Muscular Anatomy Muscular

Abduction

moving a limb away from the midline of the body

Adduction

moving a limb toward the midline

Acetylcholine

specific neurotransmitter that stimulates muscles

Actin

protein that the thin filaments are made of

Action potential

event that occurs when a stimulus of sufficient intensity is applied to a neuron or muscle cell, allowing sodium ions to move into the cell and reverse the polarity

Aerobic respiration

process in which oxygen is used to break down glucose into energy

Antagonist

muscles that oppose or reverse a movement

Axon

long, threadlike extension of a neuron that carries an impulse away from the cell

Circumduction

combo of flexion, extension, abduction and adduction commonly seen in ball-and-socket joints

Contractility

the ability of muscle cells to shorten when stimulated

Elasticity

the ability of muscle cells to recoil and resume their resting length after being stretched

Excitability

the ability of muscle cells to receive and respond to a stimulus; aka responsiveness or irritability

Extensibility

the ability of muscle cells to be stretched

Extension

increases the angle between two bones

Fascicle

a bundle of muscle fibers held together by a perimysium

Flexion

movement than decreases the angle of a joint and brings two bones closer together

Insertion

side of the muscle attached to the movable bone

Muscle fatigue

occurs when a muscle is unable to contract even though it is still being stimulated

Muscle fibers

another name for muscle cells because they are elongated

Muscle tone

a state of continuous partial contraction

Myosin

protein that the thick filaments are made of

Opposition

action by which you move your thumb to touch the fingertips

Origin

side of a muscle attached to the immovable or less movable bone

Pronation

forearm rotates medially so that the palm faces posteriorly

Rotation

movement of a bone around its longitudinal axis; ex- shaking your head no

Sarcolemma

plasma membrane of a muscle fiber

Sarcomere

the smallest contractile unit of muscle; extends from one Z disc the next

Supination

forearm rotates laterally so that the palm faces anteriorly

Tendon

connective tissue that holds muscle to bone

Voluntary muscle

muscle that is subject to conscious control