The pancreas is located behind the stomach in the region of the first and second lumbar vertebrae. The specialized cells in the pancreas that produce hormones are called the islets of Langerhans (islet cells of the pancreas).

The islets of Langerhans produce two hormones, insulin (produced by beta cells) and glucagon (produced by alpha cells). Both of these hormones play a role in the proper metabolism of sugars and starches in the body. Insulin is neccessary in the bloodstream so that sugars can pass from the blood into the cells of the body where they are burned to release energy. When blood sugar (glucose) is above normal level, insulin is released, which stimulates the conversion of glucose to glycogen (a starch-storage form of sugar) in the liver. Glucagon, the opposite "twin" of insulin, is released into the blood when sugar levels are below normal. It causes the breakdown of stored liver glycogen to glucose.

PITUITARY GLAND

The pituitary gland, also called the hypophysis, is a small, pea-sized gland located at the base of the brain in a small, pocket-like depression of the skull called the sella turcica. It is a well-protected gland with the entire mass of the brain above it and the nasal cavity below.

The pituitary consists of two distinct parts: an anterior lobe called the adenohypophysis, which is formed by an upgrowth from the pharynx and is glandular in nature; and a posterior lobe called the neurohypophysis, which is derived from a downgrowth from the base of the brain and is composed of nervous tissue. The hyothalamus is a region of the brain that is in close proximity to the pituitary gland. Signals transmitted from the hypothalamus control the secretions by the pituitary gland. Secretion from the neurohypophysis is controlled by the nerve fibers originating in the hypothalamus and ending in the neurohypophysis. Secretion by the adenohypophysis is controleld by special hormones called releasing and inhibiting factors.