Vert Phys Exam 3 Study Guide Anatomy You should know i e be able to label the following organs The parts and valves of the heart Figure 13 10 13 11 The conduction system of the heart Figure 13 20 The basic scheme of the lymphatic system Figure 13 37 Basic anatomy of the lungs and alveoli Figure 16 4 and 16 14 Chapter 11 Endocrinology General Properties of Endocrine Systems Know the different types of chemical secretion signaling between cells Secretion of hormones from endocrine glands into the circulation and the action of those hormones on target tissues which have receptors for specific hormones Broadcast signal to distant tissues as opposed to point to point communication by nerves Exocrine and Endocrine Cells that secrete chemicals are called glands Inter cellular Signaling secreted chemicals act via receptors on the target cells and response follows o o o o o o o Exocrine secretion outside the body e g sweat glands Endocrine secretion into the blood acting on distant tissues Paracrine secretion acting on nearby cells o Autocrine secretion acting on same cell Endocrine Cell synthesizes hormone o When stimulated endocrine cell secretes hormone into blood Target Cell has receptors for the hormone and responds contracts secretes etc Endocrine Outline Leptin Demonstration of endocrine system see Chapter 19 p 666 Types of hormones and hormone receptor systems Examples of hormone systems Hypothalamic Pituitary Axes Hypothalamic Piutitary Adrenal HPA Axis Stress Response Hypothalamc Pituitary Thyroid Axis and Thyroid hormones iodine metabolism Insulin Glucagon see also chapter 19 p 672 678 Feedback Regulation variable up o High levels of regulated variable cause hypothalamus to down regulate behavior physiology that drive the o Negative feedback loop balances positive input no setpoint o Feedback loops Hypothalamus feeding circuitry eating energy storage Adipocytes Leptin in bloodstream hypothalamus Hormone Types o Nuclear Receptor Hormones Steroids Thyroid Hormone and Retinoic acid o Polypeptide and Glycoprotein Hormones Second Messenger Coupled Hormones GPCR linked to cAMP GPCR linked to phospholipase C and Ca Tyrosine Kinase Receptors o Many hormones are converted from prohormones or prehormones e g proinsulin is a polypeptide cleaved to form the smaller peptide insulin e g testosterone is a steroid that is converted to DHT or estradiol in target tissue e g T4 is coverted to the active T3 thyroid hormone Know the general properties of nuclear receptor hormones and their receptors Nuclear Receptor Hormones Steroids Thyroid Hormone and Retinoic acid Steroids and lipophilic hormones Intracellular receptors o DNA binding and gene transcription o o o Lipophilic molecules that pass through membranes and skin made up of sterol ring structures steroids or long chain hydrocarbons thyroid hormone retinoic acid that easily cross lipid bilayers Usually bound in the blood to carrier proteins that have hydrophobic domain that help them circulate through the body o Coordinate peripheral physiological and central neural response Because they can pass through membranes they readily diffuse throughout body and brain to produce parallel physiological and behavioral responses Note only cells that express the right receptors will respond to each hormone o Release regulated by synthesis Not easily contained in vesicles Synthesized from lipid soluble store by enzymes so no gene for these hormones although there are genes for synthesizing enzymes and for their receptors E g steroids synthesized from droplets of cholesterol in adrenal gland ovaries testes etc o o Bind to cytoplasmic nuclear receptors Lipophilic hormones can diffuse across cell membrane and bind receptors on the inside of cells Receptors bind to DNA affecting gene transcription Receptors bind to specific sequences response elements in gene promoters Because the nuclear receptors bind to DNA their effects are necessarily genomic e g not directly on ion channels or second messengers i e they induce protein synthesis It can take hours or days before the effect of nuclear receptor hormones is seen Estrogen receptor in presence of estrogen binds to estrogen response element Know the general properties of peptide hormones and their receptors Polypeptide and Glycoprotein Hormones Second Messenger Coupled Hormones o G protein induced cAMP and Ca signaling GPCR linked to cAMP GPCR linked to phospholipase C and Ca o Tyrosine Kinase Receptors o o o Peptide synthesis and processing Surface receptors Second Messenger Coupled Hormones Small peptides 4 100 amino acids long often identical to neuropeptides used by neurons as neurotransmitters Coded for by genes processed in endoplasmic reticulum Golgi apparatus packaged in vesicles and secreted by endocytosis Many peptide hormones are converted from prohormones e g proinsulin is a polypeptide cleaved to form the smaller peptide insulin Hydrophilic molecules so soluble in blood circulate and act on plasma membrane receptors on the surface of the cell to induce second messenger signaling in the target cells 3 Common Hormone Receptor Signaling Pathways GPCR linked to cAMP GPCR linked to phospholipase C and Ca Tyrosine Kinase Receptors o cAMP as a Second Messenger Hormone binds to receptor on target cell s plasma membrane Hormone receptor interaction acts by G proteins to stimulate adenylate cyclase on the cytoplasmic side of the membrane Activated adenylate cyclase catalyzes conversion of ATP to cyclic AMP cAMP in the cytoplasm Cyclic AMP activates protein kinase enzymes in the cytoplasm Activated cAMP dependent protein kinase phosphorylates transfers phosphate groups to activate inhibit other enzymes in the cell Enzyme activity mediates the target cell s response to the hormone gets the message across the membrane to inside of the cell amplifies the message by production of many cAMP molecules spreads the message by diffusion of cAMP throughout the cell o Intracellular Ca as a Second Messenger Hormone binds to receptor on target cell s plasma membrane Hormone receptor interaction acts by G proteins to stimulate phospholipase C enzyme in the membrane Activated phospholipase C catalyzes the conversion of phospholipds in the membrane to inositol triphosphate IP3 and diacylglycerol DAG IP2 enters teh cytoplasm and diffuses to the endoplasmic reticulum binds to IP3 receptors and causes Ca channels to open Endoplasmic reticulum has high Ca Ca rushes out of endoplasmic reticulum unto cytoplasm Ca in the
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