Muscular System - Seeley

Front 1

epimysium

Back 1

connective tissue sheath that surrounds each skeletal muscle

Front 2

muscle fasciculus

Back 2

muscle bundle

Front 3

perimysium

Back 3

connective tissue that surrounds muscle fasciculi

Front 4

muscle fiber

Back 4

single muscle cell; makes up muscle fasciculi

Front 5

endomysium

Back 5

connective tissue that surrounds a muscle fiber

Front 6

myofibril

Back 6

thread-like structure that extends from one end of the muscle fiber to the other

Front 7

actin myofilament

Back 7

thin myofilament which resembles two minute strands of pearls twisted together

Front 8

troponin

Back 8

provide calcium binding sites on actin myofilaments

Front 9

tropomyosin

Back 9

covers and uncovers attachment sites for myosin on actin myofilaments

Front 10

myosin myofilament

Back 10

thick myofilamnets which resemble bundles of golf clubs

Front 11

contractility

Back 11

ability to shorten with a force

Front 12

excitability

Back 12

the capacity to respond to a stimulus

Front 13

extensibility

Back 13

ability to be stretched

Front 14

elasticity

Back 14

ability to recoil to original resting length after being stretched

Front 15

sarcomere

Back 15

the basic structural and functional unit of the muscle

Front 16

z disk

Back 16

forms an attachment site for actin myofilaments; the end of the sarcomere

Front 17

i band

Back 17

part of a myofibril that contains only actin myofilaments

Front 18

a band

Back 18

part of a myofibril where actin and myosin myofilaments overlap

Front 19

h zone

Back 19

part of a myofibril that contains only myosin myofilaments

Front 20

m line

Back 20

anchors the myosin myofibrils in the center of the sarcomere

Front 21

sarcoplasm

Back 21

the cytoplasm of a muscle fiber

Front 22

sarcolemma

Back 22

the cell membrane of a muscle fiber

Front 23

t tubules

Back 23

invaginations of the sarcolemma that wrap around sarcomeres

Front 24

sarcoplasmic reticulum

Back 24

highly organized, smooth endoplasmic reticulum; contains high concentrations of calcium

Front 25

t tubules

Back 25

connect the sarcolemma and the sarcoplasmic reticulum

Front 26

motor neuron

Back 26

nerve cell that carries action potentials to skeletal muscle fibers

Front 27

neuromuscular junction

Back 27

point where the axon of a motor neuron joins with a skeletal muscle fiber; an example of synapse

Front 28

motor unit

Back 28

motor neuron and all the skeletal muscle fibers it supplies

Front 29

synaptic cleft

Back 29

space between the presynaptic terminal and the muscle fiber membrane

Front 30

acetycholine

Back 30

neurotransmitter released from synaptic vesicles of the presynaptic terminal

Front 31

acetycholinesterase

Back 31

enzyme that breaks down acetycholine

Front 32

creatine phosphate

Back 32

molecule used to store energy; used to quickly produce ATP

Front 33

isometric

Back 33

the length of the muscle does not change, but the amount of tension increases during the contraction process

Front 34

isotonic

Back 34

the amount of tension produced by the muscle is constant, but the length decreases

Front 35

eccentric

Back 35

isotonic contractions in which tension is maintained, but the opposing resistance causes the muscle to lengthen

Front 36

concentric

Back 36

isotonic contractions in which muscle tension increases as the muscle shortens

Front 37

tendon

Back 37

general term for the attachment of a muscle to a bone

Front 38

aponeurosis

Back 38

a broad, sheetlike tendon

Front 39

origin

Back 39

the most stationary end of a muscle; the head

Front 40

insertion

Back 40

end of the muscle attached to the bone undergoing the greatest movement

Front 41

belly

Back 41

part of the muscle between the origin and insertion

Front 42

synergists

Back 42

muscles that work together to accomplish a movement

Front 43

antagonist

Back 43

muscle working in opposition to another muscle

Front 44

prime mover

Back 44

muscle that plays the major role in accomplishing a particular movement

Front 45

fixator

Back 45

muscle that holds a bone in place