mitochondria

Back 24

scattered throughout the sacroplasm
provide ATP as an energy source for the contraction of myofibrils

Front 25

sacromeres

Back 25

smaller units along the length of myofibrils
each about 2 micrometers in length
Functional unit of skeletal muscle
Gives muscle striated pattern

Front 26

Thin filaments

Back 26

one of 2 types of myofilaments which compose sarcomere
Run parallel to one another

made of protein actin

Front 27

Thick filaments

Back 27

one of 2 types of myofilaments which compose sarcomere

Made of protein myosin

Front 28

Z line

Back 28

The point where actin filaments from adjacent sarcomeres interweave in a line
Bisects relatively clear broad strip called the I band

Front 29

I band

Back 29

Broad stripe on sarcomere bisected by Z line

Front 30

A band

Back 30

Dense stripe in the center of the sarcomere formed by overlapping myosin filaments

Front 31

H Zone

Back 31

Bisects A band
contains myosin filaments but no actin filaments

Front 32

Striated muscle

Back 32

formed by repeating A and I bands in the myofibrils

Front 33

Sliding filament model

Back 33

myosin heads act as crossbridges between actin and myosin filaments

Front 34

Power stroke

Back 34

pulls actin filaments inward toward the H zone
sliding shortens the sarcomeres
muscle shortens and contracts

Front 35

Adenosine Triphosphate (ATP)

Back 35

broken down by enzymes into ADP
bginds to enzyme on myosin head
ATP molecule is cleaved, ADP and phosphate remain bound to the head.

Front 36

Red muscle/oxydative muscle (slow)

Back 36

large quantity of reddish molecul myoglobin, where oxygen is stored

Front 37

White muscle / glycolytic muscle (fast muscle)

Back 37

plentiful glycogen
little or no myoglobin, stores little oxygen. ATP is used up quickly and cannot be replaced rapidly. Becomes fatigued with build up of lactic acid.

Front 38

Tropomyosin

Back 38

molecules of a protein in the grooves of the actin helix

When muscle is at rest, prevents myosin heads from binding to actin by masking the site where binding would ordinarily occur

Front 39

Troponin

Back 39

protein found at regular intervals along the actin filament
Binds to both tropomyosin molecules and actin molecules
Binds to calcium ions

Front 40

Acetylcholine

Back 40

neurotransmitter released when nerve impulses reach the muscle fiber at the neuromuscular junction

Front 41

Neurmuscular junction

Back 41

consists of a single muscle fiber and the terminal end of a single nerve cell.
Nerve and muscle cells are close, but don't touch remain separated by synapse

Front 42

Synapse

Back 42

space between nerve and muscle cells

Front 43

Sodium ions

Back 43

in resting cells, concentration is kept low by active transport

Front 44

Sarcolemma of muscle fiber

Back 44

plasma membrane of muscle fiber where sodium ions rush in when acetylcholine binds receptors

Front 45

Calcium ions

Back 45

concentration in the cytoplasm of resting muscle is low because it is pumped out of the cell or into the cells specialized endoplasmic reticulum or sarcoplasmic reticulum

Front 46

Transverse tubules / T tubules

Back 46

system of infoldings of teh plasma membrane or sacrolemma

Front 47

All-or-nothing response

Back 47

Fiber contracts only after an impulse exceeds a certain threshold and spreads through the cell.

Front 48

Graded response to stimulus

Back 48

Entire muscles do not have all or nothing response
Response is graded depending on number of contracting fibers in a muscle.

Front 49

Motor unit

Back 49

Muscle fibers and the neuron that stimulates them

Front 50

Twitch

Back 50

contraction of amuscle fiber

Front 51

Sumation

Back 51

increasing number of twitches occurring in a muscle due to continued stimulation

Front 52

Tetanus

Back 52

a state of sustained maximum contraction
i.e. making a fist

Front 53

Tonus

Back 53

muscle tone - a condition in which a muscle is kept partially contracted over a long period of time
One set of fibers, then another set is briefly stimulated so some of the muscle is always contracted

Front 54

Normal posture

Back 54

achieved by tonus

Front 55

Creatine phosphate

Back 55

one of the sources for regenerating ATP
contains high energy phosphate bonds
storage depot for cellular energy

