medulla
Meaning
The innermost region of an organ or tissue, especially when it is distinct from the outer part.
The soft, inner part of a hair or feather.
The lower part of the brainstem, controlling automatic functions like breathing and heart rate.
Structure
Usage
The medulla oblongata is a vital part of the brain responsible for regulating involuntary functions.
A cross-section of the kidney reveals the darker outer cortex and the lighter inner medulla.
Damage to the adrenal medulla can disrupt the body's response to stress.
Etymology
The word "medulla" is a direct borrowing from Latin, where medulla specifically referred to the marrow inside bones or the pith inside a plant stem—the soft, essential core. This Latin term is thought to be a diminutive form, related to medius ("middle"), emphasizing the concept of being the innermost or central substance. Over time, its anatomical application in English expanded metaphorically from this literal core to designate the central, often softer, regions of various organs and structures, such as the brainstem (medulla oblongata), kidneys, and hair. Thus, the term consistently carries the fundamental logic of denoting an essential, internal core.
Analysis
- medull: From Latin medulla, meaning "marrow, pith, innermost part." - a: A common Latin noun ending, often used to form feminine nouns from stems.