TEAS 7 muscular system

cardiac muscle

heart, involuntary, controlled by ANS

smooth muscle

narrow, spindle cells

single, central nucleus

involuntary

controlled by ANS

found in digestive system, arteries, veins, bladder, eyes

skeletal muscle

attach to bone/skin

movement

voluntary

controlled by SNS

found in tongue, diaphragm, upper esophagus

extensibility

ability of a muscle to be stretched or extended

elasticity

ability of muscle to return to original length when relaxed

excitability

ability to respond to stimulus

contractibility

ability of muscle to shrink or contract

actin

thin filaments, protein forming contractile filaments of muscle cells

myosin

thick filaments, fibrous globulin of muscles that split atp

epimysium

outer layer of muscle

fascicle

bundles that together compose muscles

perimysium

outer layer of fascicle

muscle cell

bundles that make up fascicle

endomysium

outer layer of muscle cell

myofibril

bundle that makes up single muscle cell, where muscle contraction takes place

sacrolemma

membrane covering muscle fiber

tendon

attaches muscle to bone

sliding filament 1st step

actin released from vesicles and travels across synaptic cleft bind receptor on sarcolemma

sliding filament 2nd step

action potential travels to sarcoplasmic reticulum which releases Ca

sliding filament 3rd step

Ca moves troponin and tropomyosin to expose binding sites on actin

sliding movement 4th step

myosin head attaches to actin, forming cross-bridges

sliding filaments 5th steps

myosin propels actin closer to midline, shorten sarcomere, muscle contracts

contraction

actin toward midline, myosin toward z line, cross-bridge, powerhouse

relaxation

troponin, tropomyosin block binding site on actin, Ca causes release