1. LectureDate _______ Chapter 45 Chemical Signals in Animals

2. Regulatory systems Hormone –chemical signal secreted into body fluids (blood) communicating regulatory messages Target cells –body cells that respond to hormones Endocrine system/glands~ –hormone secreting system/glands (ductless); exocrine glands secrete chemicals (sweat, mucus, enzymes) through ducts Neurosecretory cells –actual cells that secrete hormones Feedback mechanisms –negative and positive

3. Local regulators: cells adjacent to or near point of secretion Growth factors –proteins for cell proliferation Nitric oxide (NO) –neurotransmitter; cell destruction; vessel dilation Prostaglandins –modified fatty acids secreted by placenta and immune system; also found in semen

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

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

8. The hypothalamus & pituitary, I Releasing and inhibiting hormones Anterior pituitary: –Growth (GH)~bones gigantism/dwarfism acromegaly –Prolactin (PRL)~mammary glands; milk production –Follicle-stimulating (FSH) & –Luteinizing (LH) ~ ovaries/testes –Thyroid-stimulating (TSH) ~ thyroid –Adrenocorticotropic (ACTH) ~ adrenal cortex –Melanocyte-stimulating (MSH) –Endorphins~natural ‘opiates’; brain pain receptors

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

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

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

14. The adrenal glands Adrenal medulla (catecholamines): –epinephrine & norepinephrine - increase basal metabolic rate (blood glucose and pressure) Adrenal cortex (corticosteroids): –glucocorticoids (cortisol) - raise blood glucose –mineralocorticoids (aldosterone) - reabsorption of Na+ and K+

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