A&P Chapter 6 Vocabulary

Moon Area High School Goodson Honors Anatomy and Physiology

Muscle Fibers

Elongated Muscle Cells

Skeleton Muscle

Muscle composed of cylindrical multinucleate cells with obvious striations; the muscle(s) attached to the body’s skeleton; voluntary muscle.

endomysium

thin connective tissue surrounding each muscle cell.

Perimysium

Connective tissue enveloping bundles of muscle fibers

Epimysium

Sheath of fibrous connective tissue surrounding a muscle.

Fascicle

Bundle of muscle fibers bound together by connective tissues

Tendon

Cord of dense fibrous tissue attaching a muscle to bone

Aponeuroses

Fibrous or membranous sheet connecting a muscle and the part it moves

Smooth Muscles

Spindle shaped cells with one centrally located nucleus and no externally visible striations (bands). Found mainly in the walls of hollow organs

Cardiac Muscle

Specialized muscle of the heart

Sarcolemma

The plasma membrane in muscle cells; muscle husk.

Myofibril

Rodlike bundle of contractile filaments (myofilaments) found in muscle cells.

Sarcomere

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

Myofilament

Filament that constitutes myofibrils. Of two types: Actin and Myosin

Myosin

One of the principal contractile proteins found in muscle; thick filaments.

Crossbridges

Projections of myosin that link thin and thick filaments together during contraction.

Actin

A contractile protein of muscle; thin filaments

Sarcoplasmic Reticulum

A specialized muscle fiber organelle which stores calcium to release upon demand when the muscle fiber is stimulated to contract.

Motor Unit

A motor neuron and all the muscle cells it stimulates

Axon

Neuron process that carries impulses away from the nerve cell body; efferent process; the conducting portion of a nerve cell.

Axon Terminal

A branch ending of a nerve fiber which forms junctions with the sarcolemma of a different muscle cell.

Neuromuscular Junction

Region where a motor neuron comes into close contact with a skeletal muscle cell.

Synaptic Cleft

Fluid-filled gap between nerve ending and muscle cells.

Neurotransmitter

Chemical released by neurons that may, upon binding to receptors of neurons or effector cells, stimulate or inhibit them.

Acetylcholine

Chemical transmitter substance released by some nerve endings.

Action Potential

A large transient depolarization event, including polarity reversal, that is conducted along the membrane of a muscle cell or a nerve fiber.

Graded Response

A response that varies directly with the strength of the stimulus

Fused Tetanus

A smooth, sustained muscle contraction resulting from high frequency stimulation

Muscle Twitch

The response of a muscle to a single brief threshold stimulus.

Unfused Tetanus

Summed effects of muscle twitches prior to smooth sustained contraction.