Chapter 45 Hormones and the Endocrine System Overview Metamorphosis controlled by hormones Hormones secreted into extracellular fluid/circulates in blood or hemolymph/communicates regulatory *messages *only target cells have receptors Overview(cont) Hormones regulate reproduction, growth, metabolism, behavior 45.1 Hormones and other signaling molecules bind to target receptors, triggering specific response pathways Types of Secreted Signaling Molecules 1. Hormones endocrine vs exocrine 2. Local Regulators paracrine vs autocrine signaling 3. Neurotransmitters and Neurohormones - synapse 4. Pheromones Intercellular Signaling Synaptic Signaling Neurohormones Pheromones Chemical Classes of Hormones 1. polypeptides 2. amines 3. steroid hormones Water soluble or lipid solubleent/chp42/4202s.swfent/chp42/4202s.swf Center for BioMolecular Modeling Action of Epinephrine on a Liver Cell Thyroid Hormone Animation Scientific Inquiry Location of receptors and their interaction with hormones??? Rats and estradiol(radioactive form) Frogs and melanocyte-stimulating hormone(MSH) Fig What if? Multiple Effects of Hormones Water-soluble hormone tissues vary in response due to different receptors or signal transduction pathways Fig p. 980 Lipid-soluble hormone different effect on different target cells Ex) estrogen - different effect in different species Ex) thyroxine Signaling by Local Regulators Cytokines Growth factors Nitric oxide Prostaglandins Nitric Oxide Aspirin and prostaglandins 45.2 Negative feedback and antagonistic hormone pairs A) Simple Hormone Pathways low pH in duodenum secretin pancreas bicarbonate reduction in stimulus B) Insulin and Glucagon an antagonistic pair see Fig p alpha and beta cells of pancreas Control of Blood Glucose Diabetes Mellitus Deficiency in insulin or a decreased response to insulin Type I autoimmune/insulin dependent/destroys beta cells Type II heredity and excess body weight/target cells are non-responsiverFiles/0%20- %20Sean/FastFacts%20March% pdfrFiles/0%20- %20Sean/FastFacts%20March% pdf