Chapter 17 (Lab) Organization Of Skeletal Muscles

Front 1

locomotion

Back 1

movement of the body

Front 2

excitable

Back 2

nervous tissue and muscle tissue

Front 3

action potential

Back 3

electrical impulses that (in this case) cause contraction

Front 4

extensible

Back 4

muscle tissue can stretch

Front 5

elasticity

Back 5

muscle tissue can recoil back to original shape and size

Front 6

Muscle tissue is

Back 6

elastic
extensible
excitable

Front 7

Epimysium

Back 7

covering of skeletal muscle organ as a whole

Front 8

Perimysium

Back 8

the connective tissue between each muscle fascicle

Front 9

Endomysium

Back 9

the connective tissue between each muscle fiber (cell)

Front 10

sarcolemma

Back 10

cell membrane of a muscle fiber

Front 11

sarcoplasm

Back 11

the cytoplasm of surrounding individual muscle fiber cells

Front 12

T tubules

Back 12

connects sarcolemma to interior of muscle fiber
pass contraction stimuli to deeper regions of muscle fiber

Front 13

myofibrils

Back 13

thousands of rods of proteininside each muscle fiber

Front 14

sarcoplasmic reticulum

Back 14

modified endoplasmic reticulum that stores calcium ions
surrounds each myofibril

Front 15

terminal cisternae

Back 15

large calcium ion sotrage chambers which lie adjacent to transverse tubules

Front 16

triad

Back 16

sandwich made of a t-tubule, plus terminal cisterna on either side

Front 17

Actin

Back 17

THIN filament (3000)

Front 18

Myosin

Back 18

THICK filament (1500)

Front 19

sarcomere

Back 19

repeating patterns of actin and myosin along a myofibril

Front 20

Z line

Back 20

where thin actin connects to one another at the END of a sarcomere

Front 21

Actinin

Back 21

what makes up a Z line

Front 22

I band

Back 22

area newar Z line that contains only thin filaments

Front 23

A band

Back 23

area containing both thin and thick filaments located between I bands in a sarcomere

Front 24

zone of overlap

Back 24

where thick and thin bind during muscle contraction

Front 25

H zone

Back 25

middle region of an A band and contains ONLY THICK filaments

Front 26

Four proteins that make up actin strands

Back 26

G actin
F actin
nebulin
active sites

Front 27

G actin

Back 27

spherical molecules like pearls on a necklace

Front 28

F actin

Back 28

300-400 G actins twist together

Front 29

Nebulin

Back 29

"string of a necklace" that holds beads "g-actins" in place

Front 30

tropomyosin

Back 30

follows twisted actin strands and blocks active sites to regulate muscle contraction

Front 31

troponin

Back 31

holds tropomyosin in position and has binding sites for calcium ions

Front 32

two strands of myosin

Back 32

two intertwined tail regions and two globular head regions

Front 33

titin

Back 33

protein that attaches thick filament to the Z line on end of sarcomere

Front 34

Muscular dystrophies

Back 34

inherited diseases that cause changes in muscle proteins that result in progressive weakening and deterioration of skeletal muscles

Front 35

DMD (Duchenne

Back 35

starts in childhood and fatal with cardiac and respiratory failure by age of 20

mutation of gene for muscle protein dystrophin part of anchoring complex that attaches thin filaments to sarcolemma

calcium channels remain open in absence of dystrophin

located on X chromosome mothers can be carriers and 50% chance to pass on to male offspring

Front 36

motor neuron

Back 36

nerve cell controlling skeletal muscle fiber

Front 37

ACh

Back 37

chemical released by motor neuron

Front 38

Neuromuscular junction/ myoneural junction

Back 38

where motor neuron and muscle fiber meet

Front 39

synaptic vesicles

Back 39

store ACh at end of synaptic knob/terminal

Front 40

Synaptic cleft

Back 40

small gap that separates knob from a folded area of sarcolemma called motor end plate

Front 41

AChE

Back 41

esterase- breaks down ACh to prevent over stimulation of muscle fiber

Front 42

Muscle contraction

Back 42

AP travels down neuron and raches synaptic knob and vesicles release ACh into synaptic cleft. ACh diffuses across cleft and binds to ACh receptors embedded in sarcolemma at motor end plate of muscle fiber. Binding causes sarcolemma to generate an action potential. Spread down T tubules causing calcium ions to be released from sarcoplasmic reticulum into sarcoplasm of muscle fiber. Calcium ions bind to troponin which moves tropomyosin and exposes active sites on G actins. Myosin heads attach at active sites and ratchet thin filaments inward. Thin filaments slide into H zone and sarcomere shorterns