Certain glands are lacking in ducts and are termed endocrine glands. The endocrine glands secrete specific chemical substance called hormones which have specific effects on the other tissue or organs of the body e.g., thyroid, parathyroid, pituitary etc.
The secretions of these glands are conveyed directly into the blood stream.
To facilitate this endocrine glands have numerous sinusoids forming an extensive network, surrounding the secretory cells, which are usually arranged in small groups, follicles or anatomizing cords of cells.
