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Muscular System Katherine Contreras Period 6 - Coggle Diagram
Muscular System Katherine Contreras Period 6
Neuromuscular junction
synapse-connection between nerve with muscles and other organs
Axon-long portion of nerve, releases a chemical called neurotransmitter
synaptic cleft-gap between neuron and sarcolemma
acetylcholine-neurotransmitter for skeletal muscle
synaptic end bulb-found in axonal terminal(contains synaptic vesicles)
motor end plates-region across synaptic cleft from the synaptic end bulb( on muscle fibers)
3 types of muscles & their functions
skeletal Muscles
organs that attach and protect the skeleton
responsible for most of the body's movement
skeletal muscle fibers are the longest cells
have striations and voluntary
many nuclei
cardiac Muscles
only found in the heart
cardiac cells are striated and involuntary
single nucleus
Smooth Muscles
made up of elongated cells
has no striations, involuntary
found in walls of hollow organs
function: push fluids and other substances through internal body channels
single nucleus
Major functions of the muscular system
Produces Movement
Maintains posture and body positions
Generate Heat
Stablilize joints
Sliding filament theory of muscle contraction
contraction signal in the brain
Brian sends signal to the motor neuron
acetylcholine gets to recpetors and sends a signal to the muscle sarcolemma , causing an impulse
the impulse travels down the membrane and into the transverse tubules
the transverse tubules causes the calcium to be released
the calcium then binds to actin and causes it to change shape and become larger
that leads to them binding together with multiple actin myofilaments
the change in shape allows the myosin heads to form cross bridges, connecting the actin myofilaments and the myosin
the ATP energy is then used to create a "power stroke"
After, the actin slides and pulls it causes a muscle contraction
Action potential in a muscle fiber
Sodium ions enter the muscle fiber, and an action potential spreads quickly
The action potentials travel from the surface of the muscle cell along the membrane of T tubules that penetrate into the cytosol of the cell.
This depolarization initiates an action potential on the muscle fiber cell membrane (sarcolemma) that travels across the surface of the muscle fiber.
action flexion of forearm at the elbow
insertionis radial tuberiosity of radius
Muscle coverings
perimystium: extend inward and surrounds bundles of skeletal muscle
aponeuroses: when muscles are connected to each other
fascia: layers of connective tissue that separate and surround the muscle
tendons: extend beyond the ends of the muscle
epimysium: make fascia blend and goes around each skeletal muscle
endomysium: covers each muscle cell
Skeletal Muscles
Neck
Sternocleidomastoid
trapezuis
Shoulder
deltoid
Back
rhomboid major
teres major
infraspintus
latissmimus dorsi
arms
triceps brachii
branchiordalis
flexor carpiradials
extensor
entensor carpireadialis long
Legs
sartorius
graccilis
adductor magnus
rectus medials
gastrocnemius
fibularis longus
extensor digitorium
tibialius enterior
vastus laterialis
vastus medials
Dorsal Legs
gastrocnemius
soleus
gracilis hamstrings
adductor magnus
biceps femoris
fibularis longus
calcaneal tendon
Muscles of the Face
Sarcomere
I band: the lighter striation that contains thin filaments
H zone: lighter section within the A band
M line: the line in the middle of the H zone and A band
A band: darker striation that has thin and thick filaments overlapping each other