Control and Coordination

Pituitary gland has the following features:

• It is a pea shaped gland that is located below the hypothalamus in the brain.
• It is under the control of the hypothalamus and in turn controls many functions in the body.
• It is made up of three lobes - anterior, middle and posterior. They secrete hormones in response to the secretion of neurohormones by the hypothalamus.

Hormones Produced by Pituitary

Anterior Lobe

Anterior lobe of the pituitary produces six hormones:

• Thyroid stimulating hormone (TSH) which stimulates thyroid gland to produce thyroxine.
• Growth Hormone (GH) stimulates overall growth of the body. Its deficiency causes dwarfism and over-production causes gigantism.
• Adrenocorticotrophic hormone (ACTH) stimulates the adrenal cortex to produce corticosteroids that defend the body.
• Follicle stimulating hormone (FSH) stimulates testes to produce sperms and ovary to produce hormone oestrogen and ova (eggs).
• Luteinizing hormone (LH) stimulates testes to produce male hormone testosterone and in female, stimulates corpus luteum production which forms progesterone, a female hormone.
• Prolactin maintains the pregnancy and stimulates the secretion of milk.

Posterior Lobe

Posterior lobe secretes two hormones:

• Vasopressin or antidiuretic hormone (ADH) helps in maintaining blood pressure and preventing the kidneys from excreting very dilute urine. Lack of this hormone causes diabetes insipidus where glucose in urine does not show because the urine is very dilute.
• Oxytocin helps in contraction of uterus during delivery.