Anatomy Final Unit 2 Part Two

Front 1

____ muscle tissue can contract rapidly and with great force, but tires quickly

Back 1

skeletal

Front 2

organization of skeletal muscle fibers

Back 2

--each fiber is enclosed in a delicate connective tissue sheath called endomysium

--several sheathed muscle fibers are then wrapped by a coarser fibrous membrane called a perimysium to form a bundle of fibers called a fascicle

--fascicles are then bound together by a connective tissue overcoat called epimysium

Front 3

tendons

Back 3

mostly tough collagen fibers

anchor muscles

provide durability

conserve space

Front 4

smooth muscle structure

Back 4

spindle-shaped

single nucleus

surrounded by scant endomysium

arranged into layers (usually 2 layers total), one that runs circularly and one that runs longitudinally (these two layers relax and contract alternately)

Front 5

______ muscle contraction is slow and sustained

Back 5

smooth

Front 6

functions of skeletal muscle

Back 6

1. produces movement

2. maintains posture

3. stabilizes joints

4. generates heat

Front 7

skeletal muscle accounts for _____% of body mass

Back 7

40%

Front 8

Z disk

Back 8

interruption in light (I) band, darker area

Front 9

H zone

Back 9

lighter central zone of the dark (A) band that has an M line at the center that contains tiny protein rods that hold adjacent thick filaments together

bare zone

Front 10

myofibrils

Back 10

organelles of skeletal muscle cells

composed of chains of tiny contractile units called sarcomeres (made up of even smaller fibers called myofibrils)

Front 11

thick filaments

Back 11

myosin

contain ATPase enzymes

extend entire length of dark A band

midparts are smooth but the ends are studded with small projections (myosin heads aka crossbridges)

Front 12

function of cross bridges

Back 12

to link thick and thin filaments together during muscle contraction

Front 13

thin filaments

Back 13

actin

regulatory proteins that dictate when myosin heads can bind to thin filaments

anchored to the Z disk

do not extend into the middle of a relaxed sarcomere

Front 14

skeletal muscle contraction in the sarcomere

Back 14

actin-containing filaments slide toward each other into the center of sarcomere, causing light zones to disappear because actin and myosin are completely overlapped

Front 15

sarcoplasmic reticulum

Back 15

stores calcium and releases it to facilitate muscle fiber contraction

Front 16

special properties of muscle cells

Back 16

1. excitability

2. contractility

3. extensibility

4. elasticity

Front 17

motor unit

Back 17

motor neuron and all of the skeletal muscle cells that it innervates

Front 18

events at neuromuscular junction

Back 18

1. action potential reaches axon terminal of motor neuron

2. calcium channels open and Ca2+ enters the axon terminal

3. Ca2+ entry causes some synaptic vesicles to release the neurotransmitter ACh into the synaptic cleft

4. ACh diffuses across synaptic cleft and binds to receptors in sarcolemma

5. ACh binds to receptors, causing channels to open, and Na+ passes into muscle fiber while K+ simultaneously leaves the muscle fiber. More Na+ enter than K+ leave, resulting in depolarization of the cell and the production of an action potential.

Front 19

events that return muscle cell to its resting state

Back 19

1. diffusion of K+ out of the cell

2. operation of sodium-potassium pump moves ions via active transport back to their starting positions

Front 20

____ ions trigger the binding of actin to myosin

Back 20

Ca2+

Front 21

how are graded responses produced?

Back 21

1. changing frequency of muscular stimulation

2. changing the number of muscle cells being stimulated at one time

Front 22

fused tetanus

Back 22

when the muscle is stimulated so rapidly that no evidence of relaxation can be seen and the contractions are completely smooth and sustained

Front 23

direct phosphorylation of ADP by creatine phosphate

Back 23

very quick (takes a fraction of a second to produce more ATP)

although extensive, each cell's store of creatine phosphate is exhausted in 15 seconds

Front 24

aerobic respiration

Back 24

provides 95% of ATP for muscle activity

slow

provides 32 ATP per glucose molecule

requires constant supply of nutrients and oxygen

Front 25

anaerobic glycolysis and lactic acid formation

Back 25

used during intense muscle activity

glycolysis yields 2 ATP per glucose molecule

pyruvic acid is converted to lactic acid

2.5x faster than aerobic respiration

can provide ATP to fuel 30-40 seconds of strenuous muscle activity

Front 26

isotonic contraction

Back 26

myofibrils slide past one another

muscle shortens

movement occurs

Front 27

isometric contraction

Back 27

contractions in which muscles do not shorten

Front 28

five golden rules of skeletal muscle activity

Back 28

1. almost all skeletal muscles cross at leas one joint

2. typically bulk of muscle lies proximal to joint crossed

3. all skeletal muscles have at least two attachments (origin and insertion)

