lab practical 2

epimysium

surrounds entire skeletal muscle

- dense irregular connective tissue

perimysium (perimeter)

- areolar connective tissue surrounding a fascicle

- separates muscle cells/fibers into bundles

fascicle

bundle of muscle fibers

endomysium (inside)

- areolar connective tissue surrounding each separate muscle cell/fiber

- carry blood vessels/sources

muscle fiber/cell

each cell stretches the length of muscle, surrounded by a plasma membrane and a layer of connective tissue called endomysium

- bundles of myofibrils

- composed of several myofibrils wrapped together by a sarcolema and sarcoplasm

myofibril

long, filamentous organelles found within muscle fibers/cells that has a banded appearance

- propagate muscle contraction

myofilaments

filaments of myofibrils that are constructed from proteins and are responsible for muscle contraction

- actin (thin)

- myosin (thick)

agonist or prime mover

primary responsible for producing a particular movement

- the muscle that does most of the work during a movement

antagonist

a muscle that has the opposite function to another muscle

- works in the opposite direction during a movement and stabilizes the other muscle

- keeps body in stable position

synergist

muscle that aids a prime mover in a movement and helps prevent rotation

origin of a muscle

muscle end attached to the bone that stabilizes the movement and does not move when the muscle contracts

insertion of a muscle

muscle end attached to the bone that drives the movement and moves when the muscle contracts

flexion

bending a joint by decreasing the angle

extension

straightening of a joint by increasing the angle

hyperextension

extension beyond anatomical position

dorsiflexion

bending of the foot or the toes upward

plantar flexion

bends the foot downward toward the ground at the ankle

abduction

movement away from the midline of the body

adduction

movement toward the midline of the body

rotation

movement where bone rotates on its long axis/fixed point

circumduction

the circular movement at the far end of a limb

supination

movement that turns the palm up

pronation

turning the palm downward

elevation

raising a body part

depression

lowering a body part

protraction

moving a body part forward and parallel to the ground

retraction

moving a body part backward and parallel to the ground

orbicularis oculi

closes eyelids

- used in blinking, winking, and squinting

frontalis (frontal belly)

raise eyebrow; moves scalp and wrinkles forehead

zygomaticus major

raises lateral corners of mouth upward (smiling muscle)

zygomaticus minor

retracts and elevates upper lip

temporalis

elevates and retracts mandible (closes jaw)

orbicularis oris

closes and protrudes lips; kissing muscle

risorius

draws corner of mouth laterally (grimace)

risorius laterally

levator labii superioris

elevates upper lip

buccinator

compresses cheek (sucks them in); holds food between teeth during chewing

masseter

elevates mandible (closes jaw)

external and internal intercostals

expands and lowers the ribs during breathing

external and internal obliques

flex and rotate vertebral column, compress abdomen

transversus abdominus

compresses abdominal cavity

rectus abdominus

flexes vertebral column and compresses abdomen; commonly known as the "six pack"

- responsible for movement in the abdominal cavity

serratus anterior

protracts scapula; assists in upward rotation of scapula

- spread almost all the way down the ribs

diaphragm

large, flat muscle at the bottom of the chest cavity that regulates breathing

pectoralis major

adduction and internal rotation of the humerus; inwards movement of the arms

- origin: clavicle and sternum

- insertion: humerus

- antagonist: latissimus dorsi and deltoid

pectoralis minor

protracts and depresses scapula

- origin: ribs 3-5

- insertion: scapula

- antagonist: trapezius

platysma

- draws down the lower lip and angles of the mouth

- tenses skin of the neck

- helps depress mandible

sternocleidomastoid

flexes and laterally rotates the head

- origin: sternum and clavicle

- insertion: temporal bone

levator scapulae

elevates scapula

- origin: cervical vertebrae

- insertion: scapula

scalenes

elevates first two ribs; postural muscles that maintain position of the neck and cervical track

scalenes peeled back

- anterior, posterior, and medial

erector spinae group

extends vertebral column

- spinalis, longissimus, iliocostalis

spinalus

extends vertebral column

- origin: upper vertebrae

- insertion: lower vertebrae

longissimus

extends vertebral column

- origin: upper vertebrae

- insertion: lower vertebrae

iliocostalus

extends vertebral column

- origin: iliac crest

- insertion: vertebrae

quadratus lumborum

flexes the spine laterally

rhomboid major

retracts the scapula

- origin: vertebrae

- insertion: scapula

- antagonist: serratus anterior

rhomboid minor

retracts the scapula

- origin: vertebrae

- insertion: scapula

- antagonist: serratus anterior

splenius capitis

extends and rotates head

- origin: vertebrae

- insertion: temporal bone

trapezius

elevates, depresses, retracts, and rotates the scapula; rotates the arm

- origin: vertebrae

- insertion: scapula

- antagonist: lower trapezius

latissimus dorsi

extends, adducts, and medially rotates the arm; draws the shoulder downward and backward

