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Muscular System Emerson Brown Period 4 (Body Movement (angular movements…
Muscular System Emerson Brown Period 4
Functions of the Muscular System
Stability: muscle tendons stretch over joints
Mobility: allowing movement; muscles contracting
Posture: helps keep body in the correct position
Circulation: heart- pumps blood throughout the body
Respiration: the diaphragm muscle controls breathing
Digestion: muscles in the GI tract
Three Types of Muscle Tissues
Skeletal: attach to and cover skeleton
activated by reflexes
responsible for overall body movement
adaptable
exerts power; adaptable
Cardiac: ONLY in the heart; constitutes bulk of heart walls
cells are striated, but not voluntary
contract without stimulation from nervous system
Smooth Muscle: found in walls of hollow organs
located in stomach, urinary bladder, and respiratory
regulates passage of substances
NOT voluntary control
Body Movement
Inversion and Eversion
Elevation and Depression
pronation and supination
rotation
angular movements
flexion
extension
hyperextension
abduction and adduction
circumduction
gliding movements
back and forth, side to side
opposition
Protraction and Retraction
Dorsiflexion and Plantar
Muscle Contraction
sliding filament theory
during contraction, thin filaments slide past thick ones so that actin and myosin filaments overlap
neither thin nor thick filaments change length during contraction
myosin heads on thick filaments latch to thick filaments
cross bridge attachments form and break during contraction
Muscle Names
Shoulder
trapezius
deltoid
Arm
triceps brachii
biceps brachii
Neck
sternocleidomastoid
Forearm
brachioradialis
flexor carpi radialis
iliopsas
Thorax
pectoralis minor
pectoralis major
serratus anterior
Abdomen
rectus abdominus
internal oblique
external oblique
Thigh
rectus femorus
vastas lateralis
vastas medialis
sartorius
adductor longus
gracilus
Leg
fibularus longus
extensor digitorum longus
fibialis anterior
extensor digitorum brevis
gastrocnemius
soleus
Structural and Organizational Level
Muscle
hundreds of thousands of cells, connective tissue wrappings, blood vessels, and nerve fibers
covered entirely by epimysium
Fascicle
bundle of muscle cells, separated from the rest by connective tissue sheath
surrounded by perimysium
Muscle fiber (cell)
elongated multi nucleate cell; banded, striated, appearance
surrounded by endomysium
Myofibril
rodlike contractile elements that occupy most of muscle cell volume; sarcomeres arranged end to end; bands of adjacent myofibrils are aligned
Sarcomere
contractile unit; composed of myofilaments made up of contractile elements
Myofilament (filament); two types
thick: contain bundles of myosin molecules
thin: contain actin and other proteins
the sliding of thin filaments past thick filaments leads to muscle shortening
Elastic filaments provide elastic recoil when tension is released; help maintain myofilament organization
Disorders associated with Muscular System
Shin Splits
medial tibial stress syndrome
painful inflammation of the muscles, tendons, and connective tissue
treated with rest and ice
Hernia
abnormal protrusion of an organ or tissue
inguinal and umbilical hernias: hernia penetrates the muscle wall, but not the skin
Tennis elbow
lateral epicondylitis
tenderness due to overuse of tendon
aggravated when muscles contract to extend hand at wrist
Charley Horse
painful muscle spasm
results from stretching or tearing a muscle, muscle strain, or contusion (bleeding in the muscle)
Ruptured calcaneal tendon
common in recreational sports
rupture is accompanied by abrupt pain
gap is seen just above the heel; calf buldges
plantar flexion is weak or impossible; dorsiflexion is exaggerated
Fibromyalgia
a group of conditions involving chronic inflammation of muscle
Myalgia
muscle pain which results from any muscle disorder
Muscle fatigue: state of physiological inability to contract
ionic imbalances
increased inorganic phosphate
decreased ATP and increased magnesium
decreased glycogen
