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Introductory Questions #8 1)Name the nine major endocrine glands found in the body. Which one is called the master gland? 2)Name three major local regulators.

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Presentation on theme: "Introductory Questions #8 1)Name the nine major endocrine glands found in the body. Which one is called the master gland? 2)Name three major local regulators."— Presentation transcript:

1 Introductory Questions #8 1)Name the nine major endocrine glands found in the body. Which one is called the master gland? 2)Name three major local regulators that act on nearby target cells. (pgs ) 3)Name three key molecules that play a role in the signal transduction pathway (typical reactions in the endocrine system). 4)How is the anterior part of the pituitary gland different from the posterior part? Name the hormones secreted from each area. Which region secretes fewer types of hormones? 5)Using the table on pg. 949, name the hormone(s) that: -Raises blood-calcium levels -maintains metabolic processes

2 Homeostasis & Osmoregulation Chapter

3 It assists the kidneys by –making urea from ammonia –breaking down toxic chemicals The liver is vital in homeostasis

4 Homeostasis: regulation of internal environment Thermoregulation internal temperature Osmoregulation solute and water balance Excretion nitrogen containing waste

5 Regulation of body temperature Thermoregulation 4 physical processes: Conduction~transfer of heat between molecules of body and environment Convection~transfer of heat as water/air move across body surface Radiation~transfer of heat produced by organisms Evaporation~loss of heat from liquid to gas Sources of body heat: Ectothermic: determined by environment Endothermic: high metabolic rate generates high body heat

6 Bears dont technically hibernate –They do enter a dormant state, when their body temperature drops by several degrees Bears are endotherms –Endothermic animals derive most of their body heat from metabolism –Ectothermic animals warm themselves mainly by absorbing heat from their surroundings Let Sleeping Bears Lie

7 Dormant bears have internal homeostatic mechanisms that compensate for fluctuations in the external environment –Thermoregulation maintains the body temperature within a tolerable range –Osmoregulation controls the gain and loss of water and dissolved solutes –Excretion is the disposal of metabolic wastes

8 Body temperature regulation requires adjustment to heat gained from or lost to an animals environment Heat is gained or lost in four ways Figure 25.1 ConvectionRadiation Evaporation Conduction

9 Hormonal changes may increase heat production by raising the metabolic rate –Fur and feathers help the body retain heat –Shivering, as these honeybees are doing, also increases metabolic heat production Figure 25.2A

10 Regulation during environmental extremes Torpor~ low activity; decrease in metabolic rate 1- Hibernation long term or winter torpor (winter cold and food scarcity); bears, squirrels 2- Estivation short term or summer torpor (high temperatures and water scarcity); fish, amphibians, reptiles Both often triggered by length of daylight

11 AP Biology Chapter 45. Endocrine System Hormones

12 AP Biology Regulation Why are hormones needed? chemical messages from one body part to another communication needed to coordinate whole body homeostasis & regulation metabolism growth development maturation reproduction growth hormones

13 AP Biology Regulation & Communication Animals rely on 2 systems for regulation endocrine system ductless gland which secrete chemical signals directly into blood chemical travels to target tissue slow, long-lasting response nervous system system of neurons, central nerve system transmits electrical signal to target tissue fast, short-lasting response

14 AP Biology Regulation by chemical messengers Axon Neurotransmitter Endocrine gland Receptor proteins Hormone carried by blood Target cell Neurotransmitters released by neurons Hormones release by endocrine glands

15 AP Biology Classes of Hormones Protein-based hormones polypeptides small proteins: insulin, ADH glycoproteins large proteins + carbohydrate: FSH, LH amines modified amino acids: epinephrine, melatonin Lipid-based hormones steroids modified cholesterol: sex hormones, aldosterone

16 AP Biology How do hormones act on target cells Lipid-based hormones lipid-soluble diffuse across membrane & enter cells bind to receptor proteins in cytoplasm & then this hormone-receptor complex moves into nucleus bind to receptor proteins in nucleus bind to DNA as transcription factors

17 AP Biology Nucleus Cytoplasm Steroid hormone (S) passes through plasma membrane. Inside target cell, the steroid hormone binds to a specific receptor protein in the cytoplasm or nucleus. Hormone-receptor complex enters nucleus & binds to DNA, causing gene transcription Protein is produced. Protein synthesis is induced. Plasma membrane DNA mRNA Protein Steroid hormone Blood plasma Protein carrier S S S 1 S Action of steroid (lipid) hormones

18 AP Biology How do hormones act on target cells Signal molecule Cell surface receptor enzyme G protein cAMP Target protein Nucleus Cytoplasm ATP Protein-based hormones hydrophilic & not lipid soluble cant diffuse across membrane trigger secondary (2°) messenger pathway transmit signal across membrane signal transduction usually activates a series of 2° messengers multi-step cascade activate cellular response enzyme action, uptake or secretion of molecules, etc.

