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Muscular System Alejandro Alvarez P2 - Coggle Diagram
Muscular System Alejandro Alvarez P2
Muscles
Cardiac
Structure: branching cells, each with a single nucleus, cells are connected by intercalated discs, striated
Location: found only in the heart
Function: pumps blood through heart and into blood vessels
Smooth
location: walls of hollow internal organs such as digestive tract, blood vessels, and urinary bladder
function: involuntary movements of internal organs
structure: lack striations, spindle shaped
Skeletal
structure: cells are cylindrical long, and striated with many nuclei
Function: move head, trunk, and limbs
Location: Muscles that attach to bones
Skeletal Muscles
Anterior-
Frontalis
orbicularis oculi
zygomaticus
masseter
orbicularis oris
sternocleidomastoid
deltoid
pectoralis major
biceps brachii
brachialis
brachioradials
serratus anterior
external oblique
rectus abdominis
Tensor fasciae latae
sartorius
rectus femoris
adductor longus
vastus medialis
vastus lateralis
gracillis
extensor digitorum longus
fibularis longus
tibialis anterior
gastrocnemius
soleus
Posterior
temporalis
occipitalis
sternocleidomastoid
trapezius
deltoid
teres minor
teres major
triceps brachii
infraspinatus
rhomboid
latissimus dorsi
external oblique
gluteus medius
gluteus maximus
adductor magnus
biceps femoris
gracils
semitendinosus
semimembranosus
gastrocnemius
calcaneal tendon
vastus lateralis
sartorius
fibularis longus
soleus
Major functions of the muscular system
movement
support
protection
heat generation
blood circulation
Sarcomere
Z lines
defines the boundary of the sarcomere in striated muscle and bisects the I-band of neighbouring sarcomeres
H zone
the center of the A band which consists of myosin filaments only
A bands
dak region in a sarcomere which consist of myosin filaments
I bands
light bands which are made up of actin filaments, anchored to z lines
M line
center of H zone, consist of proteins that hold the myosin filaments in place.
Muscle Coverings
fascia
layers of dense connective tissue that surrond and seperate each muscle
tendons
connective tissue that extends beyond the muscle and is fused to the periosteum of bones
aponeuroses
sheet like connective tissue that sometimes connects muscles
Epimysium
the layer of CT around each skeletal muscle
perimysium
extends inward from the epimysium, surrounds the bundles of skeletal muscle fibers (fasicles)
endomysium
covers each muslce fiber
Neuromuscular Junction
motor neuron
carrys messages away from the brain to the rest of the body to allow muscles to move
synapse
each skeletal muscle is functionally not physically connected to the axon of a motor neuron, creating a synapse.
Neurotransmitters
chemicals that the neuron uses to communicate with the muscle fiber, released at the synapse
synaptic vesicles
stores neurotransmitters
motor end plate
a specialized region in the muscle fiber membrane in which the sarcolemma is folded
synaptic cleft
the gap between the membranes of the neuron and muscle fiber.
Sliding filament theory
Muscle Contraction
Step 1
an impuse travels down a motor neuron
Step 2
the motor neuron releases the neurotransmitter acetylcholine.
Step 3
Ach binds to Ach receptors in the muscle fiber
Step 4
the sarcolemma is stimulated An impulse travels over the muscle fiber an deep through the transverse tubules.
Step 5
impulse reaches sarcoplasmic recticulum and calicium is released
Step 6
calcium ions diffuse from SR into cytosol and bind to troponin molecules
Step 7
tropomyosin molecules move and expose specific sites on actin where myosin heads can bind
Step 8
cross bridges form linking thin and thick filaments
Step 9
Thin filaments are pulled toward centerof the sarcomere by pulling of the cross bridges
Step 10
muscle fibers exert force and contraction occurs
Muscle Relaxation
Step 1
acetylcholinerase decomposes acetylcholine and muscle fiber is no longer stimulated.
Step 2
calcium ions are actively transported into the sarcoplasmic reticulum
Step 3
ATP breaks cross bridges without breaking ATP itself
Step 4
Breakdown of ATP cocks the myosin heads
Step 5
Troponin and tropomyosin block the interaction between myosin and actin
Step 6
the muscle fiber is relaxed yet ready to be stimulated again
Muscle Diseases
Cerebral Palsy (spastic paralysis causing muscle weakness)
Symtoms
muscle tightness, paralysis, seizures
causes/ risk factors
bleeding in the brain, head injury, brain infections
treatment
physical therapy, surgical intervention, medication for symptoms
Fibromyalgia (muscle pain)
Causes/risks
physical traua, sleep disturbances, infection
treatment
physical therapy, medication, lifestyle change
symtoms
muscle pain, tender points, fatigue
Muscular Dystrophy (muslce weakness and atrophy)
causes/risk
genetic, myotonic, becker
symptoms
mental retardation, muscle weakness, muscle atrophy,
treatment
no cure, physical therapy, medicatiom
Myasthenia Gravis (neuromuscular disorder that blocks neurotransmitters)
Causes/Risk
more common in women, age, autoimmune
treatment
no known cure, medication, thymectomy
symptoms
muscle weakness, shortness of breath, facial paralysis
Myositis (inflammation of muscle)
causes/risk
autoimmune, infection, muscle trauma
treatment
medication, antibiotics, reduce inflammation
symptoms
muscle weakness, swelling, tenderness,