Front 56

Anerobic reactions of glycosis

Back 56

glucose molecules are converted through multiple steps into pyruvic acid molecules

Front 57

Lactic acid

Back 57

if cell's oxygen is depleated pyruvic acid is converted into lactic acid
causes pH changes and muscle fibers respond poorly to stimulation

Front 58

Oxygen debt

Back 58

occurs as lactic acid accumulates. Oxygen must be supplied to prevent further buildup of lactic acid

Front 59

Smooth muscle

Back 59

slender, elongated, spindle shaped cells without striations and with a single nucleus

Front 60

Gap junctions

Back 60

link some smooth muscle cells together

Front 61

Visceral muscle

Back 61

another name for smooth muscle
found in visceral organs
no sarcomeres
Thin and thick filaments are collected into bundles

Front 62

Dense bodies

Back 62

permit attachment of thin filaments in smooth muscle
Counterparts to Z lines in skeletal muscles

Front 63

Single unit smooth muscle

Back 63

visceral muscle whose fibers contract together as a rhythmic unit, and are coupled by one another by gap junctions

Front 64

Multi unit smooth muscle

Back 64

Lines the airways to the lungs and the large arteries and the erector pili muscles of the hair follicles.
Fibers work independently of one another - gap junctions rare

Front 65

Intercalated discs

Back 65

Binds ends of cardiac muscle together
Many gap junctions- electrical current flows easily.

Front 66

The type of muscle found in the walls of the digestive tract is the

Back 66

smooth muscle

Front 67

Heart muscle is also known as

Back 67

cardiac muscle

Front 68

The most abundant type of muscle in the human body is a striated muscle, also known as

Back 68

skeletal muscle

Front 69

Muscles that work against each other are said to be

Back 69

antagonistic muscles

Front 70

The submicroscopic filaments of a muscle cell are known as

Back 70

myofibrils

Front 71

The functional unit of muscle activity is correctly known as the

Back 71

sarcomere

Front 72

The thick filaments in the central portion of the sarcomere are composed of the protein

Back 72

myosin

Front 73

The thin filaments of a sarcomere are composed of the protein

Back 73

actin

Front 74

The thin filaments of a sarcomere in a skeletal muscle fiber are anchored to the

Back 74

Z line

Front 75

The theory that explains the contraction of muscle fibers is called the

Back 75

sliding filament theory

Front 76

During muscle contractions, the thick filaments pull on the thin filaments attached to the Z lines and shorten the

Back 76

sarcomere

Front 77

The primary source of energy for muscle contraction is

Back 77

ATP

Front 78

Red muscle has much oxygen stored in a red-pigmented molecule called

Back 78

myoglobin

Front 79

The continual contractions of muscle fibers require a supply of the energy molecule

Back 79

ATP

Front 80

White muscle is so named because it has little or no

Back 80

myoglobin

Front 81

White muscle is not able to store much

Back 81

oxygen

Front 82

White muscle uses stored glycogen for energy, and is sometimes called

Back 82

glycolytic muscle

Front 83

When a muscle is at rest, myosin heads are prevented from binding to actin by a protein called

Back 83

tropomyosin

Front 84

Muscles are triggered to contract following release of the neurotransmitter

Back 84

acetylcholine

Front 85

The first ion utilized during muscle contraction is

Back 85

sodium

Front 86

Calcium ions are stored in muscle cells within infoldings of the plasma membrane called

Back 86

transverse tubules

Front 87

Following their release, calcium ions trigger muscle contractions by binding to the molecule

Back 87

troponin

Front 88

The binding of calcium to troponin causes a shift in the molecule

Back 88

tropomyosin

Front 89

The shift of position of tropomyosin unmasks the sites on actin filaments that bind to the heads of

Back 89

myosin

Front 90

Muscle contractions come to an end when tropomysin covers the myosin-binding sites on

Back 90

actin

Front 91

Energy is used during muscle contraction to move calcium ions into the sarcoplasmic reticulum and the

Back 91

T tubules

Front 92

The state of continual muscle contraction following death is called

Back 92

rigor mortis

Front 93

Muscle contracts after its threshold has been reached, and the response is called the

Back 93

all-or-nothing response

Front 94

The variable response displayed by a muscle fiber is known as the

Back 94

graded response

Front 95

The number of muscle fibers contracting in a muscle depends on the stimulation from

