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Muscular system: Karen B. Ramos P.2 - Coggle Diagram
Muscular system: Karen B. Ramos P.2
Major functions of muscular system:
muscles are organs that generate force that causes all types of movement.
sliding filament theory of muscle contraction:
Explains the mechanism of muscle contraction when protien slides past each other to generate movement. Myosin head attaches to binding site on actin filaments that forms a crossbrigde. Binding causes the head to bend and pull actin filaments which moves forward to center of sarcomere.
action potential in muscle fiber:
muscle contraction begins when the nervous system generates a signal. this signal is called actin potential that travels through a nerve cell called motor neuron.
sarcomere:
many units made up of myofibers
I bands (light bands):
I bands are made up of actin filaments, which are connected to z lines.
A bands(dark bands):
A bands are made up of overlapping myosin (thick) and actin (thin) filaments
In the center of A band is H zone which only consist of myosin fibers.
3 types of muscles:
smooth:
smooth muscles are enlongated cells with tapered ends that lack striations. They have a relatively undeveloped sarcoplasma reticulum. Also contains myosin (thick) and actin (thin) filaments.
cardiac:
only found in heart, consisting of branching, striated cells that inter connect in 3 dimensions. Cardiac muscles are self-exciting (
involuntary).
skeletal:
each muscle fiber is a single, long, cylindrical muscle cells, each fiber responds to stimulation by contracting
names of all skeletal muscles and facial muscles:
myosin (thick) filaments:
in myofibers that consist of protein myosin
actin (thin) filaments:
in myofibers mainly composed of protein actin which also contains troponin and tropomyosin
sarcoplasm:
cytoplasm of a muscle cell (contains many mitochondria and nuclei)
striations:
the organization of filaments produces brands
sacrolemma:
cell membrane of muscle fiber
muscle coverings:
aponeuroses:
muscles that are connected to each other by broad sheets of connective tissues.
fasica:
layers of connective tissue that surround and separate each muscle.
neuromuscular junction:
skeletal muscle fibers contract only when stimulated by a motor neuron. each skeletal muscle fiber is functionally connected to axon a motor of neuron which creates a synapse.