PSIO 201 Practical 3

endomysium

layer of connective tissue surrounding individual muscle fibers

fascicle

a bundle of individual muscle fibers

perimysium

dense regular connective tissue surrounding fascicle

muscle

formed by groups of fascicles

epimysium

dense regular connective tissue surrounding muscles

tendons

- formed from endomysium, perimysium, and epimysium

- extend beyond each muscle fiber and attach muscle to bone

sarcolemma

- the plasma membrane

- conducts action potentials

- continuous with T-tubules

motor end plate

- portion of sarcolemma found underneath the synaptic end bulb

- houses achetylcholine receptors

triad

- made of 1 T-tubule and 2 terminal cisternae

sarcoplasmic reticulum

endoplasmic reticulum that is specialized to store calcium ions

the blue stuff

sarcomeres

-smallest structural and contractile unit of a muscle myofibril

-span from z disc to z disc

A-band

- dark band of striation

- extends the length of the thick filaments

A band = H zone + (2 x zone of overlap)

I-band

- light band of striation

- made of thin filaments

- isotropic band

M line

- line that is in the middle of a sarcomere

- middle of H zone and secures thick filaments

H zone

- contains M line

- starts at thick filaments

origin

fixed, immobile point of attachment for a muscle (usually more medial)

insertion

mobile portion of attachment (usually more lateral or distal)

muscle movement

agonist

prime mover

synergist

- helps the agonist

- performs the same set of actions as the synergist

antagonist

- muscle that works against the agonist

- as the agonist shortens (contracts), the antagonist lengthens (relaxes)

- ex: the triceps bracii is an antagonist to the biceps brachii

fixator

- stabilized the origin of the prime mover

- helps the agonist function the most efficiently

flexion, extension, and hyperextension

abduction

adduction

think of adding to the midline

circumduction

lateral rotation, medial rotation

elevation

depression

protraction

retraction

inversion

eversion

muscles of the face, head, and neck

frontalis

location: forehead

action: raises the eyebrows

occipitalis

location: back of the head

action: draws scalp posteriorly

orbicularis oris

location: circular muscle that encircles the mouth

action: puckers the mouth as in kissing

orbicularis oculi

location: circular muscle that encircles each eye

action: closes each eye as in blinking

zygomaticus major

location: originates on zygomatic bone and inserts on skin at the corners of the mouth

action: pulls the corners of the mouth superiorly as in smiling

zygomaticus minor

location: originates on the zygomatic bone and inserts on the upper lip

action: elevates upper lip, exposes upper teeth

above the major

platysma

location: originates on fascia of the chest and deltoid and inserts on the mandible and skin below the mouth (the neck)

action: depresses the lower lip and mandible; tenses neck skin

temporalis

location: originates on temporal bone and inserts on the mandible (side of head)

action: elevates and retracts the mandible

masseter

location: originates on maxillae and zygomatic bones and inserts on the mandible (cheek muscle)

action: elevates, protracts, and retracts the mandible

sternocleidomastoid

location: originates on the sternum and clavicle and inserts on the mastoid process of the temporal bone

action: if one side contracts, the head rotates to the opposite side. If both contract, flexion of the head occurs

muscles that move the vertebral column

rectus abdominis

location: originates on the pubis and inserts superiorly on the lower ribs and xiphoid process (ab muscles)

action: flexes the vertebral column and compresses the abdomen

external oblique

location: originates laterally on the lower ribs and inserts medially on the iliac crest and linea alba (side abs)

action: if one side contracts, the trunk rotates; if both sides contract together, the trunk contracts and the abdomen compresses

internal oblique

location: deep to external oblique

action: has the same action as external oblique

transversus abdominis

location: located deep to the internal oblique

action: compresses the abdomen

erector spinae:

- iliocostalis group

- longissimus group

- spinalis group

location: composite group of muscles that individually originate on vertebral processes or ribs and insert on superior processes of the vertebral column

action: when one side contracts, the muscles laterally flex and rotate the vertebral column; when both contract, the muscles extend vertebral column and maintain erect posture

muscles of respiration

diaphragm

location: originates on lower ribs and lumbar vertebrae, inserts in the middle on central tendon

action: inhaling, moves towards thoracic cavity and increases dimensions of thorax

external intercostals

location: between the ribs, insert on superior border of inferior rib

action: contraction pulls ribs upward and together expand the chest open

internal intercostals

location: between the ribs; insert on inferior border of superior rib

action: contraction pulls ribs down and decrease the dimensions of chest during expiration

muscles that move the pectoral girdle

pectoralis minor

location: anterior muscle of the chest; originates medially on the upper ribs and inserts laterally on the scapula

action: depresses and protracts the scapula

trapezius

location: posterior muscle of the upper back; originates medially on the occipital bone, lower cervical and thoracic vertebrae and inserts on the clavicle and scapula

action:

