The initial thyroid precursor, the thyroid primordium, starts as a simple midline thickening and develops to form the thyroid diverticulum. This structure is initially hollow, although it later solidifies and becomes bilobed. The 2 lobes are located on either side of the midline and are connected via an isthmus. [ ]

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Term information

database cross reference


plural term
thyroid primordia [ ZFA:0001081 ]

external definition

Portion of tissue part of the pharyngeal endoderm that is fated to become thyroid follicle[ZFIN:curator].

external ontology notes

Note that we follow EHDAA2 in dividing this into endoderm and mesenchyme. In this ontology we place the broad developmental relationship at this level, and include specific relationships to the pharyngeal endoderm at the level of the endoderm

has related synonym

thyroid primordia



taxon notes

In all vertebrates the thyroid arises from the ventral aspect of the second pouch