4. skeletal muscles can only pull, they never push

5. during contraction, a muscle insertion moves toward the origin

Front 29

origin

Back 29

muscle attachment at immovable or less moveable bone

Front 30

insertion

Back 30

muscle attachment to moveable bone

Front 31

a muscle that crosses on the anterior side of a joint produces _______

Back 31

flexion

Front 32

a muscle that crosses on the posterior side of a joint produces _______

Back 32

extension

Front 33

a muscle that crosses on the lateral side of a joint causes ____

Back 33

abduction

Front 34

a muscle that crosses on the medial side of a joint produces _____

Back 34

adduction

Front 35

circular arrangement of fascicles

Back 35

when fascicles are arranged in concentric rings typically found around external body openings

"sphincters"

Front 36

convergent arrangement of fascicles

Back 36

fascicles converge toward a single insertion tendon

muscles are usually triangular or fan-shaped

Front 37

parallel arrangement of fascicles

Back 37

length of fascicles run parallel to the long axis of the muscle

straplike muscles

Front 38

fusiform arrangement of fascicles

Back 38

variation of parallel

spindle shaped muscle with an expanded belly

Front 39

pennate arrangement of fascicles

Back 39

short fascicles attach obliquely to a central tendon

Front 40

pectoralis major

Back 40

large, fan-shaped muscle covering upper part of chest that forms anterior wall of axilla

origin: sternum, clavicle, and 1st-6th ribs

insertion: proximal humerus

function: adducts and flexes humerus

Front 41

intercostal muscles

Back 41

deep muscles located between ribs

external intercostals: used during inhalation

internal intercostals: used in forced exhalation

Front 42

rectus abdominus

Back 42

paired

most superficial muscles of abdomen

enclosed in apneurosis

origin: pubis

insertion: sternum and 5-7th ribs

function: flexes vertebral column, also compresses abdominal contents during defecation and childbirth

Front 43

external obliques

Back 43

make up lateral walls of abdomen

paired superficial muscles

origin: lower 8 ribs

insertion: iliac crest

function: flexes and rotates vertebral column

Front 44

internal obliques

Back 44

deep to external obliques

origin: iliac crest

insertion: last three ribs

function: flex vertebral column, rotate trunk and bend trunk laterally

Front 45

transversus abdominus

Back 45

deepest muscle of abdominal wall

fibers run horizontally across the abdomen

origin: lower ribs and iliac crest

insertion: pubis

function: compresses abdominal contents

Front 46

deltoid

Back 46

triangle-shaped

origin: scapular spine and clavicle

insertion: proximal humerus (deltoid tuberosity)

function: abducts humerus

Front 47

quadratus lumborum

Back 47

form part of posterior abdominal wall

origin: iliac crest, lumbar fascia

insertion: transverse processes of upper lumbar vertebrae

function: flex spine laterally (when acting separately) or extends spine (when acting together)

Front 48

erector spinae

Back 48

paired deep muscles of back that span entire length of vertebral column

origin: iliac crests, ribs 3-12, and vertebrae

insertion: ribs, thoracic and cervical vertebrae

function: extends and laterally flexes spine

longissimus, iliocostalis, spinalis

Front 49

trapezius

Back 49

most superficial muscles of posterior neck and upper trunk

diamond/kite-shaped

antagonists of sternocleidomastoids

origin: occipital bone and all cervical and thoracic vertebrae

insertion: scapular spine and clavicle

function: extend head; depress, elevate, adduct, and stabilize scapula

Front 50

latissimus dorsi

Back 50

paired large flat muscles that cover lower back

origin: lower spine and iliac crest

insertion: proximal humerus

function: extends and adducts humerus

Front 51

gluteus maximus

Back 51

superficial muscle of hip

makes up most of flesh in buttocks

origin: sacrum and ilium

insertion: proximal femur (gluteal tuberosity)

function: extends hip when forceful extension is required; is not essential or particularly important in producing the movements needed for walking

Front 52

gluteus medius

Back 52

beneath gluteus maximus for most of its length

origin: ilium

insertion: proximal femur

function: abducts thigh, steadies pelvis during walking

Front 53

iliopsoas

Back 53

fused muscle composed of iliacus and psoas major

prime mover of hip flexion

origin: ilium and lumbar

insertion: femur (lesser trochanter)

function: flexes hip

Front 54

fibularis muscles (longus, brevis, tertius)

