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Lucy Herrera Period. 5, Muscular System, : - Coggle Diagram
Lucy Herrera Period. 5, Muscular System
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Disorders
Myasthenia Gravis: : Neuromuscular disorder that blocks neurotransmitter
Causes: age, autoimmune, ossible tumore of the thymus
Symptoms: muscle weakness, shortness of breath, facial paralysis
Treatment: No known cure, medications, thymectomy
Cerebral Palsy: Spastic paralysis causing muscle weakness
Causes: Brain injury or abnormalities, hypoxia, brain infections
Symptoms: mild to severe, delayed development, seizures
Treatment: No known cure, medication for symptoms, physical therapy
Fibromyalgia: Muscle pain
Causes: Physical trauma, abnormal pain response, infection
Symptoms: muscle pain, tender joints, joint pain
Treatment: physical therapy, excersise, massage
Myositis: Inflammation of the muscles
Causes: autoimmune, infection, muscle trauma
Symptoms: muscle weakness, swelling, tenderness
treatments: medication, antibiotics, reduce inflammation
Muscle coverings: Connective Tissue Sheaths - each skeletal muscle as well as each muscle fiber is covered in connective tissue.
- Support cells and reinforce whole muscle
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Sliding filament theory of muscle contraction: Contractions: activation of cross bridges to generate force. Shortening occurs when tension generated by cross bridges on the thin filaments exceeds the force opposing shortening. And in the relaxed state, Thin and Thick filaments overlap only slightly at the ends of A bands.
Sliding Filament Model of Contraction states that during contraction thin filaments slide past thick filaments causing actin and myosin to overlap more.
- neither thick or thin filaments change in length, just overlap more
Action potential in a muscle fiber: resting sarcolemma is polarized meaning of voltage exists across membrane.
- Inside of cell is caused by changes in electrical charges
Depolarization: Generation and progagation of an Action Potential (AP)
- If end plate potential causes enoght changes in membrane voltage to reach critical levels called threshold, voltage gated Na+ channels in membrane will open
- large influx of Na+ through channels into cell trigger AP that is Unstoppable and will lead to muscle fiber contraction
- AP spreads across sarcolemma from the voltage-gated Na+ channels to next one in adjacent area causing the area to depolarize
Repolarization: Restoration of resting conditions
- Na+ voltage-gated channels close, and voltage-gated k+ channels open
- K+ efflux out of cell rapidly brings cell back to initial resting membrane voltage
Generalization of end plate potential: ACH released from motor neuron binds to ACH receptors on sarcolemma
- Causes chemically gated ions gated ion channels on sarcolemma to open
- Na+ diffuses into muscle fiber
Sacromere: Sallest contractile unit (functional unit) of muscle fiber. Contains A band with half of an Iband at each end. Consists of an area between Z discs. Individual sarcomeres align end to end along myofibril, like baxcars of trains.
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