MEDULLARY SUBSTANCE Meaning and
Definition
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Medullary substance refers to the innermost part or core of an organ or structure within the body. It is commonly associated with the central nervous system, specifically in the brain and spinal cord. In these contexts, the medullary substance is further divided into two main regions: the medulla oblongata and the medulla spinalis.
The medulla oblongata is located at the base of the brainstem and serves as a connection between the spinal cord and the brain. It plays a vital role in controlling various involuntary functions, such as breathing, heart rate, blood pressure, and swallowing. The medulla oblongata also contains important nuclei responsible for regulating sleep, arousal, and maintaining balance.
On the other hand, the medulla spinalis, also known as the spinal cord, is a long, tubular structure running through the vertebral column. It serves as the primary pathway for conducting nerve signals between the brain and the rest of the body. The medullary substance of the spinal cord consists of both gray matter and white matter. The gray matter contains neuronal cell bodies and is involved in processing and integrating sensory information, while the white matter consists of myelinated nerve fibers that transmit signals to and from the brain.
In summary, medullary substance refers to the core or innermost part of an organ or structure, specifically within the brain and spinal cord, which plays a crucial role in controlling and transmitting important nerve signals throughout the body.
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(1) Myelin substance, white substance of Schwann; a soft material, composed of a network of neurokeratin enclosing in its meshes the semifluid myelin, which surrounds the axis-cylinder of a medullated nerve-fiber, and is itself surrounded by a delicate membrane, the neurilemma; it is interrupted at more or less regular intervals by constrictions of the neurilemma forming the nodes of Ranvier, the portion between two nodes being called an internode; (2) substantia medullaris.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
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The interior white portion of the brain.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
Common Misspellings for MEDULLARY SUBSTANCE
- medullary substancu
- medullary substancm
- medullary substanca
- medullary substancg
- m edullary substance
- me dullary substance
- med ullary substance
- medu llary substance
- medul lary substance
- medull ary substance
- medulla ry substance
- medullar y substance
- medullary s ubstance
- medullary su bstance
- medullary sub stance
- medullary subs tance
- medullary subst ance
- medullary substa nce
- medullary substan ce
- medullary substanc e
Etymology of MEDULLARY SUBSTANCE
The word "medullary" comes from the Latin word "medulla", which means "marrow". It is derived from the Proto-Indo-European root *medhu- which means "honey" or "fat". In ancient times, "medulla" was often used to refer to bone marrow, as it was thought to have a honey-like consistency. The term "substance" is derived from the Latin word "substantia" which means "upholding" or "supporting". So, when combined, "medullary substance" refers to the supportive tissue or matter, particularly in the context of the central nervous system, where it encompasses the white matter of the brain and spinal cord.
