matter (redirected from Heterogeneous matter)

matter /mat·ter/ (mat´er)

1. substance; anything that occupies space.

2. pus.

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gray matter  substantia grisea.

white matter  substantia alba.

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mat·ter (mtr)

n.

1. Something that occupies space and can be perceived by one or more senses.

2. A specific type of substance.

3. Discharge or waste, such as pus or feces, from a living organism.

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matter

Etymology: L, materia

1 anything that has mass and occupies space.

2 any substance not otherwise identified as to its constituents, such as gray matter, pus, or serum exuding from a wound.

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matter [mat´er]

1. physical material having form and weight under ordinary conditions; called also substance.

2. pus.

gray matter areas of the nervous system where the nerve fibers are unmyelinated (not enveloped by a myelin sheath); it contains the bodies of the nerve cells. Tissue composed of myelinated fibers is called white matter. The cerebral cortex is entirely composed of gray matter and the cerebellum also contains some deep-seated masses of it. The spinal cord has a central core of gray matter surrounded by white matter; in cross section, its gray matter is shaped approximately like the letter H. Called also substantia grisea and gray substance.

white matter areas of the nervous system composed mostly of myelinated nerve fibers (those having myelin sheaths) constituting the conducting portion of the brain and spinal cord. Tissue composed of unmyelinated fibers is called gray matter. Called also substantia alba and white substance.

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matter

1. physical material having form and weight under ordinary conditions of gravity.

2. pus.

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gray matter

matter of the central nervous system, which represents the aggregations of the nerve cells.

white matter

matter of the central nervous system, which comprises the axons of the nerve cells.

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matter

Anatomy Stuff that occupies cavities. See Gray matter, White matter.