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?

Ch. 45 Warm-Up Compare peptide hormones to steroids. Explain how insulin and glucagon work to regulate blood sugar levels. Which glands and hormones respond when your body is under stress?

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

You must know: Two ways hormones affect target organs. The secretion, target, action, and regulation of at least 3 hormones. An illustration of both positive and negative feedback in the regulation of homeostasis by hormones.

Hormones Why are hormones needed? chemical messages from one body part to cells in other parts of body communication needed to coordinate whole body maintaining homeostasis energy production growth development maturation reproduction growth hormones

Endocrine System Endocrine system releases hormones glands which secrete chemical signals into blood chemicals cause changes in other parts of body slow, long-lasting response growth hormones sex hormones response hormones metabolism hormones and more…. Hormones coordinate slower but longer–acting responses to stimuli such as stress, dehydration, and low blood glucose levels. Hormones also regulate long–term developmental processes by informing different parts of the body how fast to grow or when to develop the characteristics that distinguish male from female or juvenile from adult. Hormone–secreting organs, called endocrine glands, are referred to as ductless glands because they secrete their chemical messengers directly into extracellular fluid. From there, the chemicals diffuse into the circulation.

Types of Intercellular Signaling

Endocrine System = Hormone-secreting cells + Tissues Endocrine 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

Pheromones Hormones Local Regulators Chemical 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)

Glands Pineal Pituitary Thyroid Adrenal Pancreas Ovary Testes melatonin Pituitary many hormones: master gland Thyroid thyroxine Adrenal adrenaline Pancreas insulin, glucagon Ovary estrogen Testes testosterone

Discovery Video: Endocrine System

Types of Hormones Peptide Steroid Water-soluble Bind 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

Maintaining homeostasis hormone 1 gland lowers body condition high specific body condition low raises body condition gland hormone 2

specific body condition Negative Feedback Response to changed body condition every time body is high or low from normal level a signal tells the body to make changes that will bring body back to normal level once body is back to normal level, signal is turned off hormone 1 gland lowers body condition high specific body condition

Controlling Body Temperature Nervous System Control Controlling Body Temperature nerve signals brain sweat dilates surface blood vessels high body temperature low constricts surface blood vessels shiver brain nerve signals

Regulation of Blood Sugar Endocrine System Control Regulation of Blood Sugar insulin body cells take up sugar from blood liver stores sugar reduces appetite pancreas liver high blood sugar level (90mg/100ml) low liver releases sugar triggers hunger pancreas liver glucagon

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

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

Master Glands Hypothalamus Pituitary Gland

Master Glands Hypothalamus Pituitary Gland Receives 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

BIOFLIX: HOMEOSTASIS – BLOOD SUGAR

Control of Blood Glucose High 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

Diabetes Mellitus Type I diabetes (10%):deficiency of insulin Insulin-dependent Autoimmune disorder  beta cells of pancreas destroyed Type II diabetes (90%): failure of target cells to respond to insulin Non-insulin dependent Insulin produced  cells don’t respond (defect in insulin receptor or response pathway) Risk factors: obesity, lack of exercise