medulla

views updated Jun 11 2018

me·dul·la / məˈdələ/ • n. Anat. the inner region of an organ or tissue, esp. when it is distinguishable from the outer region or cortex (as in a kidney, an adrenal gland, or hair). ∎ short for medulla oblongata. ∎ Bot. the soft internal tissue or pith of a plant.DERIVATIVES: med·ul·lar·y / məˈdələrē; ˈmejələrē/ adj.

The Oxford Pocket Dictionary of Current English

medulla oblongata

views updated Jun 11 2018

medulla oblongata Part of the vertebrate brainstem, derived from the hindbrain, that is continuous with the spinal cord. Its function is to regulate the reflex responses controlling respiration, heart beat, blood pressure, and other involuntary processes. It gives rise to many of the cranial nerves.

A Dictionary of Biology

medulla

views updated May 14 2018

medulla
1. The central part of a structure, e.g. the pith of a stem
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2. A tangle of loose fungal hyphae
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3. A layer of loose hyphae in the thallus of a lichen.

A Dictionary of Plant Sciences MICHAEL ALLABY

medulla

views updated May 17 2018

medulla (mi-dul-ă) n.
1. the inner region of any organ or tissue, particularly the inner part of the kidney, adrenal glands, or lymph nodes. m. oblongata (myelencephalon) the extension within the skull of the upper end of the spinal cord, containing centres responsible for the regulation of the heart and blood vessels, respiration, salivation, and swallowing.

2. the myelin layer of certain nerve fibres.
—medullary adj.

A Dictionary of Nursing

medulla oblongata

views updated May 23 2018

me·dul·la ob·long·a·ta / äˌblôngˈgätə/ • n. the continuation of the spinal cord within the skull, forming the lowest part of the brainstem and containing control centers for the heart and lungs.

The Oxford Pocket Dictionary of Current English

medulla

views updated May 18 2018

medulla
1. (in zoology) The central tissue of various organs, including the adrenal glands (adrenal medulla) and kidneys (renal medulla).

2. (in botany) See pith.

A Dictionary of Biology