19 AP Biology Action of protein hormones 3 4 GTP activates enzyme activates enzyme activates enzyme Receptor protein cAMP Protein hormone ATP 1 2 Cytoplasm Produces an action protein messenger cascade G protein

20 AP Biology adrenal gland Action of epinephrine (adrenalin) 3 4 GTP activates protein kinase-A activates phosphorylase activates adenylyl cyclase Receptor protein cAMP Epinephrine ATP 1 2 Cytoplasm G protein Liver cell Glucose Glycogen released to blood

21 AP Biology Benefits of a 2° messenger system Amplification! Signal molecule Receptor proteinActivated adenylyl cyclase Amplification GTPG protein Enzymatic product Enzyme Protein kinase cAMP Not yet activated

22 AP Biology Ductless glands release hormones into blood Tropic hormones= a hormone that has another endocrine gland as a target Endocrine system Duct glands = exocrine (tears, salivary)

23 AP Biology Major vertebrate hormones (1)

24 AP Biology Major vertebrate hormones (2)

25 AP Biology Endocrine & Nervous system links Hypothalamus = master control center nervous system receives information from nerves around body about internal conditions regulates release of hormones from pituitary Pituitary gland = master gland endocrine system secretes broad range of hormones regulating other glands

26 AP Biology Thyroid gland Hypothalamus Anterior pituitary Gonadotropic hormones: Follicle- stimulating hormone (FSH) & luteinizing hormone (LH) Mammary glands in mammals Muscles of uterus Kidney tubules Posterior pituitary Thyroid-stimulating Hormone (TSH) Antidiuretic hormone (ADH) Adrenal cortex Bone and muscle Testis Ovary Melanocyte in amphibian Adrenocorticotropic hormone (ACTH) Melanocyte-stimulating hormone (MSH) Oxytocin Prolactin (PRL) Growth hormone (GH)

27 AP Biology

28 AP Biology Homology in hormones prolactin mammalsbirdsamphibiansfish milk production fat metabolism metamorphosis & maturation salt & water balance growth hormone growth & development What does this tell you about these hormones? same gene family

29 AP Biology Hormones & Homeostasis Negative feedback stimulus triggers control mechanism that inhibits further change body temperature sugar metabolism Positive feedback stimulus triggers control mechanism that amplifies effect lactation labor contractions Anterior pituitary Inhibition – Target glands Hypothalamus Releasing hormones (TRH, CRH, GnRH) Tropic hormones (TSH, ACTH, FSH, LH) – (thyroid, adrenal cortex, gonads) Hormones

30 AP Biology Regulating blood sugar levels Islets of Langerhans Alpha cells: glucagon~ raises blood glucose levels Beta cells: insulin~ lowers blood glucose levels Type I diabetes mellitus (insulin-dependent; autoimmune disorder) Type II diabetes mellitus (non-insulin-dependent; reduced responsiveness in insulin targets)

31 AP Biology triggers release of glucose by liver - stimulates appetite Regulating blood sugar levels -triggers uptake of glucose by body cells -triggers storage in liver - depresses appetite pancreas beta islet cells alpha islet cells Islets of Langerhans Alpha cells: glucagon~ raises blood glucose levels Beta cells: insulin~ lowers blood glucose levels Type I diabetes mellitus (insulin- dependent; autoimmune disorder) Type II diabetes mellitus (non-insulin- dependent; reduced responsiveness in insulin targets)

32 AP Biology Regulating blood osmolarity If amount of dissolved material in blood is too high, need to dilute blood ADH Dehydration Lowers blood volume & pressure Increased water retention Increased vasoconstriction leading to higher blood pressure Reduced urine volume Osmotic concentration of blood increases ADH synthesized in hypothalamus ADH released from posterior pituitary into blood Osmoreceptors Negative feedback Negative feedback

33 AP Biology Regulating metabolism Hypothalamus TRH = TSH-releasing hormone Anterior Pituitary TSH = thyroid stimulating hormone Thyroid produces thyroxine hormones metabolism & development bone growth mental development metabolic use of energy blood pressure & heart rate muscle tone digestion reproduction tyrosine iodine thyroxine

34 AP Biology Goiter Iodine deficiency causes thyroid to enlarge as it tries to produce thyroxine

35 AP Biology Homology in hormones Days from emergence of forelimb TRH rises TRHTSHThyroxine –35–30–25–20–15–10– Thyroxine secretion rate Thyroxine stimulates metamorphosis in amphibians

36 AP Biology Regulating blood calcium levels Increased blood Ca ++ Thyroid Parathyroids Low blood Ca ++ Parathyroid hormone (PTH) Increased absorption of Ca ++ from intestine due to PTH activation of Vitamin D Reabsorption of Ca ++ & excretion of PO 4 Osteoclasts dissolve CaPO 4 crystals in bone, releasing Ca ++ – Negative feedback

37 The Gonads Steroid hormones : precursor is cholesterol –Androgens (testosterone) sperm formation male secondary sex characteristics; gonadotropin –Estrogens (estradiol) uterine lining growth female secondary sex characteristics gonadotropin –Progestins (progesterone) uterine lining growth

38 AP Biology Any Questions??

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