1. u Chapter 45 ~ Chemical Signals in Animals

2. Regulatory systems u Hormone~ chemical messengers secreted by endocrine gland into blood and transported to target cell u Target cells~ body cells that respond to hormones u Endocrine system/glands~ hormone secreting system/glands (ductless); exocrine glands secrete chemicals (sweat, mucus, enzymes) through ducts u Neurosecretory cells~ actual cells that secrete hormones u Feedback mechanisms ~ negative and positive

3. Mode of Action: Chemical Signaling u 1. protein hormones- bind to membrane receptors;involve secondary messenger u 2. steroid hormones- enter cell and interact with genes directly u 3. tyrosine derivative-increase metabolic rate

4. Vertebrate Endocrine System u Tropic hormones ~ a hormone that has another endocrine gland as a target u Hypothalamus~pituitary u Pituitary gland u Pineal gland u Thyroid gland u Parathyroid glands u Thymus u Adrenal glands u Pancreas u Gonads (ovary, testis)

5. The hypothalamus & pituitary, I u Hypothalamus is “boss” of pituitary u Anterior pituitary: u Growth (GH)~bones √gigantism/dwarfism √acromegaly u Prolactin (PRL)~mammary glands; milk production u Follicle-stimulating (FSH) & u Luteinizing (LH)~ovaries/testes u Thyroid-stimulating (TSH)~ thyroid u Adrenocorticotropic (ACTH)~ adrenal cortex u Melanocyte-stimulating (MSH) u Endorphins~natural ‘opiates’; brain pain receptors

6. The pituitary, II u The posterior pituitary: u Oxytocin ~ uterine and mammary gland cell contraction u Antidiuretic (ADH )~ retention of water by kidneys

7. The pineal, thyroid, & parathyroid u Melatonin ~ pineal gland; biological rhythms u Thyroid hormones: Calcitonin~ lowers blood calcium Thyroxine~ metabolic processes u Parathyroid (PTH)~ raises blood calcium

8. The pancreas u Islets of Langerhans u Alpha cells: glucagon~ raises blood glucose levels u Beta cells: insulin~ lowers blood glucose levels u Type I diabetes mellitus (insulin-dependent; autoimmune disorder) u Type II diabetes mellitus (non-insulin-dependent; reduced responsiveness in insulin targets)