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Muscular System (Functions (movement, control passages, heat production,…
Muscular System
Functions
movement
control passages
heat production
communication
stability
Structures
1 muscle
perimysium
fascicle
epimysium
bundles of fibers
1 fiber
myofibril
myofilaments
myosin
actin
Types of muscles
Cardiac
characteristics
striated
involuntary
location
the heart
function
pumps blood through circulatory system
Smooth
characteristics
smooth
involuntary
Location
stomach
intestinal walls
arteries
function
expels urine from your urinary bladder
moves food through the gastrointestinal tract
regulates the flow of blood in the arteries and air through the lungs
sends babies out of the uterus
Skeletal
characteristics
striated
voluntary
location
around bones and other muscles
functions
contracts and extends when your brain tells them to
aids in the movement of your body
Muscular system concept map
anterior muscles
muscles of head
zygomaticus
raises corners of mouth
orbicularis oris
closes and protrudes lips
sternocleidomastoid
flexes neck; rotates head
masseter
closes jaw
orbicularis oculi
blinks and closes eyes
Frontalis
raises eyebrows
platysma
pulls corner of mouth inferiorly
temporalis
closes jaw
buccinator
compress cheeks, as in whistling and sucking
muscles of arm
biceps brachii
flexes elbow and supinates forearm
flexor carpi ulnaris
flexes wrist and abducts wrist
flexor carpi radialis
flexes wrist and abducts hand
flexor digitorium superficiali
flexes wrists and fingers
deltoid
abducts arm
muscles of trunk
pectorals major
adducts and flexes humerus
rectus abdominis
flexes vertebral column
external oblique
flexes and rotates vertebral column
muscles of thigh and leg
tibialis anterior
dorsiflexes and inverts foot
sartorius
proximal tibia
hamstring
flex knee extends hip
iliopsoas
flexes hip
adductor muscles
adduct thigh
levels of skeletal muscles
myofilament
contractile myofilaments are of two types thick and thin. thick filaments contain bundled myosin molecules; thin filaments contain actin molecules. the sliding of the thin filaments past the thick filaments produces muscle shortening. elastic filaments provide elastic recoil when tension is released and help maintain myofilament organization
sarcomere
a sarcomere is the contractile unit, composed of myofilaments made up of contractile proteins
myofibril
myofibrils are rodlike contractile elements that occupy most of the muscle cell volume. composed of sarcomeres arranged end to end they appear banded, and bands of adjacent myofibrils are aligned
muscle
a muscle consists of hundreds to thousands of muscle cells, plus connective tissue wrapping, blood vessels, and nerve fibers
covered externally by the epimysium
muscle fiber
a muscle fiber is an elongated multinucleate cell; it has banded appearance
surrounded by endomysium
fascicle
a fascicle is a discrete bundle of muscle cells, segregated from the rest of the muscle by a connective tissue sheath
surrounded by perimysium
posterior muscles
muscles of arm
tricep brachii
extends elbow
extensor digitorium
extends fingers and wrist
extensor carpi radialis
extends wrist and abduct hand
muscles of trunk
trapezius
extends neck and adducts scalpula
latissimus dorsi
extends and adducts humerus
erector spinae
extends back
muscles of thigh and leg
soleus
plantar flexes foot
gastrocnemius
plantar flexes foot and flexes knee
hamstring
flex knee,extends hip
gluteus maximus
extends hip
3 types of muscles tissues
skeletal muscle
cells are long, cylindrical , parallel and multinucleate
voluntary subject to conscious control
attached by tendons to bones
striated visible bonding
cardiac muscle
has striations
involuntary
joined to another cells at intercalated disc
forms heart wall
cells are long, cylindrical , branched, has single central nucleus
smooth muscle
found mainly in hollow walls of organs and eyes
involuntary
spindle shaped cells with single central nucleus
has no striations
muscle contraction
steps of muscle contraction
step 4 : electrical current is generated and is carried along sarcolemma, causes action potential
step 3 : this causes receptors to change shape, and opens Na+ channels in sarcolemma
steps 2 : ach diffuses cicross synaptic cleft, and binds with receptors on motor end plate of the muscle cell
step 1: nerve impulse reaches synaptic end bulbs and causes synaptic vesicles to fuse with neurolemma and release ach
sliding filament theory steps
step 5 : this action is repeated many times powered by ATP
step 4 : myosin head moves toward m line of sarcomere,pulling actin filaments past myosin
step 6 : Z lines get closer together as actin and myosin filaments slide past each other, and sarcomeres shorten H zone disasters shortening the entire myofibril
step 2 : Ca++ binds to actin myofilament, exposing the myosin binding site
step 3 : myosin attaches to actin, forming actin, myosin crossbridges
step 1 : nerve impulse or action potential travels down sarcolemma and into T-tubules, causing sarcoplasmic reticulum to release Ca++ into sarcoplasm
body movement
eversion
turn sole of of foot laterally
hyperextension
extension beyond 180 degrees
adduction
movement of limb toward the midline
rotation
movement of a bone around a longitudinal axis
abduction
movement of limb away from midline
plantar flexion
pointing toe
dorsiflexion
lifting the superior surface of foot towards shin
extension
movement that increases angle of joint
supination
forearm rotates laterally so palm faces anteriorly
circumduction
proximal end of a limb is stationary and the distal end moves in circle
flexion
movement that decreases angle of joint
pronation
forearm rotates. medially so palm faces posteriorly
inversion
turn sole of foot medially
opposition
movement of thumb to touch tips of other fingers