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Muscular System - Sandra Cortez P.1 - Coggle Diagram
Muscular System - Sandra Cortez P.1
Disorders associated with the Muscular System
c. Myasthenia Gravis
Causes/risk factors
Autoimmune, possibly tumor of the thymus, age and
is more common in women
Symptoms
Muscle weakness, shortness of breath, swallowing and chewing difficulty, facial paralysis, drooping eyelids, double vision and anxiety disorder
Description
Eyebrow and the corner of the mouth droop, there is also smoothing out of the forehead
Treatment options
No known cure
, medications, thymectomy, eye patch for double vision
Neuromuscular disorder that blocks neurotransmitters
d. Cerebral Palsy
Causes/risk factors
Brain injury or abnormality, hypoxia during premature birth, brain infections, head injury and bleeding in the brain
Symptoms
Mild to severe, delayed development, muscle lightness, abnormal galt, joint contracture, paralysis and seizures
Description
Spastic, athetoid, ataxic, rigidly and tremor
Treatment options
No cure
, medication for symptoms, physical therapy, surgical intervention
Spastic paralysis causing muscle weakness
b. Fibromyalgia
Causes/risk factors
Exact cause is unknown but is more common in women
so possibly: physical trauma, abnormal pain response, sleep disturbances and infection
Symptoms
Muscle pain, tender points, joint pain, stiffness, fatigue, depression and insomnia
Description
Chronic headaches, pain/fatigue, various complaints, weight gain and sensitivity
Treatment options
Physical therapy, exercise regimen, massage, relaxation techniques, medication and lifestyle change
Muscle pain
e. Myositis
Causes/risk factors
Autoimmune, infection, medication induced and muscle trauma
Symptoms
Muscle weakness, swelling, tenderness, muscle damage, myalgia, rash and fatigue
Description
Red appearance, rash like and there is swelling
Treatment options
Medication, antibiotics or reducing inflammation
Inflammation of the muscle
a. Muscular Dystrophy
Muscle weakness and atrophy
Symptoms
Mental retardation, muscle weakness, eyelid drooping, loss of strength, muscle atrophy and delayed motor skills
Causes/risk factors
Genetic & type various on mutation: duchenne, becker, myotonia congenital, myotonic
Treatment options
No known cure
, muscle therapy, medication, surgery to improve function and physical activity (as much as possible)
Description
Shoulder/arms are held back awkwardly when walking, knees bend, walk on toes and poor balance
3 types of muscles & their functions
Smooth (lacks striations & is involuntary)
Movement of viscera peristalsis, vasoconstriction
Found in: the walls of hollow viscera/blood vessels, contracts and relaxes
slowly
;
single unit
type is self-exciting (rhythmic), & lacks transverse tubules
Elongated w/tapered ends
Cardiac (has striations & is involuntary)
Pumping action of the heart
Found only in: the wall of the heart, the network of cells contracts as a
unit
; self-exciting (rhythmic), & has a
well-developed
transverse tubule system;
intercalated discs
separating adjacent cells
Branching
Skeletal (has striations & is voluntary)
Movement of bones at joints, maintenance of posture
Found in: skeletal muscles, contracts and relaxes
rapidly
when stimulated by a motor neuron, & has a
well-developed
transverse tubule system
Sliding filament theory of muscle contraction
b. The binding causes the head to bend by pulling on the actin filament causing it to move toward the center of the sarcomere
c. The head releases and attaches to the next binding site on the actin pulling the site toward the center
a. A myosin head attaches to a binding site on the actin filament forming a cross-bridge
d. As this occurs again and again the filaments increase their overlap and the sarcomere shortens from both ends
e. When many sarcomeres shorten at the same time, the muscle fibers shorten (contract)
Muscle coverings
(connective tissue coverings)
The
perimysium
extends inward from the
epimysium
; it surrounds bundles of skeletal muscle fibers called
fascicles
within each muscle
Each muscle cell fiber is covered by a connective tissue layer called
endomysium
Fascia (dense C.T)
blends w/ the
epimysium
(the layer of connective tissue around each skeletal muscle)
[Fascia] surround and separate each muscle, this C.T extends beyond the ends of the muscle & gives rise to tendons that are fused to the periosteum of bones
[Aponeuroses] muscles connected to each other by broad sheets of C.T
Sarcomere
(the funcional unit of the muscle cell)
Myofibrils are made up of many units called sarcomeres that join end to end
(Z line) the boundary of the sarcomere
(I bands) thin light bands, made up of actin filaments that are anchored to the z lines
(A bands) dark bands, made up of overlapping thick and thin filaments
(H zone) the center of the A band
Action potential in a muscle fiber
Stimulus for contraction (carries the action potential)
Acetylcholine
Released into the synaptic cleft, in response to an impulse in the motor neuron which then stimulates the muscle fiber
Upon receipt the (SR) releases stored calcium to the cytosol of the muscle fiber, the high concentration interacts w/ the troponin and tropomyosin molecules
Stored in the synaptic vesicles at the distal end of the neuron
Which expose the myosin binding sites on the actin filament, cross bridges form linking thick and thin filaments leading to a contraction
Produced in the motor neuron
Relaxation of the muscle (breaks down action potential)
Acetylocholinesterase
ATP binds to myosin heads - the linkage between myosin and actin are broken
The actin returns to its original position and the muscle relaxes
Calcium is returned to the (SR) using ATP as an energy source
Troponin and tropomyosin molecules block the interaction between myosin and actin filaments
In the motor end plate, acetylcholinesterase rapidly decomposes
Names of all of the skeletal muscles (including the facial muscles)
Facial muscles
Frontalis, temporalis, orbital oculi, zygomaticus, orbicularis oris and masseter
Upper limbs (arms)
Deltoid, triceps/biceps brachii, brachioradialis, flexor carpi radialis, extensor carpi radialis longus and palmaris longus,
Abdominal region
Rectus abdominis, external oblique, pectoralis major and seeatus anterior
Lower limbs (legs)
Vastus femoris, rectus femoris, vastus medialis, tensor fascia latus, tibialis anterior, soleus, fibularis longus and extensor digitorum longus
Pubic/thigh region
Illopsoas, pectineus, pectineus, adductor longus and gracilis
Upper/lower back
Trapezius, infraspinatus, tres major, rhomboid major, latissimus dorsi, gluteus medius and the gluteus maximus
Neuromuscular junction
An electrical impulse reaches the end of an axon (of a motor neuron)
Synaptic vesicles release neurotransmitters into the synaptic cleft (the gap between the membranes of the neuron and muscle fiber)
Motor end plate:
the muscle fiber membrane in this area contains a specialized region in which the sarcolemma is tightly folded
(contains specific receptors for the neurotransmitters)
The neurotransmitters diffuse across the cleft & bind to the motor end plate
The cytoplasm of the distal end of the motor neuron contains numerous mitochondria and synaptic vesicles storing neurotransmitters
This stimulates the muscle fiber to contract
(synapse between a motor neuron & a muscle fiber that it regulates)
Major functions of the muscular system
Maintaining body posture
Regulating body temperature
Supporting soft tissues and our weight
Stabilizing joints
The muscular systems aids in..
Mobility