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Muscular System Karla Diaz P.2:<3: - Coggle Diagram
Muscular System Karla Diaz P.2:<3:
Major Functions
digestion
circulation
posture
childbirth
urination
3 types of muscles & their functions
Smooth muscle:
-muscle that shows no cross stripes under microscopic magnification
-narrow spindle-shaped cells with a single, centrally located nucleus
-contracts slowly and automatically
cardiac muscle:
-found only in the heart
-it possesses contractile units known as sarcomere
-not under voluntary control
Skeletal muscle:
-attatched to bones by tendons, and they produce all the movements of body relation to each other
-under voluntary control
-striated; its long, thin, multinucleated fibers are crossed with a regular pattern of fine red and white lines
Skeletal muscles
Muscles of face
Temporalis: closes jaw
Buccinator: compresses the cheek
Orbicularis oris: closes lip
Frontalis: raises the eyebrows
Oribicularis: closes eye; produces blinking;squinting; pulls eyebrows ineeriroly
Masseter; prime mover of jaw closure
stemodeidomastoid; rotation of the head to the opposite side
muscle man
sternoclaidomomastid
deltoid
trapezius
pectoralis major
internal oblique
lliopsoas
sartorius
flexor carpi ulnaris
flexor carpi radialis
brachioradialls
biceps brachii
Sacromere
-joined end to end
-extends from one z line to the next
-each sacromere is composed of two main protein filaments(actin and myosin.
-actin and myosin are responsible for muscle contraction
Neuromuscular junction
neuromuscular junction is a synapse between a motor neuron and a muscle fiber that it regulates
the steps to neuromuscular junction are:
1st step: an action potiental travels the length of the axon.
2nd Step: voltage gated calcium channels open and calcium ions diffuse into the terminal.
3rd step: calcium causes synaptic vesicles to relase acetylcholine
4th step: Acetycholine diffuses across the synaptic cleft and binds to acetylcholine receptors that has ligand gated cation channels
5th step: When the ligand-gated cation channels open sodium ions enter and then potassium ions exit the muscle
6th step:Sodium ions shown here in red enter the muscle fiber. Potassium ions shown here in blue exit the muscle fiber the greater inward flux of sodium ions relative to the outward flux of potassium ions causes the membrane potential to become less negative
7th step: when the membrane potential reaches a threshold value an action potential propagates along the sarcolemma. One acetylcholine gets away from the synapse to acetylcholine is broken down by enzyme
Sliding filament theory of muscle contraction
explains the mechanism of muscle contraction based on multiple proteins that slide past eachother to generate movement
Action potential in a muscle fiber
Muscle coverings (TB fig. 8.1)