Muscle Cells (Cell Bio Test #1)

Front 1

Skeletal muscle are for ________ movements

Back 1

Voluntary quick

Front 2

Skeletal cells are Multi/uni nucleated

Back 2

Multinucleated with nuclei below the sarcoma

Front 3

Skeletal cells develop embryonically from _____ and differentiate into ______

Back 3

Mesemchymal cells; myoblasts

Front 4

Myoblasts fuse together to form _____

Back 4

Myotubes

Front 5

After ____ dveelop the myotubes become myofibers

Back 5

myofibrils

Front 6

Define: Satellite cells

Back 6

Undiofferentiated stem cells between plasma membrane and external lamin that have potential to differentiate into myoblasts following injury

Front 7

What happens with an increase in exercise?

Back 7

Satellite cells divide and one daughter cell fuses with existing muscles to calse hypertrophic increase in muscles

Front 8

A bundle of muscle fibers is called a

Back 8

Myofibril

Front 9

Structure of skeltal muscle fiber

Back 9

Logitudinally oriented bundles of actin and myosin filaments

Front 10

Sarcomere

Back 10

Unit of contraction of muscles

Front 11

I band

Back 11

Light staining band

Front 12

A band

Back 12

Dark staining band contains H band and M band

Front 13

Thin filaments ared composed of ______ and only present in the ____ band

Back 13

Actin; I band

Front 14

Thick filaments are composed of _____ and make up the bulk of the _____ band

Back 14

Myosin II; A band

Front 15

Contraction mechanism

Back 15

Sarcomertes shorten and Z lines are brought together

Front 16

Stretching mechanism

Back 16

Z lines brought further away from eachother

Front 17

Thin filaments

Back 17

Composed of Actin

Front 18

Regulatory proteins attached to Actin

Back 18

Tropomyosin and Troponin

Front 19

Troponin is important in _________

Back 19

muscle contraction

Front 20

Thick filaments composed of

Back 20

Myosin II

Front 21

Structure of myosin II

Back 21

Two heavy chains and four light chains

Front 22

Structure of thick filaments

Back 22

Mysoin heads oriented away from center of the filament

Front 23

Accesory proteins

Back 23

Maintain the position of the thin and thick filaments

Front 24

Function of alpha actinin

Back 24

Contained in thin filaments and anchors them to the Z line

Front 25

Function of nebulin

Back 25

Wraps around each filaments to maintain length and georgraphic arrangement of thin filament; attaches to the z line and regulates number of G actin monomers

Front 26

Function of tropmodulin

Back 26

caps the free end of ecah filament; regulates the length of think filaments within each sarcomere

Front 27

Function of titin

Back 27

Maintains A band position during contracting and relaxation in thick filaments by attaching thick filaments to the Z line

Front 28

Function of desmin

Back 28

forms lattice level at teh Z line links adjacent myofibrils to eachother

Front 29

Function of dystrophin

Back 29

Links laminin to cytoskeletal actin actin filaments

Front 30

Duchenes Musuclar systriphy

Back 30

Absence of dystrophon and muscles become weaker

Front 31

What is needed for contraction?

Back 31

ATP and calcium

Front 32

Mysoin cannot interact with actin when a muscle is at rest because_______

Back 32

Tropomyosin blocks actin binding site

Front 33

Calcium binds to _______ causing ______

Back 33

troponin; a comformational change dislodging tropomyosin

Front 34

Rigor configuration

Back 34

Myosin binds tightly to the exposed actin binding site

Front 35

Myosin has a binding site for _____

Back 35

ATP

Front 36

ATP binds and induces conformation changes resulting in ________

Back 36

detatchment of myosin heads from actin binding sites

Front 37

_____ enzyme activity is residnet within the mysoin heads

Back 37

ATPase

Front 38

ATP is hydrolyzed to _____ and the myosin head bends towards ________ line

Back 38

ADP + P; Z line

Front 39

Crossbridge

Back 39

Tightness that results in binding of actin to myosin when Pi is released

Front 40

Define: Power stroke

The ADP molecule _____

Back 40

Myosin returns from unbent position swinging and pulling forward of thin filaments toward the center of the sarcomere
Drops off

Front 41

Skeletal muscle is controlled by nerve impulses to muscle fibers via

Back 41

Motor end plates

Front 42

Define motor end plate (neuromuscual junction)

Back 42

Specilaezd synaptic areas on the sarcolema

Front 43

Motor unit

Back 43

One axon can innervate one or more muscle fibers

Front 44

Primary synaptoc cleft

Back 44

Where motor endplate is located

Front 45

Secondary synaptic cleft

Back 45

Sarcolema further folded into smaller ridges

Front 46

Aetycholine

Back 46

Binds to receptors on sarcolema; resultsing in increased permeability of sarcolema to sodium

Front 47

Acetycholineseterase

Back 47

an enzyme that breaks down acetylcholine when action potential is finsihed (located in sarcolema)

Front 48

Myesthenoa gravis

Back 48

autoimmune disease in which Acetycholine receptors are destroyed resulting in progressive muscle weaknesses

Front 49

Transverse (T) tubules

Back 49

Located at A-I junction of a sarcomeres; receives wave of depolarization

Front 50

Depolarization is conducted to the ______

Back 50

Sarcoplasm reticulum

Front 51

Terminal cisternae

Back 51

Expanded portions of the sarcoplasm reticulum; present on each side of the T tubule and form a triad

Front 52

Triad

Back 52

Formed by terminal cisternae on each side of the T-Tubule

Front 53

Junctional channel complex

Back 53

Voltage sensors that stimulate release of calcium from the terminal cisternae

Front 54

Calsequestrin

Back 54

Calcium binding protein

Front 55

Muscle spindles

Back 55

Sensory receptoirs that transmit information to the CNS about the degree of stretch

