Lecture 4

Front 1

contraction

Back 1

muscles get shorter some of the time and its a binding of actin and myosin filaments

Front 2

orgin (poximal attachment)

Back 2

proximal point of attachment(usually doesnt move)

Front 3

insertion (distal attachment)

Back 3

distal point of attachment (normally moves)

Front 4

tendons

Back 4

bundles of collagen fibers with little intercellular matrix

Front 5

peritendineum

Back 5

connective tissue membrane that sourrounds the tendons

Front 6

aponeuroses

Back 6

flattened expanded tendons

Front 7

myofilaments

Back 7

basic unit of muscle structure

Front 8

sarcomeres

Back 8

myofilaments are organized into these arrangements

Front 9

myofibril

Back 9

a chain of sarcomeres

Front 10

myofiber

Back 10

a bundle of myofibrils

Front 11

myoblasts

Back 11

what muscle cells are composed of, embryonic muscle cells

Front 12

sarcolemma

Back 12

cell membrane that covers the muscle fibers

Front 13

endomysium

Back 13

myofiber is surrounded by a dleicate connective tissue layer called this

Front 14

fascicles

Back 14

bundles of fibers are organized into this, a bundle of this makes up a muscle

Front 15

perimysium

Back 15

a connective tissue layer that surrounds the fascicle

Front 16

epimysium

Back 16

connective tissue layer that sourounds the entire muscle

Front 17

actin

Back 17

a filamentous protein polymer made up of two strands of globular actin organized into a double helical configuration

Front 18

myosin

Back 18

attach to actin molecules, another kind of myofilaments

Front 19

sarcomere

Back 19

segment between two successive z bands

Front 20

A-band

Back 20

a dense middle band

Front 21

I-bands

Back 21

on either side of the A-bands, appear less dense,

Front 22

H-band

Back 22

consists of myosin

Front 23

sarcoplasmic reticulum

Back 23

syrrounds the myofibrils, mitochondria and are extensive endoplasmic reticulum

Front 24

T-tubules

Back 24

contacts the sarcoplasmic reticulum with teh sarcolmma(cell membrane), tubular process

Front 25

cisternae

Back 25

sac like compartments in the sarcoplasmic reticulum

Front 26

dark (red) fibers

Back 26

resistant to fatigue and contract relatively slowly, rely on oxidative phosphorylation, large number of mitochondria, large level of myoglobin

Front 27

myoglobin

Back 27

a protein similar to hemoglobin that binds oxygen

Front 28

light(white) fibers

Back 28

fatigue rapidly and contract rapidly, resort to anaerobic metabloic pathways, fewer mitochondria, less myoglobin, larger concentration of ATPase

Front 29

neurotransmitter

Back 29

chemical agent

Front 30

presynaptic membrane

Back 30

axonal membrane

Front 31

synaptic cleft

Back 31

the gap

Front 32

postsynaptic membrane

Back 32

sarcolemma

Front 33

neuromuscluar junction

Back 33

(synapse); presynaptic membrane, synaptic cleft, postsynaptic membrane

Front 34

all-or-none

Back 34

muscle fiber will either contract completely or not at all; not a muscle

Front 35

motor unit

Back 35

composed of a motor axon and all the myofibers

Front 36

fine movements

Back 36

few myofibers

Front 37

gross movements

Back 37

hundreds of myofibers

Front 38

unipennate

Back 38

muscles that have fibers running in an oblique direction on one side of a tendon

Front 39

bipennate

Back 39

muscle that has a single cenrtal tendon with bers coming obliquley off both sides of the tendon, feather shapped

Front 40

multipennate

Back 40

muscle that consists of several central tendons with oblique fibers attached to both sides of each tendon

Front 41

contraction

Back 41

a response to a stimulus

Front 42

isometric contraction

Back 42

length of the msucle does not change, tension increases

Front 43

isotonic contraction

Back 43

length of the muscle does change

Front 44

concentric contraction

Back 44

isotonic contractions in which the muscle fiber gets shorter

Front 45

eccentric

Back 45

isotonic contractions in which the muscle fiber lengthens

Front 46

agonist

Back 46

a muscle that is the prime cause of a particular action

Front 47

antagonist

Back 47

an agonist is opposed by this

Front 48

synergists

Back 48

restrict unwanted activity

Front 49

fixators

Back 49

stabilize the base of attachment for other muscles

Front 50

unijoint muscles

Back 50

cross only one joint

Front 51

multi joint muscles

Back 51

crossing more than one joint

Front 52

actively insufficient

Back 52

whent he multi joint muscle is acting as the agonist, unable to cause maximal shortening over all joints crossed

Front 53

passively insufficient

Back 53

if the multi joint muscle is acting as the antagonist, cannot lengthen completely over all joints crossed