Cancer - organs that produce and emit specific substances of importance for the activity of those or other body systems. Some glands are Autonomous bodies, others are part of some authorities. Most glands develops from epithelium.
There are cancer with external secretion - exocrine (see the Sweat glands, Salivary glands and other), allocating the secret to the surface of the skin or in the body cavity (the gastrointestinal tract), and glands with internal secretion of endocrine allocating the secret is in the blood or lymph (see the Pituitary gland, Pancreas, Thyroid gland , and other). By type of secretion (see) gland is divided into merocrine (form a secret without violation of cytoplasm secretory cells), apocrine (form a secret with partial destruction of cytoplasm) and Holocene (secretion is accompanied by destruction of secretory cells).
Glands are unicellular (for example, goblet cells of the intestinal mucosa and respiratory) and multicellular. Multicellular glands can be simple or complex, branched and unbranched, alveolar, tubular and alveolar-tube (Fig.). In these glands are distinguished secretory, or limit, the Department and excretory duct. If excretory duct no forks, the gland is called simple; iron with branching flow (if every branch opens but several of the limit departments) are regarded as complex.
The secret glands can be protein, slimy, mixed, greasy. So gland is divided also on the protein (serous), mucous membranes, mixed and greasy.Structure multicellular exocrine glands
The structure of multicellular exocrine glands: 1 - simple unbranched tubular iron; 2 - simple unbranched alveolar iron; 3 - simple tubular iron branched limit Department; 4 - simple alveolar iron branched limit Department; 5 - complex alveolar-tubular iron.