ENDOCRINE GLANDS – 2
Follicular endocrine gland
The secretory cells of this type of endocrine glands are organized to form the wall of microscopic spheres or follicles. Their cells are usually a simple epithelium whose secretion accumulates inside the follicle.
The secretion the thyroid is called colloid and contains the precursors of thyroid hormones.
The figure highlights three follicles: their walls, formed by secretory cells, are highlighted in blue. The shape of the epithelial cells varies depending on the secretory activity of each follicle: they can be squamous, cuboidal or columnar – in this image they are mostly cuboidal. The colloid accumulated inside the follicles is highlighted in pink.
Groups of other endocrine cells are present between the follicles.
