Ch. 32 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. 32 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 32 – Part II Endocrine System

What you must know: The endocrine system is one of two body systems for communication and regulation. How hormones are transported, bind to specific target cells, and trigger cellular responses. The secretion, target, action, and regulation of at least two hormones. An illustration of both positive and negative feedback in the regulation of homeostasis by hormones.

Types of Intercellular Signaling

Endocrine System = Hormone-secreting cells and 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 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)

Discovery Video: Endocrine System

Simple Endocrine Pathway

Simple Neuroendocrine Pathway

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

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, thyroid hormone

Peptide vs. Steroid Hormones

Fight or Flight Response Learn Genetics Video Clip (4:29 min) Fight or Flight Response

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

Hypothalamus regulation of Posterior Pituitary gland

Hypothalamus regulation of Anterior Pituitary gland

BIOFLIX: HOMEOSTASIS – BLOOD SUGAR

Insulin & Glucagon: Control blood glucose levels

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

REGULATION OF METABOLISM THYROID GLAND: REGULATION OF METABOLISM

Homeostatic Imbalance: Graves Disease Autoimmune disorder Antibodies bind to TSH receptor Hyperthyroidism (overproduce T3 and T4 hormones) Bypass TSH negative feedback loop High temp, sweating, weight loss, high BP

Homeostatic Imbalance: Hashimoto’s Thyroiditis Autoimmune disorder Antibodies destroy thyroid gland Low levels of thyroid hormone TSH levels rise Hypothyroidism Low temp, gain weight, sluggish, low heart rate

Stress and the Adrenal Gland