Chatpter 6 Vocab Muscular System

For Anatomy & Physiology

Muscle Fiber

Single muscle cells

Striated Muscle

Muscle that has obvious stripes

Voluntary

Done with conscious control

Involuntary

Done without conscious control

Endomysium

Encloses a single muscle fiber

Perimysium

Sheath of connective tissue wrapped around a fascicle with bundles of muscle fibers

Fascicle

Bundle of of fibers

Epimysium

Sheath of fibrous, elastic tissue surrounding a muscle covers entire skeletal muscle, & shows attachment

Tendon

Flexible but inelastic cord of strong collagen tissue attaching muscle to bone

Aponeuroses

Sheet of white fibrous tissue that takes place of tendon in flat muscles having wide area of attachment

Smooth Muscles

Has no striations, involuntary, & found mainly in the walls of hollow tube-like organs

Cardiac Muscle

Found in the heart serves has pump , propelling blood through blood vessels to all body tissues

Irritability

Unusual sensitivity to movement or pressure

Contractility

Ability to shorten when an adequate stimulus received (Can contract)

Extensibility

Ability of muscle cells to be stretched without getting damaged

Elasticity

Ability to recoil or resume resting length after stretching

Motor Units

One motor neuron and all the skeletal muscle cells stimulated by that neuron

Axon

Long threadlike part of nerve of cell along which impulses are conducted from cell body to other cells

Axon Terminal

End of axon, bulb shaped end of neuron filled with synaptic vessel

Neuromuscular Junction

Association site of one axon terminal and muscle cell, has a gap, & 3 parts

Synaptic Cleft

Space between nerve & muscle, no contact, & filled with interstitial fluid

Neurotransmitter

Chemical released by neuron upon arrival of nerve impulses

Acetylcholine

Specific transmitter that stimulates skeletal muscle fibers

Action Potential

Movement of ions generate an electrical current

Sarcolemma

Tubular sheath that envelops the fibers of the skeletal muscle

Origin

Attachment to an “immovable” bone or less movable bone like an anchor

Insertion

Attached to movable bone and moves towards the origin

Flexion

Decreasing the angle of the joint, two bones are closer together, usually Hinge Joints

Extension

Increase the angle between the two bones, opposite of flexion, greater than 180

Rotation

Movement of bone longitudinal (Shoulder, Knee, Hip, Atlas) Ball & Socket dens

Abduction

Movement away from the midline (laterally in anatomical position)

Adduction

Movement towards the midline

Circumduction

Combination of flexion, extension, abduction, & adduction; ball & socket & condyloid joints

Dorisflexion

Pointing toes up toward the head

Plantar Flexion

Pointing toes down away from the head

Inversion

Turn sole of foot medially

Eversion

Turn sole of foot laterally

Supination

Forearm rotates laterally so palm faces anteriorly (Palms up)

Pronation

Forearms rotates medially so palm faces posteriorly (Palms down)

Opposition

Move thumb to touch of other fingers on same hand

Prime Mover

Muscle with the major responsibility for a certain movement

Antagonist

Muscle that opposes or reverses a prime mover

Synergist

Muscle that aids prime mover in a movement that prevents unwanted movement

Fixation

Stabilizes the origin of a prime mover (Specialized Synergist)

Erector Spinae

Set of Muscles that straighten and rotate back