Anatomy Topic 4

Front 1

muscle fibers

Back 1

elongated cells that possess organelles and properties distinct from those of other cells
- long, slender cells
- capable of powerful contractions that shorten the cell along its lonitudinal axis

Front 2

cardiac muscle tissue

Back 2

found only in the heart
-involuntary

Front 3

smooth muscle tissue

Back 3

found in the walls of blood vessels, around hollow organs such as the urinary bladder, and in layers around the respiratory, ciculatory, digestive and reproductive tracts
- involuntary

Front 4

skeletal muscle tissue

Back 4

contains very large muscle cells
- voluntary

Front 5

4 properties of muscle tissue

Back 5

1) excitability - ability to respond to stimulation
2) contractility - ability to shorten actively
3) extensibility - ability to continue to contract over a range of resting lenths
4) elasticity - ability to rebound to original lenght after contraction

Front 6

skeletal muscle functions

Back 6

1) produce skeletal movement
2) maintain posture and body position
3) support soft tissue
4) regulate entering and exiting material
5) maintain body temperature

Front 7

endomysium

Back 7

delicate network of reticular fibers that surround each skeletal muscle fiber and binds it to its neighbor

Front 8

perimysium

Back 8

fibrous sheaths of connective tissue that divide muscle into a series of internal compartments called fascicles
- fibers = collagen & elastic fibers
- contains blood vessels and nerves

Front 9

epimysium

Back 9

dense irregular connective tissue layer that surround entire muscle

Front 10

tendons

Back 10

fibers of endoymysium, perimysium, and epimysium often converge to form a fibrous tendon that attaches the muscle to bone, skin, or another muscle

Front 11

aponeurosis

Back 11

tendon that forms a thick, flattened sheet

Front 12

T-tubule

Back 12

transverse, tubular extensions of the skeletal muscle cell membrane that extend deep into the cytoplasm to contact the sarcoplasmic reticulum
- helps stimulate and coordinate muscle contraction

Front 13

sarcolemma

Back 13

muscle cell membrane

Front 14

sarcoplasm

Back 14

muscle cell cytoplasm

Front 15

myofibril

Back 15

threadlike cylinders in the sarcoplasm of each muscle fiber that shorten during contraction

Front 16

myofilaments

Back 16

protein filaments within each myofibril
- actin and myosin

Front 17

myosin

Back 17

thick filaments

Front 18

actin

Back 18

thin filaments

Front 19

sarcomere

Back 19

reapeating units of myofilaments

Front 20

sarcoplasmic reticulum

Back 20

membrane complex that surrounds each myofibril
- similar to smooth ER of other cells

Front 21

M line

Back 21

thick dark protein band in center of H band that links thick filaments

Front 22

Z line

Back 22

thin but dark protein band to which thin filments ar attached
- sarcomere runs from Z line to Z line

Front 23

zone of overlap

Back 23

area of sarcomere where thin filaments pass between thick filaments

Front 24

A band

Back 24

are of sarcomere containing M line, H band, and zone of overlap

Front 25

H band

Back 25

area of sarcomere with thick filaments only

Front 26

I band

Back 26

area of sarcomere with thin filaments only

Front 27

F-actin strand

Back 27

twisted strand composed of 300-400 G-actin molecules

Front 28

G-actin

Back 28

each molecule of G-actin contains an active site than can bind to a thick filament

Front 29

nebulin

Back 29

slender strand of protein that hold F-actin strand together

Front 30

tropomyosin

Back 30

associated proteins that form a long chain that covers the active sites fo the thin filaments, preventing actin-myosin interaction

Front 31

troponin

Back 31

associated proteins that hold the tropomyosin strand in place
- changes position to move the tropomyosin to expose active sites for contraction

Front 32

myosin

Back 32

consist of a double myosin strand with an attached, elongated tail and a free globular head
- adjacent thick filaments are interconnected midway along their lenthy by proteins of M line
- oriented away from M line, heads projecting out
- myosin heads cross-bridges because connect thick and thin filaments during contraction

Front 33

titin

Back 33

core protein in thick filament that extends the length and continues ot an attachment at the Z line
- portion of titin exposed in I band is elastic and will recoil after stretching

Front 34

acetylcholine (ACh)

Back 34

chemical neurotransmitter released at the neuromuscular junction

Front 35

acetylcholinesterase (AChE)

Back 35

enzyme found at the synaptic cleft, bound to the post-synaptic membrane that breaks down ACh molecules