Back 54

lateral part of leg

origin: fibular

insertion: metatarsals of foot

function: plantarflexion and eversion of foot

Front 55

soleus

Back 55

deep to gastrocnemius

origin: proximal tibia and fibula (does not affect knee movement)

insertion: calcaneus

function: plantarflexion of foot

Front 56

gastrocnemius

Back 56

forms curved calf of posterior leg

has 2 heads

origin: each head attaches on either side of distal femur

insertion: calcaneus (heel via calcaneal tendon)

function: prime mover of plantarflexion of foot; flexes knee

Front 57

extensor digitorum longus

Back 57

lateral to tibialis anterior

origin: proximal tibia (lateral tibial condyle) and proximal 3/4 of fibula

insertion: phalanges of distal toes 2-5

function: prime mover of toe extension

Front 58

tibialis anterior

Back 58

superficial muscle on anterior leg

origin: upper proximal tibia

insertion: first cuneiform (tarsal) and first metatarsal of foot

function: dorsiflexion and inversion of foot

Front 59

what muscles make up the quadriceps

Back 59

vastus medialis

vastus intermedius

vastus lateralus

rectus femoris

Front 60

quadriceps group

Back 60

origin: femur (vasti) and pelvis (rectus femoris)

insertion: tibial tuberosity via patellar ligament

function: all extend knee; rectus femoris also flexes hip because it crosses two joints

Front 61

sartorius

Back 61

most superficial muscle of thigh

origin: ilium

insertion: medial proximal tibia

function: flexes thigh on hip (weakly)

Front 62

what muscles make up the hamstring

Back 62

semitendinosus

semimembranosus

biceps femoris

Front 63

hamstring group

Back 63

origin: ischial tuberosity

insertion: both sides of the proximal tibia and head of fibula in the case of biceps femoris

function: extend hip and thigh, flex knee

Front 64

adductor muscles

Back 64

medial side of each thigh

origin: pelvis

insertion: proximal aspect of femur

function: adduct and medially rotate thigh

Front 65

frontalis

Back 65

origin: cranial aponeurosis

insertion: skin of eyebrows

function: raises eyebrows, wrinkles forehead

Front 66

occipitalis

Back 66

at posterior end of cranial aponeurosis

covers posterior aspect of skull

pulls scalp posteriorly

Front 67

orbicularis oculi

Back 67

fibers run in circles around the eyes

origin: frontal bone and maxilla

insertion: tissue around eyes

function: blinking, closing eye, winking, squinting

Front 68

orbicularis oris

Back 68

kissing muscle

origin: mandible and maxilla

insertion: skin and muscle around mouth

function: closes and protrudes lips

Front 69

buccinator

Back 69

runs horizontally across cheek

origin: maxilla and mandible near molars

insertion: orbicularis oris

function: compresses cheek (as in sucking), holds food between teeth when chewing

Front 70

zygomaticus

Back 70

smiling muscle

origin: zygomatic bone

insertion: skin and muscle at corners of lips

function: raises corners of mouth

Front 71

temporalis

Back 71

fan-shaped, overlying temporal bone

origin: temporal bone

insertion: mandible

function: closes jaw, works as synergist with masster

Front 72

masseter

Back 72

covers angle of lower jaw

origin: zygomatic process of temporal bone

insertion: angle of mandible

function: closes jaw by elevating mandible

Front 73

platysma

Back 73

single sheet-like muscle that covers anterolateral neck

frowning muscle

origin: connective tissue covering superior chest muscles

insertion: tissue around mouth

function: tenses skin around neck

Front 74

sternocleidomastoid

Back 74

2 headed muscle

origin: one head at sternum and one head at clavicle (heads fuse before insertion)

insertion: mastoid process of temporal bone

function: flexes neck (when working together) and rotates head (when working alone)

Front 75

biceps brachii

Back 75

2 heads

powerful prime mover of elbow flexion

origin: scapula of the shoulder girdle

insertion: radial tuberosity of proximal radius

function: flexes elbow and suppinates forearm

Front 76

brachialis

Back 76

lifts ulna as biceps lifts the radius

deep to biceps

origin: distal humerus

insertion: proximal ulna

function: flexes elbow

Front 77

triceps brachii

Back 77

antagonist to biceps brachii

only muscle fleshing out posterior humerus

origin: shoulder girdle and proximal humerus

insertion: olecranon process of ulna in distal forearm

function: extends elbow

Front 78

extensor digitorum

Back 78

origin: distal humerus

insertion: distal phalanges of 2nd to 5th fingers

function: extends fingers

Front 79

extensor carpi radialis

Back 79

origin: humerus

insertion: base of 2nd and 3rd metacarpals

function: extends wrist and abducts hand

Front 80

flexor carpi ulnaris

Back 80

origin: distal humerus and posterior ulna

insertion: carpals of wrist and fifth metacarpal

function: flexes wrist and adducts hand

Front 81

flexor carpi radialis:

Back 81

origin: distal humerus

insertion: 2nd and 3rd metacarpals

primary actions: flexes wrist and abducts hand

Front 82

flexor digitorum superficialis

Back 82

origin: distal humerus, ulna, and radius

insertion: middle phalanges of 2nd to 5th fingers

function: flexes wrist and fingers