Acinus is a medical term that refers to a small sac or acorn-shaped structure found in certain glands. The spelling of acinus can be tricky, as the pronunciation of the "c" and "u" sounds can vary. In IPA phonetic transcription, this word is spelled /əˈsaɪnəs/ with a schwa sound at the beginning, followed by a long "i" sound, then a short "i" sound, and ending with a "nus" sound. The correct spelling of acinus is important for accurate communication in the medical field.
An acinus (plural acini) refers to a small functional unit seen in different biological structures throughout the human body. The term is derived from the Latin word "acinus," which means "berry." Generally, an acinus refers to a small, rounded or oval-shaped structure found in a gland, organ, or tissue, often resembling a cluster of grapes.
In anatomy, acini are often observed in the respiratory system, particularly in the lungs, where they are part of the pulmonary lobule. They are involved in the oxygen exchange process, with each acinus primarily composed of alveoli, blood vessels, and connective tissue. Here, acini allow for efficient gas transfer between inhaled air and the bloodstream.
Additionally, acini are prominent in various exocrine glands, such as the salivary glands, pancreas, and lacrimal gland. These glands contain acini that produce and secrete substances such as saliva, digestive enzymes, and tears, respectively. The acini in these glands consist of secretory cells arranged in clusters, often with a central lumen or duct through which the secretions pass.
In histology, the term "acinus" can also refer to the smallest functional unit of certain organs, such as the liver or kidney, where it describes the structure surrounding a central blood vessel. This acinus-like arrangement aids in the organization and functioning of these organs, allowing for efficient processing and filtration of substances.
Alveolus. 1. One of the minute sac-like beginnings of the excretory ducts of an acinous or alveolar gland, an aggregation of which constitutes a lobule. 2. An air-cell of the lung. 3. A lobule of the liver.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "acinus" originates from the Latin word "acinus", which means "berry" or "grape". It is derived from the Proto-Indo-European root *h₂eh₁k- meaning "sharp" or "thorn-like", which is also the origin of other words like "acid" and "acorn". In anatomy, "acinus" specifically refers to small rounded structures resembling grapes that are found in various organs, such as the lung, liver, or prostate.