Muscular Tissue

Front 1

three types of muscle tissue

Back 1

skeletal
Cardiac
smooth

Front 2

how do skeletal bones attach?

Back 2

direct and indirect

Front 3

functions of skeletal muscles

Back 3

1.produce skeletal mov
2.mantain posture and body position.
3. support soft tissue.
4. guard entrances and exits
5. maintain body temperature

Front 4

each muscle fiber is surrounded by an

Back 4

endomysium

Front 5

bundles of muscle fibers are sheathed by a

Back 5

perimysium

Front 6

entire muscle is covered by an

Back 6

epimysium

Front 7

@ ends of muscle

Back 7

tendons

Front 8

other name 4 tendons

Back 8

aponeuroses

Front 9

tendons attach?

Back 9

muscle to bone

Front 10

where are the blood vessels and nerves located?

Back 10

epimysium and perimysium

Front 11

sarcolema?

Back 11

cell membrane

Front 12

sarcoplasm?

Back 12

cytoplasm

Front 13

sarcoplasmic reticulum?

Back 13

similar to smooth ER

Front 14

part of the skeltal muscle fibers. aid in contraction

Back 14

Transverse (T) tubules and myofibrils

Front 15

filaments in a ycrofibril are organized into rpeating funcrtional units called

Back 15

sarcomeres

Front 16

form myofribrils (2) (kins of myofilaments)

Back 16

thin filaments and thick filaments

Front 17

thin filaments and thick filaments make up

Back 17

myofilaments

Front 18

thin filaments consist of

Back 18

F actin
Nebulin
Tropomyosin
Troponin

Front 19

tropomyosin molecules cover active sites on

Back 19

G actin.

Front 20

G actin units form

Back 20

F actin strands

Front 21

troponin bind to both

Back 21

G actin and tropomyosin

Front 22

what protein holds tropomyosin in position

Back 22

Troponin

Front 23

Thick filaments consist of a bundle of

Back 23

myosin molecules around a titin core.

Front 24

composition of a myosin molecule

Back 24

elongated tail and globular head

Front 25

formatiton of cross bridges occurs during....

Back 25

contraction

Front 26

in a resting molecule tropomyosin prevents

Back 26

the attachment of myosin heads to active sites on g actin

Front 27

the activity of a muscle fiber is crlted by a neuron at a

Back 27

Neuromuscular junction (NMJ)

Front 28

when an action potential arrives at the synaptic terminal, acetylcholine (Ach) is released into....

Back 28

the synaptic cleft

Front 29

how is the action potential in the sarcolema generated

Back 29

the binding of Ach to receptors on the opposing junctional folds

Front 30

When does excitation contraction occur?

Back 30

as the passing of an action potential along a t tubule triggers the release of Ca+

Front 31

During excitation- contraction coupling Ca+2 is released from

Back 31

the cisternae of the SR at triads

Front 32

What does the release of Ca+ initiates

Back 32

a contraction cycle of attachment, pivoting detachment and return.

Front 33

where does the calcium ions bind?

Back 33

troponin

Front 34

What happens when Ca+ binds top troponin?

Back 34

troponin changes position and moves tropomyosin away from the active site of actin

Front 35

once the active site in g actin are exposed ...what can now bind to actin?

Back 35

Cross bridges of myosin heads

Front 36

What action does the myosin molecule engage in once it is bound to actin

Back 36

each myosin head pivots at its base pulling the actin filament towards the center of the sarcomere

Front 37

name the enzyme that breaks don ACh and limits the duration of muscle stimulation

Back 37

Acetylcholinesterase (AchE)

Front 38

What happens during relaxation?

Back 38

AchE breaks down Ach

Front 39

What is the amount of tension produced by a muscle fiber dependent on

Back 39

on the number of cross bridges formed

Front 40

how is Ach released

Back 40

via exocytosis

Front 41

an action potential travels the length of???

Back 41

the axon of a motor neuron to an axon terminal

Front 42

What is the NMJ

Back 42

consist of the points of contact between the axon terminal of the motor neuron and the motor end plate of the skeletal muscle fiber

Front 43

How do calcium ions diffuse into the terminal?