Front 56

Two types of spindle fibers

Back 56

Nuclear bag fibers; nuclear chain fibers

Front 57

Afferent nerve fibers

Back 57

Nerve fibers that wrap around spindle cells and activate sensory fibers

Front 58

Aplha motor neuron

Back 58

innervate spindle cells to regulate sensitivity of the muscle spindles

Front 59

Three types of skeletal msucle fibers

Back 59

Red, white, intermediate

Front 60

Red fiber structure

Back 60

Rich supply of capillaries, high content of red pigments and mitochondria

Front 61

Red fiber function

Back 61

Slow sustained contraction, located in limbs and the back

Front 62

Myoglobin

Back 62

Binds oxygen and facilitates movement of myuscle within cell

Front 63

White fiber structure

Back 63

Fewer capillaries, fewer mitchochondria, low myoglobin

Front 64

White fibers action

Back 64

rapid contraction that generates a large force , digits of the fingers, extraocular muscles

Front 65

Intermediate muscles

Back 65

Fast twitch and fatigue resistant

Front 66

Cardiac muscle is ______ contraction

Back 66

involuntary

Front 67

Cardai muscle are surrounded by

Back 67

endomycium ONLY

Front 68

Structure of cardiac muscle

Back 68

BRANCHING fibers, 1 CENTRALLY located nucles, smaller individual cells than skeletal muscle fibers but longer

Front 69

Functional syncytium

Back 69

Melding togethr of cells

Front 70

Intercalcalated Discs

Back 70

Junctional specialization that cpmmect fobers to the end

Front 71

Three junctions present

Back 71

Desmosomes, fascia adherens, gap junctions

Front 72

Function of desmosomes and fascia adherens

Back 72

Maintain string cell cohesion and transmit pull of one contractile unit to the next along teh axis of fibers

Front 73

Gap junctions

Back 73

Allow for spread of polarization signal froim one cardiac muscle cell to the next

Front 74

T-tubules in cardiac muscle invaginate at ______

Back 74

Z line not the A-I junction like they do in skeletal muscle

Front 75

Other difference in cardiac muslce contraction

Back 75

No triads (there are diads) and no terminal cisternae or terminal end plates

Front 76

Purkinje myocites

Back 76

Pacemakeers

Front 77

Sinoatrial and AV node

Back 77

Main pacemakers/location of pacemakers myocites

Front 78

Structure of Purkinje myocites

Back 78

Modified cardiac myocites located beneath endocardial surface; abundant glycogen granules, less obvious intercalated discs; conduct depolarization

Front 79

Pacemaker myocites are infulenced by ______ fibers

Back 79

symoathetic and parasympatheic (slows down) fibers

Front 80

Purkinje are ___ staining

Back 80

Pale

Front 81

Myocardial endocrine cells in atrium contain

Back 81

dark staining granules which are precursors for atrial natriuretic polypeptides

Front 82

Function of Atrial Natruiretic Polypetides

Back 82

Cause vasodilation and diuresis resulting in lowered blood pressure and decreased blood vessles

Front 83

Smooth muscle characteristics

Back 83

No sarcomeres, one centrally located nucleus, smaller cells, actin and mysoin much less formally arranged, fusiform( spindle shaoed), surrounded by basal laminae

Front 84

Function of smooth muscle

Back 84

Slow, sustained, involuntary contraction

Front 85

Smooth muscle may be arrange in ______ or _____

Back 85

Sheets (wall of GI tract) or bundles (walls of the uterus)

Front 86

Structure of smooth muscle

Back 86

Thin filamentys, F actin and tropomyosin (NO TROPONIN) distrubuted as network

Front 87

Dense bodies

Back 87

Functional equivalent of Z lines of striated muscle

Front 88

Thick filaments are/are noit seen

Back 88

Are not seen

Front 89

Structure of myosin II in smooth muscle

Back 89

Light chains, folded until phosphorolation occurs

Front 90

Calmoduliin

Back 90

Calcium binds to it and allows calcium/calmoidium chain to occur which then phoshorolates myosin light chain

Front 91

Thick filaments in smooth muslce are ____polar

Back 91

side (myosin heads present all along length of the filament)

Front 92

Alpha actinin

Back 92

Attach F actiin and tropomyosin at the sarcolema

Front 93

Caveolae

Back 93

Vessicles where calcium may be stored

Front 94

Neural stimulation of smooth muscle

Back 94

Occurs via ACH and norepinephrine which diffuse to sarcolema to stimulate receptors on smooth musclke sarciolema activating Ca chanels

Front 95

Chemical stimulation of smooth muscle

Back 95

Vasopressin, angiotensin II acts on specfic membrane receptors

Front 96

Hormones may activate contraction including

Back 96

Estrogen and oxytocin

Front 97

Smooth muscle may be initiated by:

Back 97

Neural stimulation, chemical, hormone, stretch

Front 98

Contraction bands

Back 98

Result from spreading of excitation throughout muscle mass

Front 99

Smooth muscle is the _____ but _______

Back 99

Longest but shortest in diameter

Front 100

Another name for muscle fiber

Back 100

myocyte

Front 101

Cell membrane + endomyseum

Back 101

Sarcolema

Front 102

Another name for cytoplasm

Back 102

sarcoplasm

Front 103

Epimysium

Back 103

Outermost sheath of dense connective tissue; continous with tendon

Front 104

Perimysium

Back 104

This collagenous septa that divides muscle fibers into fasicles

Front 105

Endomysium

Back 105

Newtork of reticular fibers, fibroblasts and basal laminae which invests each muscle in the fasicle