Please enable JavaScript.
Coggle requires JavaScript to display documents.
Angela Luna P.2 Muscular System - Coggle Diagram
Angela Luna P.2 Muscular System
Major Functions of Muscular System
produce movement: responsible for all locomotion/ manipulation
maintain posture/ body position
stabilize joints
generate heat as they contract
3 Types of Muscles + 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
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
Neuromuscular 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
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
Names of Skeletal Muscles
HEAD/ FACIAL
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
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
PELVIS
lliopsoas
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
BACK
rhomboid major
latissimus dorsi
HIP
gluteus medius
gluteus maximus
Action Potential in Muscle Fiber
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)
DEPOLARIZATION
generation/ propagation of AP
enough change in membrane voltage to reach critical level= volted-gated Na+ channels open
large influx of Na+ through channels into cell triggers AP; unstoppable and will lead to muscle contraction
AP spreads across sarcolemma causing 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
Muscle Coverings
epimysium: dense irregular CT surrounding entire muscle (outermost)
perimysium: fibrous CT surrounding fascicles
endomysium: fine areolar CT surrounding each muscle fiber (innermost)
Disorders
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
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
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
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
MYOSITIS
inflammation of the muscle
causes/risk factors: autoimmune, infection, medication induced
symptoms: muscle weakness, swelling, rash
treatment: medication, antibiotics, reduce inflammation