Anatomy calls organs that synthesize and distinguish special substances – secrets.
The human body has a large number of different glands, many of which have microscopic sizes. They are located on the walls of the respiratory, digestive and genitourinary systems. Producing special mucus, the glands protect the walls of the cavities. Generations in the epithelium of the gastrointestinal tract produce enzymes that are responsible for digestion of food. Glands that are in human skin are called sweat and sebaceous glands. They help to remove harmful substances from the body.
Sometimes the body requires a large amount of secret. In this case, such glands as female mammary gland, pancreas, tear, salivary and other glands are responsible for its production.
All glands consist of cells – working and support cells. Work cells distinguish various substances, and support cells form the frame of the gland. Nerves and blood vessels pass through the frame.
Glands are exocrine and endocrine. Exocrine glands remove the secret they produce. These include tearful and salivary glands, also glands that are part of the skin, liver, etc. The endocrine includes those glands, the secret of which when isolated enters the bloodstream. These include the adrenal and thyroid glands, the pituitary gland. There are also glands of mixed secretion, they are the pancreas and sex glands.