organ subunit

organ region with fixed fiat boundary

A part of an organ that constitutes a distinct modular sub-unit. In some cases, the organ may also contain other sub-units of identical or similar types, in other cases this may be a distinct entity.

Type Organ
Parent Structure organ part
Latin Name organ region with fixed fiat boundary
FMA ID 86140

Sub-structures

anterior segment of eyeball Organ bronchopulmonary segment Organ chamber of eyeball Organ cloacal bursa Organ costal diaphragm Bone crus of diaphragm Bone duct Organ glans Organ kidney calyx Organ lesser sac Organ metabolic zone of liver Organ ocular surface region Gland pilosebaceous unit Muscle posterior segment of eyeball Organ renal corpuscle Organ sac of scrotum Organ sallet Organ segmental subdivision of nervous system Bone skin appendage follicle Organ tooth crown Organ tooth root Bone vertebra lamina Bone

Frequently Asked Questions

What is an organ subunit and how does it relate to the whole organ?
An organ subunit is a distinct modular component that constitutes a functional and structural subdivision within an organ. Organ subunits may be repeated units — for example, the nephron in the kidney, the liver lobule in the liver, or the pulmonary lobule in the lung — where multiple identical subunits execute the organ's function in parallel. Alternatively, an organ may contain distinct, non-identical subunits like the cortex and medulla of the adrenal gland, each performing different functions.
What are examples of well-known organ subunits?
Key examples include: the nephron (functional subunit of the kidney, each containing glomerulus, tubules, and collecting duct — approximately one million per human kidney), the hepatic lobule (hexagonal subunit of the liver organized around a central vein), the pulmonary alveolus (gas-exchange subunit of the lung), the ovarian follicle (reproductive subunit of the ovary), and the seminiferous tubule (sperm-producing subunit of the testis). Each represents a modular repeating unit that collectively creates organ function.
Why is the concept of organ subunit important in medicine and physiology?
Understanding organ subunits is critical because many diseases operate at the subunit level. Glomerulonephritis damages nephrons selectively while leaving surrounding kidney tissue intact. Hepatic cirrhosis disrupts the lobular architecture of the liver. Pulmonary fibrosis damages alveolar subunits. Quantifying surviving functional subunits (e.g., nephron number, hepatocyte mass) is essential for assessing organ reserve and predicting disease trajectory.

Related Structures

1st arch mandibular component ventral mandibular arch 1st arch mandibular ectoderm ectoderm of mandibular component 1st arch mandibular mesenchyme mandibular component mesenchyme 1st arch mandibular mesenchyme from head mesenchyme 1st arch mandibular mesenchyme from neural crest 1st arch maxillary component 1st arch maxillary ectoderm ectoderm of maxillary component 1st arch maxillary-mandibular cleft 1st arch maxillary-mandibular groove ectoderm

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Educational Disclaimer

This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical decisions.

Data sources: Terminologia Anatomica, Foundational Model of Anatomy, Wikidata.