Front 36

rigor mortis

Back 36

muscles lock in contracted postion when death occurs

Front 37

motor unit

Back 37

all of the muscle cells controlled by a single motor neuron

Front 38

muscle twitch

Back 38

single momentary contraction
- response to a single stimulus

Front 39

all or none principle

Back 39

each muscle fiber contracts completely or it doesn't contract at all

Front 40

muscle tone

Back 40

resting tension in a skeletal muscle

Front 41

muscle spindles

Back 41

specialized muscle cells that are monitored by sensory nerves that control the muscle tone in the surrounding tissue

Front 42

muscle hypertrophy

Back 42

net enlargement of skeletal muscle

Front 43

muscle atrophy

Back 43

reduction in muscle size

Front 44

fast fibers

Back 44

(white fibers), large diameter, paler color, easily fatigued, powerful contractions
- anaerobic

Front 45

slow fibers

Back 45

(red fibers), smaller diameter, darker color from myoglobin, fatigue resistant, slower but extended contractions
- aerobic metabolism

Front 46

intermediate fibers

Back 46

properties intermediate between fast and slow fibers

Front 47

parallel muscle

Back 47

biceps brachii muscle

Front 48

convergent muscle

Back 48

pectoralis muscles

Front 49

unipennate muscle

Back 49

extensor digitorum muscle
- one side of tendon

Front 50

bipennate muscle

Back 50

rectus femoris muscle
- both sides of tendon

Front 51

multipennate muscle

Back 51

deltoid muscle
- multiple branches, tendons throughout

Front 52

circular muscle

Back 52

orbicularis oris muscle
- circle around opening

Front 53

origin

Back 53

where muscle begins
- structure on a bone of the skeleton that usually remains stationary

Front 54

insertion

Back 54

where muscle ends
- structure on a bone of the skeleton that usually moves

Front 55

innervation

Back 55

nerve supply to a particular structure or organ
- controls action

Front 56

action

Back 56

movement

Front 57

gliding

Back 57

two opposing surgaces slide past one another

Front 58

abduction

Back 58

movement away from the longitudinal axis of the body in the frontal plane

Front 59

adduction

Back 59

movement towards the longitudinal axis of the bpdy

Front 60

flexion

Back 60

movement in the anterior-posterior plane that decreases the angle between articulating elements

Front 61

extension

Back 61

movement in the anterior-posterior plane that increases the angle between articulating elements

Front 62

hyperextension

Back 62

any movement where a limb is extended beyond its normal limits, resulting in joint damage

Front 63

circumduction

Back 63

special type of angular motion that creates a complete circle

Front 64

left and right rotaiton

Back 64

in reference to head as in shaking no
- reference to subject, not observer

Front 65

internal or medial rotation

Back 65

anterior aspect of the limb rotates inward, toward the ventral surface of the body

Front 66

external or lateral rotation

Back 66

anterior aspect of the limb rotates outward, away from the ventral surface of the body

Front 67

pronation

Back 67

movement of wrist and hand to palm-facing down position

Front 68

supination

Back 68

movement of wrist and hand to palm-facing up position

Front 69

eversion

Back 69

twisting motion of the foot that turns the sole outward

Front 70

inversion

Back 70

twisitng motion of the foot that turns the sole inward

Front 71

dorsiflexion

Back 71

(ankle flexion) elevates the distal part of foot and toes, as when digging in heels (flex)

Front 72

plantar flexion

Back 72

(ankle extension) elevates the heel and proximal portion of foot, as when standing on tip toes (point)

Front 73

lateral flexion

Back 73

vertebral column bends to the side

Front 74

protraction

Back 74

moving a part of the body anteriorly in the horizontal plane

Front 75

retraction

Back 75

moving a part of the body posteriorly in the horizontal plane

Front 76

aging and the skeletal muscle

Back 76

1) skeletal muscle fibers become smaller in diameter
2) skeletal muscles become smaller in diameter and less elastic
3) tolerance for exercise decreases
4) ability to recover from muscular injuries decreases

Front 77

axial musculature

Back 77

- originates and inserts on the axial skeleton
- positions the head and vertebral colum
- moves the rib cage which assists in breathing
- 60% of the skeletal muscles in the body

Front 78

appendicular musculature

Back 78

- responsible for stabilizing the pectoral and pelvic girdles
- responsible for moving the upper and lower limbs
- 40% of muscles in body

Front 79

intramuscular injections

Back 79

into tissue rather than directly into circulation
- drug enters circulation gradually
- into mass of large skeletal muscle
- faster and less irritation

Front 80

ideal injection sites

Back 80

bulky muscles that contain few large vessels or nerves
- gluteus medius
- deltoid
- vastus lateralis