ultimobranchial tissue

anatomy

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 17, 2026

Quick Summary

Ultimobranchial tissue refers to small bodies in the vertebrate embryo's pharynx that develop behind the gill pouches. In mammals, this tissue is integrated into the parafollicular cells of the thyroid gland. The primary function of ultimobranchial glands is the production of the hormone calcitonin. Calcitonin plays a crucial role in regulating calcium levels in the blood by reducing them when they rise above normal. This hormone acts on bone, decreasing the resorption of calcium from the skeleton into the bloodstream, thereby opposing the action of parathyroid hormone.12

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

hormone
Ultimobranchial tissue and calcitonin
Its actual source is the ultimobranchial tissue, represented in vertebrates from fishes upward by the ultimobranchial gland, which develops from the hinder part of the pharynx. Ultimobranchial tissue is the source of distinctive cells (called light, C, or parafollicular cells), which are found in the thyroid gland of mammals; in…
Read More
Its actual source is the ultimobranchial tissue, represented in vertebrates from fishes upward by the ultimobranchial gland, which develops from the hinder part of the pharynx. Ultimobranchial tissue is the source of distinctive cells (called light, C, or parafollicular cells), which are found in the thyroid gland of mammals; in…
Read More