Back 43

Voltage gated Ca channels

Front 44

entry of Ca+ caused _______to release ach

Back 44

synaptic vesicles

Front 45

where does Ach go once it os exocytosed out of the synaptic vessicles

Back 45

Ach diffuses across the synaptic cleft and bind to ach receptors

Front 46

How does Ach bind to Ac receptors

Back 46

ach receptors contain ligan gated cation channels that open when Ach binds

Front 47

once the ligand gated cation channels are open (opened by Ach) what exchange occurs?

Back 47

Na+ enter muscle fiber
K exit muscle fiber

Front 48

why does the membrane potential become increasingly more negative?

Back 48

due to more Na+ entering relative to the entrance of K-

Front 49

At what point does the action potential propagate along the sarcolema?

Back 49

once it has reached the threshold value

Front 50

When does neural transmission to a muscle fiber cease ?

Back 50

when Ach is realeased form synaptic cleft

Front 51

How is Ach released ?

Back 51

Ach diffuses away from the synapse and then brochen down by achE to acetic acid and choline

Front 52

Where is choline transported to?

Back 52

into the axon terminal for the resynthesis of ach

Front 53

when can skeletal muscle fibers contract most forcefully ?

Back 53

when stimulated over a narrow range of resting lengths.

Front 54

a twitch is a .....?

Back 54

a cycle of contraction and relaxation produced by a single stimulus

Front 55

Repeated stimulation at slow rate produces

Back 55

treppe

Front 56

Treppe?

Back 56

progressive increase in twitch tension
Staircase phenomenon

Front 57

repeated stimulation b4 the relaxation phase ends may produce

Back 57

summation of twitches (wave summation)

Front 58

wave summation

Back 58

where one twitch is added to another

Front 59

incomplete tetanus

Back 59

tension peaks because the muscle is never allowed to relax completelly

Front 60

complete tetanus

Back 60

relaxation phase is eliminated

Front 61

what determines how precisely controlled mov are.

Back 61

the number and size of a muscle motor units

Front 62

what stabilizes bones and joints

Back 62

muscle tone

Front 63

isotonic contractions

Back 63

tension in a muscle rises and the length of the muscle changes

Front 64

isometric contractions

Back 64

tension rises but the length of the muscle remains constant.

Front 65

relationship between resistance (load) and speed of contraction

Back 65

inversely related

Front 66

return to resting length after contraction may involve

Back 66

elastic forces / the contraction of opposing muscle groups / and gravity.

Front 67

Creatine phosphate (CP) ca release

Back 67

stored energy to convert ADP to ATP

Front 68

provides most of the ATP needed to support muscle contraction

Back 68

aerobic metabolism (@ rest or at moderate levels of activity.

Front 69

cells use anaerobic process of glycolysis to generate ATp when

Back 69

peak levels of activity

Front 70

a fatigued muscle can no longer contract coz????

Back 70

changes in ph due to buildup of lactic acid. , exhaustion of energy resources etc

Front 71

oxygen debt

Back 71

excess post exercise oxygen consumption (EPOC)

Front 72

EPOC

Back 72

amount of oxygen requerid during the recovery period to restore the muscle to its normal condition.

Front 73

the 3 types of skeletal muscle fibers are

Back 73

fast fibers
Slow fibers
Intermediate fibers

Front 74

Fast fibers contain

Back 74

densely packed myofibrils and are large in diameter.
Large glycogen reserves.
and relatively few mitochondria

Front 75

describe the contractions of fast fibers

Back 75

rapid and powerful of brief duration

Front 76

slow fibers

Back 76

half the diameter of fast fibers and take 3 times as long to contract after stimulation

Front 77

specializations of slow fibers ( continue contracting for an extended period of time)

Back 77

abundant mitochondria, extensive capillary supply, high concentrations of myoglobin

Front 78

myoglobin

Back 78

an oxygen binding pigment specially common in slow skeletal muscle fibers and cardiac muscle cells

Front 79

intermediate fibers are similar to fast fibers but

Back 79

have a greater resistance to fatigue.

Front 80

white muscles.

Back 80

dominated by fast fibers
Appear pale.

