Endocrine System Hormones. AP Biology

Transkript

1 Endocrine System Hormones

2 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

3 Regulation & Communication Animals rely on 2 systems for regulation endocrine system system of ductless glands secrete chemical signals directly into blood chemical travels to target tissue slow, long-lasting response nervous system system of neurons transmits electrical signal & release neurotransmitters to target tissue fast, short-lasting response

4 Regulation by chemical messengers Neurotransmitters released by neurons Hormones release by endocrine glands neurotransmitter endocrine gland axon hormone carried by blood receptor proteins receptor proteins target cell

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

6 How do hormones act on target cells Lipid-based hormones hydrophobic & lipid-soluble diffuse across membrane & enter cells bind to receptor proteins in cytoplasm & nucleus bind to DNA as transcription factors Protein-based hormones hydrophilic & not lipid soluble can t diffuse across membrane receptor proteins in cell membrane trigger secondary messenger pathway activate internal cellular response enzyme action, uptake or secretion of molecules

7 Action of lipid (steroid) hormones target cell cytoplasm S 2 receptor protein S 1 steroid hormone S protein carrier blood transcription factor S 4 DNA nucleus 3 mrna 5 protein plasma membrane ex: growth factors (hair, bone, muscle, gametes)

8 Action of protein hormones protein hormone 1 P signal signal-transduction pathway activates ion channel or enzyme plasma membrane receptor protein cytoplasm ATP activates enzyme activates enzyme 2 messenger transduction 2 secondary messenger system target cell produces an action 3 response

9 Signal Transduction pathway 1 protein hormone P receptor protein cytoplasm GTP G protein ATP 2 activates enzyme activates enzyme activates enzyme camp 3 4 secondary messenger system produces an action 5

10 Action of epinephrine (adrenalin) 1 epinephrine activates adenylyl cyclase receptor protein cytoplasm GTP activates G protein GDP camp 3 2 ATP activates protein kinase-a 4 activates phosphorylase kinase activates glycogen phosphorylase adrenal gland released to blood liver cell glycogen 5 glucose 6

11 Benefits of a 2 messenger system signal receptor protein 1 Activated adenylyl cyclase 2 amplification Not yet activated 4 amplification GTP 3 G protein amplification 6 5 amplification camp protein kinase Amplification! FAST response! 7 amplification product enzyme

12 Maintaining homeostasis hormone 1 gland lowers body condition high specific body condition low raises body condition gland hormone 2 Negative Feedback Model

13 Nervous System Control Controlling Body Temperature hypothalamus nerve signals Feedback high body temperature (37 C) sweat low dilates surface blood vessels hypothalamus constricts surface blood vessels shiver nerve signals

14 Endocrine System Control Regulation of Blood Sugar insulin islets of Langerhans beta islet cells Feedback pancreas body cells take up sugar from blood liver stores glycogen reduces appetite high blood sugar level (90mg/100ml) low liver triggers hunger liver releases glucose pancreas liver glucagon islets of Langerhans alpha islet cells

15 Endocrine System Control Blood Osmolarity osmoreceptors in hypothalamus pituitary ADH increased water reabsorption increase thirst Feedback adrenal gland nephron high increased water & salt reabsorption aldosterone blood osmolarity blood pressure angiotensin low nephron (JGA) renin nephron angiotensinogen JuxtaGlomerular Apparatus

16 Nervous & Endocrine systems linked Hypothalamus = master nerve 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 pituitary hypothalamus posterior anterior

17 tropic hormones hypothalamus (TSH) Thyroid gland Adrenal cortex thyroid-stimulating hormone adrenocorticotropic hormone (ACTH) growth hormone (GH) posterior pituitary anterior pituitary gonadotropic hormones: folliclestimulating hormone (FSH) & luteinizing hormone (LH) antidiuretic hormone (ADH) melanocyte-stimulating hormone (MSH) prolactin (PRL) oxytocin Kidney tubules Muscles of uterus Melanocyte in amphibian Bone and muscle Testis Ovary Mammary glands in mammals

18 Homology in hormones What does this tell you about these hormones? How could these hormones have different effects? mammals prolactin birds fish same gene family gene duplication? amphibians growth hormone milk production fat metabolism salt & water balance metamorphosis & maturation growth & development

19 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

20 Goiter Iodine deficiency causes thyroid to enlarge as it tries to produce thyroxine

21 Endocrine System Control Regulation of Blood Calcium thyroid calcitonin kidney reabsorption of Ca ++ Feedback Ca ++ deposited in bones Ca ++ uptake in intestines high activated Vitamin D bones release Ca ++ blood calcium level (10 mg/100ml) kidney reabsorption of Ca ++ low parathyroid parathyroid hormone (PTH)

22 Female reproductive cycle Feedback ovary estrogen egg matures & is released (ovulation) builds up uterus lining corpus luteum FSH & LH pituitary gland GnRH no progesterone maintains uterus lining pregnancy fertilized egg (zygote) yes hcg corpus luteum progesterone hypothalamus corpus luteum breaks down progesterone drops menstruation maintains uterus lining

23 Effects of stress on a body Stress adrenal medulla secretes epinephrine & norepinephrine MEDULLA Nerve Spinal cord signals (cross section) (A) SHORT-TERM STRESS RESPONSE Nerve cell Nerve cell Adrenal gland Kidney Effects of epinephrine and norepinephrine: 1. Glycogen broken down to glucose; increased blood glucose 2. Increased blood pressure 3. Increased breathing rate 4. Increased metabolic rate 5. Change in blood flow patterns, leading to increased alertness & decreased digestive & kidney activity Releasing hormone ACTH Hypothalamus Anterior pituitary Blood vessel (B) LONG-TERM STRESS RESPONSE Effects of mineralocorticoids: 1. Retention of sodium ions & water by kidneys 2. Increased blood volume & blood pressure Effects of glucocorticoids: Adrenal cortex secretes mineralocorticoids & glucocorticoids 1. Proteins & fats broken down & converted to glucose, leading to increased blood glucose 2. Immune system suppressed CORTEX

24 Any Questions?? Robert Wadlow ' 11"