Chapter 8: Muscular System

Actin

Protein in a muscle fiber that forms the thin filaments that slide between thick filaments of the protein myosin, contracting muscle fibers

Myofibril

Contractile fiber in striated muscle cells

Rigor Mortis

Several hours after death skeletal muscle partially contract and become rigid, fixing the joints in place

Insertion

Relatively movable end of skeletal muscle 

Origin

Relatively immovable end of skeletal muscle 

Myo- 

Muscle

Hypertrophy

Forcefully exercised muscles enlarge

Neuron

Generators and conductors of impulses 

Voluntary

Conscious

Nonstriated

Without lines

Fascia 

Sheet of dense connect tissue that separates individual muscles and helps hold them in position

Neurotransmitter Junction

Motor neurons stimulate muscle fibers to contract: Synapse between a motor neuron and a skeletal muscle fiber

Tendon

Cordlike or bandlike mass of dense connective tissue that connects a muscle to a bone

Muscle Fiber

Elongated, cylindrical cells that make up skeletal muscles. They are responsible for generating force and movement in the body

Atrophy

A condition where muscles gradually weaken and shrink

Myosin

Protein in a muscle fiber that forms the thick filaments that pull on the thin filaments of the protein actin, contracting muscle fibers

Striated

With lines

Involuntary

Unconsious