Front 81

red muscles

Back 81

dominated by slow fibers and are rich in myoglobin

Front 82

hypertrophy

Back 82

enlargement of the stimulated muscle (while training to develop anaerobic endurance)

Front 83

anaerobic endurance

Back 83

time over witch muscular contractions can be sustained by glycolysis and reserves and ATP and CP

Front 84

aerobic endurance

Back 84

time over witch a muscle can continue to contract while supported by mitochondrial activities

Front 85

size of cardiac muscle cells

Back 85

small
have broad t tubules

Front 86

nucleus of cardiac muscle cells

Back 86

centrally located

Front 87

cardiac muscle cells are dependent on

Back 87

aerobic metabolism

Front 88

intercalated discs are found?

Back 88

where cell membranes connect

Front 89

Automaticity

Back 89

Cardiac muscle cells contract with out neural stimulation and contractions last longer than skeletal muscle

Front 90

why cant cardicac muscle produce tetanic contractions

Back 90

because the twitches do not exibit wave summation

Front 91

characteristics of smooth muscle tissue

Back 91

nonstriated
lack sarcomeres
involuntary muslce tissue

Front 92

on smooth muscle tissue thin filaments are anchored to....

Back 92

dense bodies

Front 93

what triggers the contraction of smooth muscle

Back 93

when calcium ions interact with calmodulin

Front 94

what activates myosin light chain kinase

Back 94

the interaction of calcium ions with calmodulin

Front 95

plasticity

Back 95

smooth muscle works over a large range of lengths

Front 96

how do cells in a multiunit smooth muscle cell act

Back 96

relatively independent form others in the organ

Front 97

visceral smooth muscle cells are not always

Back 97

inervated by motor neurons

Front 98

neurons that innervate smooth muscle cells are not under

Back 98

voluntary control

Front 99

why does skeletal muscle appear striated when viewed through a microscope

Back 99

because z lines and thick filaments of the myofibrils within the muscle fibers are aligned

Front 100

where would u expect the grater concentration of calcium ions

Back 100

in the cisternae of the SR in resting skeletal muscle.

Front 101

what drug would interfere with muscle contraction

Back 101

one that interferes with cross bridge contraction between the myosin and actin myofilaments

Front 102

amount of cross bridge formation is proportional to

Back 102

amount of available calcium ions

Front 103

increased permeability to the sarcolema to ca+2 leads to

Back 103

an increased intracellular concentration of calcium and a greater degree of contraction

Front 104

other consecuences of an increase in permeability to ca+2 ions

Back 104

muscle wont be able to relax completely coz the amount of ca ions in the sarcolema must be decreased

Front 105

what would happens if there was no acE??/

Back 105

the motor end plate would be continuously stimulated by Ach . the muscle would lock in a state of cotnraction.

Front 106

what happens in a muscle that is overstretched

Back 106

the myofilaments would overlap very little. very few cross bridges would for. weak contraction.

Front 107

during treppe. why does tension in a muscle gradually increase. (strength and frequency of the stimulus are constant)

Back 107

not enough time between successive contractions to reabsorb all the ca ions . higher levels in sarcoplasm. allowing more cross bridges to form and tension to increase.

Front 108

concentric

Back 108

shorten

Front 109

eccentric

Back 109

elongate

Front 110

what function of the cardiac muscle tissue allows the heart to act as a functional syncytium?

Back 110

joined by gap junctions.
All cells contract simultaneously as if they were a single unit. (syncytium)

Front 111

gap junctions

Back 111

allow ions and small molecules to flow directly form one cell to another.
Action potentials that are generated in one cell can spread rapidly to adjacent cells

Front 112

cardiac and smooth muscle contractions are more affected by changes in extracellular Ca+ than skeletal/??

Back 112

coz most of the ca come from the extracellular fluid. in skeletal they come from SR

Front 113

smooth muscle can contract over a wider range of resting lengths ????

Back 113

actin and myosin molecules filaments are not as rigidly organized as skeletal.

Front 114

connective tissue coverings of a skeletal muscles (in order)

Back 114

epimysium, perimysium, endomysim

Front 115

the command to contract is distributed deep into the muscle fiber by the

Back 115

t tubules