- superior portion elevates the scapula and clavicle and extends the head

- inferior portion depresses the scapula

levator scapulae

location: posterior muscle of the upper back that originates on the upper cervical vertebrae and inserts on the superior portion of the vertebral border of the scapula

action: elevates the scapula

rhomboid major

location: posterior muscle of upper back that originates on the upper thoracic vertebrae and inserts on the vertebral border of the scapula

action: elevates, adducts, and inferiorly rotates the scapula

rhomboid minor

location: posterior muscle of upper back that originates on lower cervical and upper thoracic vertebrae and inserts on the vertebral corner of the scapula

action: elevates, adducts, and inferiorly rotates the scapula

serratus anterior

location: originates on ribs 1-9 and inserts on vertebral border and inferior angle of scapula

action: abducts scapula and rotates it upward; "boxer's muscle" due to punching/pushing motion

muscles that move the arm

pectoralis major

location: originates on the clavicle, sternum and upper ribs and inserts laterally on the greater tubercle of the humerus

action: whole muscle adducts, and medially rotates the arm

latissimus dorsi

location: originates on the lower thoracic vertebrae and inserts on the anterior proximal humerus

action: adducts, extends, and medially rotates the arm

deltoid

location: large shoulder muscle that originates on the scapula posteriorly and clavicle anteriorly. inserts on deltoid tuberosity of humerus

action:

- medial fibers abduct arm

- anterior fibers flex and medially rotate arm

- posterior fibers extend and laterally rotate arm

supraspinatus

location: originates on scapula and inserts on humerus

action: abduct the arm

infraspinatus

location: originates on scapula and inserts on humerus

action: laterally rotates and adducts arm

teres major

location: originates on posterior surface of scapula and inserts on humerus

action: extends, adducts, and medially rotates arm

teres minor

location: originates on inferior border of scapula and inserts on humerus

action: extends, adducts, and laterally rotates the arm

subscapularis

location: originates on scapula and inserts on humerus

action: medially rotates the arm

muscles that move the forearm

biceps brachii

location: anterior of arm

action: flexes and supinates the forearm, flexes arm

brachialis

location: deep to biceps brachii

action: flexes the forearm

brachioradialis

location: originates on distal humerus and inserts on styloid process of radius

action: flexes the forearm

triceps brachii

location: muscle on posterior of arm with 3 points of origin

action: extend the forearm and extend the arm

pronator teres

location: originates on humerus and ulna, inserts on radius

action: pronates forearm and weakly flexes forearm

muscles that move the hand

flexor carpi radialis

action: flexes and abducts hand

flexor carpi ulnaris

action: flexes and adducts hand

palmaris longus

location: goes to the center of the fingers (3 middle ones)

action: flexes the hand

flexor digitorum superficialis

location: superficial anterior forearm. inserts on the digits of each finger

action: flexes the digits and the hand

flexor digitorum profundus

location: deep anterior forearm

action: flexes the digits and hand

extensor digitorum

location: superficial posterior forearm.

action: extends the digits and hand

extensor carpi ulnaris

location: superficial posterior forearm

action: extends and adducts the hand

extensor carpi radialus longus

location: superficial posterior arm

action: extends and abducts the hand

extensor carpi radialus brevis

location: deep posterior forearm

action: extends and abducts hand

extensor digiti minimi

location: superficial posterior forearm

action: extends the digits and the hand

abductor pollicis longus

location: deep posterior forearm, diagonal one

action: abducts and extends thumb/pollicis and abducts hand

extensor pollicis brevis

location: deep posterior forearm

action: extends thumb/pollicis and abducts the hand

muscles that move the thigh

iliopsoas iliacus & soas major

location: the anterior hip

action: both muscles act to flex the thigh

piriformus

location: deep muscle of the gluteal region

action: laterally rotates and abducts the thigh

tensor fascia latae

location: lateral hip and thigh

action: flexes and abducts the thigh

gluteus maximus

location: large superficial muscle of posterior hip

action: extends and laterally rotates the thigh

gluteus minimus

location: deep to gluteus medium

action: abducts and medially rotates the thigh

gluteus medius

location: deep to gluteus maximus

action: abducts and medially rotates the thigh

gracilis

location: muscle of medial thigh

action: adducts the thigh and flexes the leg

adductor magnus

location: deep adductor muscle

action: adducts and medially rotates the thigh

adductor longus

location: originates on pubis and inserts on femur

action: adducts, flexes, and medially rotates the thigh

adductor brevis

location: originates on pubis and inserts on femur

action: adducts, medially rotates and flexes the thigh