1. u Chapter 45 ~ Chemical Signals in Animals

2. Regulatory systems u Hormone~ chemical signal secreted into body fluids (blood) communicating regulatory messages 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. Local regulators: cells adjacent to or near point of secretion u Growth factors ~ proteins for cell proliferation u Nitric oxide (NO) ~ neurotransmitter; cell destruction; vessel dilation u Prostaglandins ~ modified fatty acids secreted by placenta and immune system; also found in semen

4. Mode of Action: Chemical Signaling u 1- Plasma membrane reception signal-transduction pathways (neurotransmitters, growth factors, most hormones) u 2- Cell nucleus reception steroid hormones, thyroid hormones, some local regulators

5. Figure 45.3 Mechanisms of chemical signaling: a review

6. 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)

7. The hypothalamus & pituitary, I u Releasing and inhibiting hormones 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

8. Figure 45.6b Hormones of the hypothalamus and pituitary glands

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

10. Figure 45.6a Hormones of the hypothalamus and pituitary glands

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

12. Figure 45.9 Hormonal control of calcium homeostasis in mammals

13. 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)

14. Figure 45.10 Glucose homeostasis maintained by insulin and glucagon

15. The adrenal glands u Adrenal medulla (catecholamines): –epinephrine & norepinephrine~ increase basal metabolic rate (blood glucose and pressure) u Adrenal cortex (corticosteroids): –glucocorticoids (cortisol)~ raise blood glucose –mineralocorticoids (aldosterone)~ reabsorption of Na+ and K+ that increases blood pressure and volume. –Thought that these are what maintains body homeostasis over an extended period of time.

16. Figure 45.14 Stress and the adrenal gland

17. The gonads u Steroid hormones: precursor is cholesterol u Androgens –(testosterone)~ sperm formation; male secondary sex characteristics; gonadotropin u Estrogens –(estradiol)~ uterine lining growth; female secondary sex characteristics; gonadotropin u Progestins –(progesterone)~ uterine lining growth

18. Steroid Hormone Action u D:\ImageLibrary40- 55\45- ChemicalSignalsInAni mals\45-03a- NonsteroidHormone. mov D:\ImageLibrary40- 55\45- ChemicalSignalsInAni mals\45-03a- NonsteroidHormone. mov D:\ImageLibrary40 -55\45- ChemicalSignalsIn Animals\45-03b- SteroidHormone.m ov