The endocrine system regulates body functions through hormones. It includes glands that secrete hormones directly into the bloodstream, such as the pituitary gland. The pituitary gland controls many other glands and produces growth hormone and thyroid stimulating hormone. The thyroid gland produces thyroid hormones which control metabolism. Other glands include the pancreas, which produces insulin and glucagon to regulate blood sugar, and the adrenal glands, which produce cortisol and other hormones involved in stress response.

1. The Endocrine System Healthy Living thru Chemistry

3. 2 . Hormones are classified chemically into three types. a. amino acid based molecules - proteins, peptides, amines b. steroid molecules - made from cholesterol c. prostaglandins - made from lipid-like molecules B. Mechanism of hormonal actions 1. A given hormone only affects a specific tissue or organ - called the target cell, target tissue, target organ 2. Hormone (Greek word - to arouse) - hormones exert their effect by changing the normal activity of their target

4. 3 . Hormones exert their effect in one of 4 ways a. They may change the permeability or electrical potential of a cell membrane. b. They may cause the synthesis of proteins in the cell. c. They may activate or inactivate enzymes. d. They may stimulate mitosis

5. 4 . Hormones trigger changes in their target cells by two mechanisms. a. Steroidal hormones can pass through the cell membrane. 1. enter the cell 2. enter the nucleus 3. bind to receptor proteins 4. cause the synthesis of active proteins

6. b. Non-steroidal hormones cannot pass through the cell membrane 1. cannot enter the cell 2. enter the nucleus 3. this binding activates an enzyme 4. the enzyme catalyzes the reactions that produce the effect

9. b. humeral stimuli (humor = old term for body fluids) - changing levels of a chemical in the blood stimulate release of the hormone Ex - rising blood glucose levels stimulate the release of insulin c. neural stimuli - nerve fibers stimulate the release of hormones Ex. - activation of the sympathetic nervous system causes the release of epinephrine

23. 2. Glucocortoids have the following effects: - promote normal metabolism - resistance to stress - stimulates glucose production - reduces inflammation - reduces edema, reduces pain

24. 3. Sex Hormones - Androgens in males Estrogen in females The Adrenal Medulla produces 2 hormones 1. epinephrine 2. norepinephrine 3. They both mediate the fight or flight response – raise blood pressure increase respiration increase heart rate dilate the air ways increase blood glucose levels

25. E. Pancreatic Islet Cells – the Islets of Langerhans These cells produce 2 hormones Insulin is produced by the beta cells - released in response to increased glucose levels in the blood - increases a cells transport of glucose across the cell membrane - it lowers blood glucose levels

26. b. Glucagon is produced by the alpha cells. - released in response to lowered blood glucose levels - stimulates the liver to break down glycogen to form glucose - increases blood glucose levels

29. F. Pineal Gland – located in the brain The function of this gland is not well understood. The gland does produce Melatonin Melatonin levels vary with each 24 hour period of time. Melatonin may play a role in our bio rythyms. G. Thymus – present in the fetus and neonate. Not present in adults 1. The thymus produces a hormone that stimulates the maturation of lymphocytes