- origin: vertebrae

- insertion: humerus

- antagonist: deltoids

deltoid

abducts arm at shoulder

- origin: clavicle and scapula

- insertion: humerus

- antagonist: latissimus dorsi and pectoralis major

supraspinatus

abduction of shoulder

- origin: scapula

- insertion: humerus

infraspinatus

lateral rotation at shoulder

- origin: scapula

- insertion: humerus

subscapularis

medially rotates arm, stabilizes shoulder joint

teres major

medial rotation of shoulder joint

- origin: scapula

- insertion: humerus

teres minor

lateral rotation of shoulder joint

- origin: scapula

- insertion: humerus

biceps brachii short head

flexes and supinates forearm

- origin: scapula

- insertion: radius

- antagonist: triceps brachii

biceps brachii long head

flexes and supinates forearm

- origin: scapula

- insertion: radius

- antagonist: triceps brachii

brachialis

flexes forearm at elbow

- origin: humerus

- insertion: ulna

- antagonist: triceps brachii

brachioradialis

flexes forearm at elbow

- origin: humerus

- insertion: radius

triceps brachii

extends forearm at elbow joint

- origin: scapula and humerus

- insertion: ulna

- antagonist: biceps brachii and brachialis

anterior forearm

muscles that flex the hand at the wrist

posterior forearm

muscles that extend the hand at the wrist

supinator (posterior)

supination of forearm

- origin: humerus and proximal ulna

- insertion: proximal end of radius

pronator teres

pronation of forearm

- origin: humerus

- insertion: radius

palmaris longus

flexes the wrist

- origin: humerus

- insertion: metacarpals

flexor carpi radialis

flexes the wrist

- origin: humerus

- insertion: metacarpals

flexor carpi ulnaris

flexes the wrist

- origin: humerus

- insertion: metacarpals

another view of flexor carpi radialis and ulnaris

extensor carpi radialis longus (posterior)

extends the wrist

- origin: humerus

- insertion: metacarpals

extensor carpi ulnaris (posterior)

extends the wrist

- origin: humerus

- insertion: metacarpals

flexor digitorum (anterior)

flexes wrist and digits

- origin: ulna

- insertion: metacarpals

extensor digitorum (posterior)

extends wrists and digits

- origin: humerus

- insertion: metacarpals

anconeus (posterior)

extension of elbow

- origin: humerus

- insertion: ulna

gluteus maximus

extends thigh at hip

- origin: ilium, sacrum and coccyx

- insertion: femur

gluteus medius

abducts and medially rotates thigh; steadies pelvis

- origin: ilium

- insertion: femur

another view of gluteus medius

tensor fasciae latae

abducts and medially rotates thigh

- origin: ilium

- insertion: iliotibial tract

- antagonist: gluteus maximus (all gluteal muscles/hip abducting muscles)

adductor muscles

adduct and flex thigh at the hip

adductor brevis

adducts and flexes thigh at hip

- origin: pubic bone

- insertion: femur

- antagonist: gluteus maximus (all gluteal muscles/hip abducting muscles)

another view of adductor brevis

adductor magnus

adducts and flexes thigh at hip

- origin: pubic bone

- insertion: femur

- antagonist: gluteus maximus (all gluteal muscles/hip abducting muscles)

another view of adductor magnus

adductor longus

adducts and flexes thigh at hip

- origin: pubic bone

- insertion: femur

- antagonist: gluteus maximus (all gluteal muscles/hip abducting muscles)

another view of adductor longus

gracilis

adducts and flexes thigh at hip

- origin: pubic

- insertion: femur

- antagonist: gluteus maximus and adductor magnus

pectineus

adducts and flexes thigh at hip

- origin: pubic bone

- insertions: femur

- antagonist: gluteus maximus

another view of pectineus

iliacus

flexes thigh at hip

- origin: ilium

- insertion femur

- antagonist: gluteus maximus and hamstrings