1 Ch. 40 Warm-Up What type of behavior in animals might be triggered by cold temperatures? What type of behaviors might be triggered in hot temperatures? List 2 examples of negative feedback. List 2 examples of positive feedback. What is the main type of chemical messenger in the endocrine system? The nervous system?

2 Ch. 45 Warm-Up Compare peptide hormones to steroids.Explain how insulin and glucagon work to regulate blood sugar levels.

3 Chapter 45 Hormones and the Endocrine SystemA hormone called ecdysteroid regulates the timing of metamorphosis in this anise swallowtail butterfly.

4 Types of Intercellular Signaling

5 Endocrine System = Hormone-secreting cells + TissuesEndocrine glands: ductless, secrete hormones directly into body fluids Hormones: chemical signals that cause a response in target cells (receptor proteins for specific hormones) Affects 1 tissue, a few, or most tissues in body Or affect other endocrine glands (tropic hormones) Regulation by Positive & Negative Feedback

6 Pheromones Hormones Local RegulatorsChemical signal from 1 individual to another individual Chemical signal from endocrine gland through blood to target cell Chemical signal from one cell to an adjacent cell Eg. ant trail; sex phermones Eg. peptide, steroid hormones Eg. cytokines, growth factors, nitric oxide (NO)

8 Discovery Video: Endocrine System

9 Types of Hormones Peptide Steroid Water-solubleBind to receptors on plasma membrane & triggers signal transduction pathway Affects protein activity already present in cell Rapid response Short-lived Eg. oxytocin, insulin, epinephrine Lipid-soluble Enters cell & binds to intracellular receptors Causes change in gene expression (protein synthesis) Slower response Longer life Eg. androgens (testosterone), estrogen, progesterone, cortisol

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11 Epinephrine: one hormone  many effectsLiver cells break down glycogen and release glucose Blood vessels to skeletal muscles dilate Blood vessels to intestines constrict

12 Master Glands Hypothalamus Pituitary Gland

13 Master Glands Hypothalamus Pituitary GlandReceives info from nerves and brain Initiates endocrine signals Hypothalamus Posterior pituitary gland: Oxytocin: contract uterine muscles, eject milk in nursing Antidiuretic Hormone (ADH): promote H2O retention by kidneys Pituitary Gland Anterior pituitary gland: Follicle-stimulating hormone (FSH): development of ovarian follicles (eggs); promote sperm production Luteinizing hormone (LH): trigger ovulation; stimulate testosterone production in testes

14 Hypothalamus regulation of Posterior Pituitary gland

15 Hypothalamus regulation of Anterior Pituitary gland

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18 Negative feedback systems:Thyroid hormones Blood Ca2+ levels Blood glucose levels Positive feedback system: Oxytocin (birthing process; release of milk/suckling)

19 BIOFLIX: HOMEOSTASIS – BLOOD SUGAR

20 Insulin & Glucagon: Control blood glucose levels

21 Control of Blood GlucoseHigh blood glucose Liver breaks down glycogen and releases glucose into blood Insulin released from pancreas Body cells take up glucose Liver stores glucose as glycogen Glucagon released from pancreas Blood glucose drops

23 Thyroid Gland Graves’ Disease: Autoimmune disorderHypothalamus TRH Anterior pituitary TSH Thyroid T3 T4 Graves’ Disease: Autoimmune disorder Antibodies bind to TSH receptor Hyperthyroidism High temp, sweating, weight loss, high BP

24 Stress and the Adrenal Gland