The Muscular System

major functions of muscular system

The muscles

3 types of muscle tissues

body movement terminology

skeletal muscle

cardiac muscle

smooth muscle

found in walls of hollow, visceral organs

ex: stomach, urinary bladder, respiratory passages

meant to force fluids and other substances through internal body channels

forms valves to regulate passage of substances in internal bod. openings

consists of elongated cells but no striations

contractions are not voluntary

they're slow and sustained

packaged into skeletal muscles

are longest muscle cells, and have striations

activated by reflexes; but is still voluntary

responsible for overall mobility, can tire out easily

only at heart

striated cells

not voluntary

produce movement

maintain posture and body position

stabilize joints

generate heat

skeletal muscles=locomotion and manipulation

blood courses cause of beating cardiac muscle in our heart & smooth muscle in walls of blood vessels =maintain blood pressure

smooth muscle in organs of digestive, urinary, and reproductive tracts propel substances through organs

skeletal muscle maintain body posture

pull bones to cause movement; strengthen & stabilize joints in skeleton

muscles make heat as they contract

plays role in maintaining normal body temperature

muscles on arms

muscles on legs/thighs

muscles on trunk

muscles on head/neck

masseter

prime mover of jaw; around mandible; jawline area

temporalis

fan shaped muscle; head

buccinator

the mouth area; before the masseter

sternocleidomastoid

deep in platysma; flexes and laterally rotates head

platysma

around neck, plays a role with facial expressions; can make lower lip go down

trapezius

pectoralis major

major back muscle; responsible for rotating and stabilizing the scapula

deltoid

thick multipennate muscle; prime mover of arm abduction when all its fibers contact simultaneously

cover superior portion of chest; adducts and medially rotates arm

rectus abdominis

the abs area; most superficial muscle pair; extend pubis to rib cage; flex and rotate lumbar region of vertebral column

external oblique

largest and superficial of three lateral muscles; flex vertebral column and compress abdominal wall

latissimus dorsi

broad, flat, triangular muscle on lower back; lumbar region; prime mover of arm extension; powerful arm adductor; medially rotates arm

infraspinatus

partially covered by deltoid & trapezius; rotates arm medially

teres major

thick, rounded muscle; extends medially rotates and adducts arm

tricep brachii

large fleshy muscle; powerful forearm extensor

bicep brachii

2 headed fusiform muscle; flexes and supinates forearm

brachialis

strong muscle that is immediately deep to biceps brachii; a major forearm flexor

brachioradialis

superficial muscle of lateral forearm; synergist in flexing forearm

flexor carpi radialis

runs diagonally across forearm; strong flexor of hand

flexor carpi ulnaris

most medial muscle of this group; strong flexor and adductor of hand

extensor carpi radialis longus

parallels brachioradialis on lateral forearm; extends hand

extensor digitorum

lies medial to extensor carpi radialis brevis; prime mover of finger extension

rectus femoris

gracilis

vastus lateralis

vastus medialis

fibularis longus

extensor digitorum longus

tibialis anterior

gastrocnemius

soleus

bicep femoris

semimembranosus

iliopsoas

adductor longus

sartorius

straplike superficial muscle; flexes, adducts, laterally rotates thigh

overlies middle aspect of adductor magnus; adducts, flexes, and medially rotates thigh

hip

superficial muscle of anterior thigh; extends leg and flexes thigh at the hip

largest head of the group; extends leg and stabilizes knee

forms inferomedial aspect of thigh; extends knee

superficial muscle of anterior leg; prime mover of dorsiflexion

superficial lateral muscle overlies fibula; plantar flexes and everts foot

broad, flat muscle, deep to gastrocnemius; plantar flexes foot

superficial muscle of pair; plantar flexes foot

unipennate muscle on anterolateral surface of leg; prime mover of toe extension

most lateral muscle of the group; extends thigh and flexes leg

deep to semitendinosus; extends thigh and flexes leg

found at groin; helps with hip adduction and knee flexion

gliding

move hand from side to side

move head

extension

flexion

hyper extension

move head to front

move head from all the way in the front to its OG spot

move head backwards

move body torso

hyperextension

flexion

extension

move torso all the way to front

move torso all the way back

move torso back to OG spot

move legs/arms

flexion leg

flexion arm

move to all the way in front

move all the way to back

extension leg

extension arm

hyper extension

move arm all the way to back

get leg to og spot

arm to og spot

arm moves

abduction

adduction

circumduction

move hand circular

move arms up

click to edit

move head

rotation

move leg

lateral rotation

move leg to side; ballerina

medial rotation

toes face middle/front again

finger moves

leg moves

jaw moves

sole moves

jaw moves 2

palm moves

thumb and index connect

oppostion

elevation mandible

closed mouth

depression mandible

open mouth

protraction of mandible

retraction of mandible

jaw super out

jaw noy super out but in

inversion

eversion

leg to inside

leg to outside

dorsifelxion

plantar flexion

go up

go down

supination

pronation

palm faces up

palm faces down

structure/organization levels of muscles

muscle(organ)

hundreds/thousands of muscle cells+connective tissue wrappings, blood vessels, nerve fibers; covered externally via epimysium

fascicle(portion of muscle)

discrete bundle of muscle cells; segregated from rest of muscle via connective tissue sheath; surrounded by perimysium

muscle fiber(cell)

elongated, multinucleate cell; striated

myofibril(complex organelle of bundles of myofilaments)

rodlike contractile elements, occupy most of cell volume

sarcomere(segment of myofibril)

contractile unit, composed of myofilaments

myofilament, filament(extended macromolecular structure)

contractile myofilaments= thick/thin; thick has myosin molecules; thin has actin molecules

sliding filament theory

impulse travels from nerves to muslce

impulse reaches motor neuron, acetylcholine is released

impulse is then triggered on muscle due to acetylcholine

impulse then travels from muscle to plasma membrane, the sarcolemma, by the T-Tubules

as impulse travels down T-Tubule, so calcium gets released by the sarcoplasmic reticulum

The Ca binds to troponin on actin

when Ca binds to troponin, it turns to tropomyosin, which makes myosin binding site accessible

it then creates a cross-bridge; a connection between myosin filaments and actin

after cross bridge forms, the phosphate is released

phosphate release triggers actin and myosin to slide and ADP is released; called power stroke

when ATP connects to myosin, it finally releases the Actin

Then ATP becomes ADP and phosphate

hydrolysis pushes myosin head down; ready for another muscle contraction

the Ca is pumped back into interior

so, the tropomyosin covers the myosin binding site again

Finally, the actin and myosin filaments slide to their OG spots=relaxed

disorders

fibromyalgia

chronic inflammation muscles, conn. tissues covering tendons, capsules near joints

hernia

protrusion of organ through cavity of wall; heavy lifting/obesity=causes

myalgia

muscle pain resulting from any muscle disorder

myofascial pain syndrome

pain caused by tightened band of muscle fibers; twitch when skin is touched

myopathy

any disease of muscle

myotonic dystrophy

form muscular dystrophy that is less common than DMD; gradual reduction of muscle mass/control of skeletal muscles

RICE

rest, ice, compression, elevation; for pulled muscle, tendons

strain

pulled muscle; irritate/painful range; overuse/abuse

spasm

sudden, involuntary twitch in smooth/skeletal muscle;

tetanus

sustained contraction of a muscle; acute infectious disease due to aneerobic bacterium

charley horse

painful muscle spasm; due to stretching / tear muscles