Please enable JavaScript.
Coggle requires JavaScript to display documents.
Muscular System Aubrey Menchaca P : 5 - Coggle Diagram
Muscular System Aubrey Menchaca P : 5
Major functions of the Muscular System
Excitability
- Ability to recieve and respond to stimuli
Contractility
- Ability to shorten forcibly when stimulated
Extensibility
- Ability to be stretched
Elasticity
- Ability to recoil to resting length
movement, support, and blood circulation
3 types of muscles and their functions
Cardiac
Contracts the heart to pump blood and only covering walls of the heart
Skeletal
Made up of different tissues and has three features : nerve and blood supply, connective tissue sheaths, and attachments. Attaches to bones and allows movement
Smooth
usually covering the walls of organs and changes shape to facilitate bodily functions
Sarcomere
Straitions - stripes formed from repeating series of dark and light bands along length of each myofibril
A bands - dark regions H zone - Lighter region in middle of dark A band
Myofibrils - densely packed, rodlike elements
I band - Lighter regions Z disc - coin shaped sheet of proteins on midline of light I band
Neuromuscular junction
Voltage-gated calcium channels open, calcium enters motor neuron
Calcium entry causes release of Ach neurotransmitters into synaptic cleft
Action potential arrives at axon terminal
Ach diffuses across to Ach receptors on sarcolemma
Ach binds to receptors, opens gates, allowing sodium to enter resulting in end plate potential
Acetycholinesterase degrades Ach
Disorders associated
Cerebral Palsy
- Spastic paralysis causing muscle weakness and can be caused by brain injury or abnormality
Myasthenia Gravis
- Neuromuscular disorder that blocks neurotransmitters and there is no known cure
Myositis
- Inflammation of the muscles and can be medication induced or due to infection
Fibromyalgia
- Muscle pain caused by physical trauma, abnormal pain response, or sleep disturbance
Muscular Dystrophy
- Muscle weakness and atrophy which can be genetic, Duchenne, and Emery-Dreifuss
Muscle Coverings
Perimysium
- Fibrous connective tissues surrounding fascicles ( groups of muscle fibers )
Endomysium
- Fine aerlor connective tissue surrounding each muscle fiber
Epimysium
- Dense irregular connective tissue surrounding entire muscle ; may blend with fascia
Action potential in a muscle fiber
Troponin binds number of calcium ions which causes change in troponin molecule and that is transmitted to myosin
increases the calcium ion concentration in muscle plasma
Depolarizes the endplate membrane of muscle cells
Sliding filament theory of muscle contraction
During contraction, thin filaments slide past thick filaments, causing actin and myosin to overlap more
Shortening occurs when tension generated by cross bridges on thin filaments exceeds forces opposing shortening
Contraction - The activation of cross bridges to generate force
Skeletal Muscles
Zygomaticus
Orbicularis oculis
Trapezius
Sternohyoid
Masseter
Temporalis
Frontalis
Orbicularis oris
Biceps brachii
External oblique
Rectus Sbdomis
Deltoid
Pectoralis major
Gastroncnemius
Abbductor
Sartorius
Rhomboid
Triceps brachii
Gluteus maximus
Lastissimus dorsi
Soleus
Vastus medialis