Muscle Terms

- Taylor's Anatomy & Physiology

Skeletal Muscle

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

Cardiac Muscle

Specialized muscle of the heart with striations & intercalated discs; involuntary muscle

Smooth Muscle

Muscle consisting of spindle-shaped, unstripped (non-striated) muscle cells; involuntary muscle

Perimysium

The connective tissue enveloping bundles of muscle fibers

Epimysium

The sheath of fibrous connective tissue surrounding a muscle

Tendon

Cord of dense fibrous tissue attaching a muscle to a bone

Myofibrils

Contractile organelles found in the cytoplasm of muscle cells

Sacromere

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

Myosin

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

Actin

One of the principal contractile proteins found in muscle; makes up thin filaments

Neurotransmitter

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

Action Potential

An electrical event occurring 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

Acetylcholine (ACh)

A chemical transmitter substance released by certain nerve endings

Lactic Acid

The product of anaerobic metabolism, especially in muscle

Origin

The muscle attachment that is not movable or is less movable than insertion

Insertion

The movable attachment of a muscle as opposed to its origin

Sacrolemma

Outer membrane covering of a skeletal muscle fiber

Tetanus

A serious disease of the nervous system caused by a toxin-producing bacterium (potentially deadly)

Aerobic

With oxygen

Anaerobic

Without oxygen

Prime Mover

The muscle most responsible for a joint action under load

Agonist

The muscle that is relaxing or lengthening

Synergist

Assist the agonist muscle or "primary mover" for a specific action at a joint

Fixators

A muscle that stabilizes or fixes a part of the body to which a muscle in the process of moving another part is attached

Motor Unit

A motor neuron and all of the muscle fibers it supplies