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Endocrine System Hormones AP Biology 2007-2008 Regulation Why are hormones needed? chemical messages from one body part to another communication needed to coordinate whole body daily homeostasis & regulation of large scale changes solute levels in blood glucose, Ca++, salts, etc. metabolism growth development maturation AP Biology reproduction growth hormones Regulation & Communication Animals rely on 2 systems for regulation _______________________ system of ductless glands secrete chemical signals directly into blood chemical travels to target tissue target cells have receptor proteins slow, long-lasting response _______________________ system of neurons transmits “electrical” signal & release neurotransmitters to target tissue fast, short-lasting response AP Biology Regulation by chemical messengers _____________________ released by neurons _______________ release by endocrine glands endocrine gland neurotransmitter axon hormone carried by blood receptor proteins AP Biology receptor proteins target cell Classes of Hormones ___________________________ polypeptides small proteins: ________, _________ insulin glycoproteins large proteins + carbohydrate: ______, _______ amines modified amino acids: ___________, __________ ___________________________ steroids modified cholesterol: _____________, __________ AP Biology How do hormones act on target cells _______________________________ __________________ & lipid-soluble diffuse across cell membrane & enter cells bind to receptor proteins in cytoplasm & nucleus bind to DNA as ________________________ _______________________________ _______________________________ __________________ & not lipid soluble AP Biology can’t diffuse across cell membrane bind to receptor proteins in cell membrane trigger ________________________________ activate internal cellular response enzyme action, uptake or secretion of molecules… Action of lipid (steroid) hormones steroid hormone target cell S 1 S cross cell membrane S cytoplasm blood protein carrier 2 binds to receptor protein becomes transcription factor 5 S 3 mRNA read by ribosome plasma membrane DNA 4 mRNA nucleus 6 protein 7 protein secreted AP Biology ex: secreted protein = growth factor (hair, bone, muscle, gametes) signal-transduction pathway Action of protein hormones 1 protein hormone P signal plasma membrane binds to receptor protein activates G-protein activates enzyme cAM P receptor protein activates cytoplasmic signal GTP cytoplasm AP Biology target cell acts as 2° messenger transduction ATP ATP activates enzyme 2 secondary messenger system activates enzyme produces an action 3 response Ex: Action of epinephrine (adrenalin) adrenal gland signal 1 epinephrine activates G protein receptor protein in cell membrane activates GTP 3 activates adenylyl cyclase cAMP GDP transduction 4 GTP 2 ATP activates protein kinase-A 5 activates phosphorylase kinase cytoplasm liver cell AP Biology released to blood activates glycogen phosphorylase glycogen 6 glucose 7 response Benefits of a 2° messenger system1 signal Activated adenylyl cyclase receptor protein 2 Not yet activated amplification 4 3 GTP amplification cAMP amplification 5 G protein protein kinase 6 amplification Amplification! enzyme Cascade multiplier! AP Biology FAST response! 7 amplification product Maintaining homeostasis hormone 1 lowers body condition gland high specific body condition low raises body condition AP Biology gland hormone 2 Negative Feedback Model Nervous System Control Feedback Controlling Body Temperature nerve signals sweat high body temperature (37°C) low constricts surface shiver blood vessels AP Biology nerve signals dilates surface blood vessels Endocrine System Control Regulation of Blood Sugar insulin Feedback islets of Langerhans beta islet cells body cells take up sugar from blood liver stores glycogen high blood sugar level (90mg/100ml) low triggers hunger AP Biology liver releases glucose glucagon islets of Langerhans alpha islet cells reduces appetite Endocrine System Control Blood Osmolarity osmoreceptors in hypothalamus Feedback ADH increased water reabsorption increase thirst high blood osmolarity blood pressure low increased water & salt reabsorption JuxtaGlomerular Apparatus renin aldosterone AP Biology angiotensinogen angiotensin Nervous & Endocrine systems linked ________________ = “master control center” _______________________ receives information from nerves around body about internal conditions regulates release of hormones from pituitary ________________ = “master gland” _________________________ secretes broad range of hormones regulating other glands hypothalamus anterior pituitary AP Biology posterior tropic hormones = target endocrine glands Hypothalamus thyroid-stimulating hormone (TSH) Thyroid gland Adrenal cortex antidiuretic posterior hormone pituitary (ADH) anterior pituitary gonadotropic hormones: folliclestimulating hormone (FSH) & luteinizing hormone (LH) Kidney tubules Muscles of uterus Melanocyte in amphibian Bone and muscle AP Biology Testis Ovary Mammary glands in mammals Homology in hormones What does this tell you about these hormones? How could these hormones have different effects? same gene family gene duplication? prolactin mammals milk production AP Biology birds fat metabolism fish amphibians salt & water balance metamorphosis & maturation growth hormone growth & development Regulating metabolism Hypothalamus _____ = _______________________ Anterior Pituitary _____ = _______________________ Thyroid produces _____________________ metabolism & development AP Biology bone growth mental development metabolic use of energy blood pressure & heart rate muscle tone digestion reproduction tyrosine + iodine thyroxines Goiter Iodine deficiency causes thyroid to enlarge as it tries to produce thyroxine tyrosine + APiodine Biology thyroxines Endocrine System Control Feedback Regulation of Blood Calcium calcitonin kidney reabsorption of Ca++ thyroid Ca++ deposited in bones high blood calcium level Ca++ uptake in intestines (10 mg/100mL) low activated Vitamin D bones release Ca++ AP Biology kidney reabsorption of Ca++ parathyroid parathyroid hormone (PTH) Feedback Female reproductive cycle egg matures & is released (ovulation) estrogen builds up uterus lining corpus luteum ovary progesterone FSH & LH maintains uterus lining pituitary gland hCG yes pregnancy GnRH hypothalamus AP Biology fertilized egg (zygote) no corpus luteum breaks down progesterone drops menstruation corpus luteum progesterone maintains uterus lining AP Biology Any Questions?? Robert Wadlow 1918-1940 8' 11" AP Biology 2007-2008