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Jessie Castro Per. 2 Muscular System - Coggle Diagram
Jessie Castro Per. 2 Muscular System
Muscle Coverings
.
epimysium: dense irregular CT surrounding entire muscle (outermost)
perimysium: fibrous CT surrounding fascicles
endomysium: fine areolar CT surrounding each muscle fiber (innermost)
Sliding Filament Theory
.
action potential generated, which stimulates muscle
Ca2+ released; binds to troponin, shifting the actin filaments, which exposes binding sites
myosin cross bridges attach & detach, pulling actin filaments toward center (requires ATP)
muscle contracts
Ca2+ removed; shifts actin filaments to original position, blocking binding sites
muscle contraction stops
Neurovascular Junction
.
AP arrives at axon terminal
voltage-gated calcium channels open, calcium enters motor neuron
ACh neurotransmitter releases into synaptic cleft
ACh diffuses across to ACh receptors on sarcolemma
ACh binding to receptors opens gates, allowing NA+ to enter resulting in
end plate potential
Acetylcholinesterase degrades ACh
Sarcomere
.
the smallest contractile unit of muscle fiber
contains A band with half of an I band at each end
align end to end along myofibril
composed of thin actin and thick myosin filaments
3 Types of Muscles and Functions
.
Skeletal: attached to bones and allows movement
Cardiac: responsible for the contractility of the heart to pump blood
Smooth: helps with digestion, nutrient collection, excretion of body toxins
Major Functions of Muscular System
.
produce movement: responsible for all locomotion/ manipulation
maintain posture/ body position
stabilize joints
generate heat as they contract
Action Potential In Muscle Fiber
DEPOLARIZATION
.
generation/ propagation of AP
enough change in membrane voltage to reach critical level= volted-gated Na+ channels
large influx of Na+ through channels into cell triggers AP; unstoppable and will lead to muscle contraction
AP spreads across sarcolemma causing depolarization
END PLATE POTENTIAL
.
ACh released from motor neuron binds to ACh receptors on sarcolemma
causes chemically gated ion channels on sarcolemma to open
Na+ diffuses into muscle fiber, some K+ diffuses outward
results in end plate potential (depolarization)
REPOLARIZATION
.
restoration of resting conditions
Na+ voltage-gated channels close, voltage-gated K+ channels open
refractory period: muscle fiber cannot be stimulated for specific amt. of time until repolarization
completes
Na+ came into cell= pumped back out
K+ flowed out= pumped back into cell
Disorders
MYOSITIS
.
inflammation of the muscle
causes/risk factors: autoimmune, infection, medication induced
symptoms: muscle weakness, swelling, rash
treatment: medication, antibiotics, reduce inflammation
CERBAL PALSY
.
spastic paralysis causing muscle weakness
causes/risk factors: brain injury/ abnormality, hypoxia during, premature birth
symptoms: mild to severe, delayed development, muscle tightness
treatment: no cure, medication for symptoms, physical therapy
MYASTHENIA GRAVIS
.
neuromuscular disorder that blocks neurotransmitters
causes/risk factors: autoimmune, age, more common in women
symptoms: muscle weakness, shortness of breath, swallowing/ chewing difficulty
treatment: medication, thymectomy, no known cure
FIBROMYALGIA
.
muscle pain
causes/risk factors: physical trauma, abnormal pain response, sleep disturbance
symptoms: muscle pain, tender points, joint pain
treatment: physical therapy, exercise regimen, massage
MUSCULAR DYSTROPHY
.
muscle weakness and atrophy
causes/risk factors: genetic, duchenne, becker
symptoms: mental retardation, muscle weakness, eyelid
drooping
treatment: no known cure, physical therapy, medication
Names Of Skeletal Muscles
HEAD
.
temporalis
masseter
epicranius, frontal belly (frontalis)
orbicularis oculi
zygomaticus
orbicularis oris
SHOULDER
trapezius
deltoid
infraspinatus
teres major
NECK
.
platysma
sternohyoid
sternocleidomastoid
.
splenius capitis
splenius cervicis
levator scapulae
rhomboid minor/major
BACK
rhomboid major
latissimus dorsi
THORAX
.
pectoralis minor
pectoralis major
serratus anterior
intercostals
ARM
.
triceps brachii
biceps brachii
brachialis
FOREARM
.
pronator teres
brachioradioalis
flexor carpi radialis
.
extensor carpi radialis longus
flexor/extensor carpi ulnaris
extensor digitorum
HIP
gluteus Medius
gluteus maximus
PELVIS
iliopsoas
pectineus
THIGH
.
tensor fascia lata
sartorious
adductor longus
gracilis
rectus femoris
vastus lateralis
vastus medialis
adductor mangus
hamstrings: biceps femoris, semitendinosus, semimembranosus
LEG
.
fibularis longus
extensor digitorum longus
tibialis anterior
gastrocnemius
soleus