 The endocrine system helps the body grow, develop and maintain homeostasis.  The endocrine system makes chemicals called hormones that act to maintain homeostasis.  Hormones are made by organs known as glands.

 As hormones move through the body they will be in contact with many cells, however they will only interact with specific cells that have the proper receptor.  Cells that have the correct receptors are called target cells.

 There are two categories of hormones: › Steroid hormones › Non-steroid hormones  ALL steroid hormones are made from cholesterol, which is a lipid.

 The hypothalamus acts as a connection between the CNS and the endocrine system.  The hypothalamus is located at the base of the brain.

 As part of the CNS the hypothalamus receives, interprets, and sorts information from the sensory organs.  As part of the endocrine system, the hypothalamus produces releasing hormones.

 The hypothalamus is known as the master control center of the endocrine system. › Its endocrine signals directly control the pituitary gland which secretes hormones that will influence body functions.

 Hypothalamus releases TRH in response to cold exposure, which stimulates the pituitary to release TSH.  TSH is called thyroid- stimulating hormone. Thyroid is stimulated to release thyroxine.  Thyroxine is released into the blood where it increases the metabolic rate of body cells, thereby warming the body.  Warmth of body ends stimulation of hypothalamus, halting the cycle. See how the hypothalamus controls EVERYTHING ?

 The pituitary gland is actually an extension of the hypothalamus, which consists of an anterior and posterior lobe.

 The thyroid gland helps to regulate development and metabolism.  The thyroid and parathyroid gland maintain calcium homeostasis by regulating the hormone calcitonin.

 The adrenal glands, which are located on top of the kidneys, produce hormones that enable the body to respond to stress.