Back 95

nerve impulses

Front 96

The contraction of a muscle fiber is known as a

Back 96

twitch

Front 97

All the muscle fibers stimulated by one motor neuron constitute a

Back 97

motor unit

Front 98

The increasing number of twitches occurring with continued muscle

Back 98

summation

Front 99

A state of sustained maximum contraction of a muscle is a phenomenon called

Back 99

tetanus

Front 100

The condition in whih a muscle is kept partially contracted over a long period of time is called

Back 100

tonus

Front 101

When ATP is broken down in muscle cells, the two end products are phosphate groups and

Back 101

ADP

Front 102

One source for regernerating ATP is the high-energy molecule

Back 102

creatine phosphate

Front 103

In order for the most energy to be released from carbohydrate molecules in muscle cell metabolism, an essential gas is

Back 103

oxygen

Front 104

When muscle is oxygen-depleted, the energy for muscle contraction is derived from an anaerobic process called

Back 104

glycolysis

Front 105

Extreme muscle fatigue is generally due to teh buildup of an acid called

Back 105

lactic acid

Front 106

Energy is used during muscle contraction to move calcium ions into the sarcoplasmic reticulum and the

Back 106

T tubules

Front 107

The state of continual muscle contraction following death is called

Back 107

rigor mortis

Front 108

Muscle contracts after its threshold has been reached, and the response is called the

Back 108

all-or-nothing response

Front 109

The variable response displayed by a muscle fiber is known as the

Back 109

graded response

Front 110

The number of muscle fibers contracting in a muscle depends on the stimulation from

Back 110

nerve impulses

Front 111

The contraction of a muscle fiber is known as a

Back 111

twitch

Front 112

All the muscle fibers stimulated by one motor neuron constitute a

Back 112

motor unit

Front 113

The increasing number of twitches occurring with continued muscle

Back 113

summation

Front 114

A state of sustained maximum contraction of a muscle is a phenomenon called

Back 114

tetanus

Front 115

The condition in which a muscle is kept partially contracted over a long period of time is called

Back 115

tonus

Front 116

When ATP is broken down in muscle cells, the two end products are phosphate groups and

Back 116

ADP

Front 117

One source for regenerating ATP is the high-energy molecule

Back 117

creatine phosphate

Front 118

In order for the most energy to be released from carbohydrate molecules in muscle cell metabolism, an essential gas is

Back 118

oxygen

Front 119

When muscle is oxygen-depleted, the energy for muscle contraction is derived from an anaerobic process called

Back 119

glycolysis

Front 120

Extreme muscle fatigue is generally due to the buildup of an acid called

Back 120

lactic acid

Front 121

Following strenuous activity, a person breathes deeply to repay an

Back 121

oxygen debt

Front 122

Much of the lactic acid produced during strenuous muscle activity is carried from the muscle cells for metabolism by the

Back 122

liver

Front 123

Where contractions of the skeletal muscles are fast, the contractions of smooth muscles are generally

Back 123

slow

Front 124

Smooth muscle is so named because it contains no

Back 124

stiations

Front 125

The muscle cells between some smooth muscles are linked together by junctions known as

Back 125

gap junctions

Front 126

Where skeletal muscles are voluntary muscles, the smooth muscles are

Back 126

involuntary

Front 127

Because smooth muscle is found in the internal organs, it is sometimes called

Back 127

visceral muscle

Front 128

Cardiac muscle is striated, and it is liberally supplied by energy yielding organelles called

Back 128

mitochondria

Front 129

The ends of cardiac muscle cells are connected to one another by gap junctions in

Back 129

intercalated disks

Front 130

Cardiac muscle is similar to smooth muscle because it is not under

Back 130

voluntary control

Front 131

Smooth muscle may be found in the

Back 131

digestive tract

Front 132

The two proteins of the myofibrils are

Back 132

actin and myosin

Front 133

The Z line, I band, A band, and H zone are all anatomical parts of the

Back 133

sarcomere

Front 134

For the successful completion of a muscle contraction, the sarcoplasmic reticulum

Back 134

ATP,l which breaks down and releases energy

Front 135

During muscle contraction, calcium ions bind to sites

Back 135

on troponin molecules