|Description:||Organ: Thyroid, Species: Avian (Canadian goose). Comments: The thyroid
contains numerous follicles of various sizes. The colloid inside the
follicles contains thyroglobulin that is the storage form of thyroxine,
one of the two hormones produced by the thyroid. This gland is inactive
because the interfaces between the colloid and the epithelial cells are
smooth. Note the capillaries that form a network around the follicles.
Parafollicular cells that produce calcitonin are not seen here. They
are best demonstrated with immunohistochemistry.|