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