Please enable JavaScript.
Coggle requires JavaScript to display documents.
Muscular System Yarely Franco Period 2 - Coggle Diagram
Muscular System Yarely Franco Period 2
3 Types of Muscles
Skeletal Muscle:
Located in skeletal muscles, many nuclei, striations present, & its voluntary. Its function is to move bones at joints & maintain posture.
Cardiac Muscle
: Located only in the heart & is involuntary. Consists of a branching site, a single nucleus, striations present, & intercalated discs.
Smooth Muscle
: Located in walls on hollow internal organs. Striations are absent, single nucleus, involuntary, & contracts slowly.
Names of all Skeletal Muscles
Biceps Brachii
Sternocleidomastoid
External Oblique
Extensor Digitorum:
Deltoid
Pectoralis Major
Sliding filament theory of muscle contraction
head then releases, and attaches to the next binding site on the actin, pulling this site toward the center
filaments increase their overlap, and the sarcomere shortens from both ends
binding causes the head to bend, pulling on the actin filament, and moving it toward the center of the sarcomere
ATP breakdown causes the heads to return to its regular position
a myosin head attaches to a binding site on the actin filament, forming a cross-bridge
Muscle Coverings
Endomysium
: Each muscle cell (fiber) is covered by a connective tissue layer
Perimysium
: extends inward from the epimysium; it surrounds bundles of skeletal muscle fibers, called fascicles, within each muscle
Fascia blends with the
epimysium
, the layer of connective tissue around each skeletal muscle
Major Functions
Provide movement
Provide protection for bones and internal organs
Produce heat
Blood circulation
Neuromuscular Junction
Step 1:
An action potential travels the length of the axon of a motor neuron to an axon terminal
Step 2:
Voltage gated calcium channels open and calcium ions diffuse into the terminal
Neuromuscular junction
: a synapse between a motor neuron and
a muscle fiber that it regulates
Step 3:
Calcium entry causes synaptic vesicles to release acetylcholine via exocytosis.
Step 4:
Acetylcholine diffuses across the synaptic cleft & binds to acetylcholine receptors, which contain ligand gated cation channels.
Step 5
: Ligand-gated cation channels open.
Step 6:
Sodium ions enter the muscle fiber & potassium ions exit the muscle fiber. The greater inward flux of sodium ions relative to the outward flux of potassium ions causes the membrane
Sarcomere
Sacromeres: myofibrilis made up of many units joined end to end
Muscle contractions result sarcomeres to shorten & pulling of muscle
A sacromere extends from one Z line to the next
Disorders
Myasthenia Gravis
: Neuromuscular disorder that blocks neurotransmitters.
Causes & risk factors:
age, autoimmune, & most common in women.
Syptoms
: double vision, facial paralysis, & drooping eyelids. There is known cure.
Fibromyalgia:
Muscle pain. The causes & risk factors are infection, physical trauma, & sleep disturbances. Symptoms are depression, stiffness, & joint pain. Massages, physical therapy, & lifestyle may help treat it.
Cerebral Palsy:
spastic paralysis causing muscle weakness.
Causes/Risks
: Head injury, bleeding in brain, & abnormal gait
Symptoms
: seizures, paralysis
No known cure
Muscle Dystrophy
: Muscle weakness & atrophy. The causes risk factors are gentics, myotonic, & duchenne. There is no known cure.
Myositis
: inflammation of the muscle Causes/Risks: Muscle trauma, infection, autoimmune
Symptoms
: Rash, fatigue, swelling
Treatment
: medication, antibiotics
Action potential in a muscle fiber
The action potential generated by depolarizing the endplate membrane of muscle cells increases the calcium ion concentration in muscle plasma
Troponin binds a sufficient number of calcium ions to cause a conformational change in the troponin molecule