1. Chapter 45 45.3-45.4 Pgs. 984-993 Objective: I can summarize the function of many different endocrine glands and hormones and be able to explain how a hormone pathway changes if alter hormone. Lots of details, so don’t worry about the stuff that has been italicized…

3.  Hypothalamus has neurosecretory cells  Extend to Posterior Pituitary (back)  Secrete to Vessels  Anterior Pituitary (front)  Tropic Hormones: target = endocrine gland/cells  Which releases tropic hormones? (anterior or posterior)? Which are definitely tropic here?

4.  Secretes 2 (neuro)hormones: peptides  Antidiuretic Hormone (ADH)  Acts on Kidney Tubules by increasing water reabsorption  Decreases blood osmolarity  Oxytocin  Uterine muscles  Contract in delivery  Mammary Glands  Lactate: eject milk Are either of these tropic? NO

5.  4 Tropic Hormones, 2 Nontropic Hormones, and 1 that can do both (Growth Hormone)

6.  4 Tropic Hormones: affects other endocrine organs  Follicle-Stimulating Hormone (FSH)  Luteinizing Hormone (LH)  Both are gonadotropins: stimulate gonads (testes & ovaries) to make hormones  Thyroid Stimulating Hormone (TSH)  Stimulates Thyroid to make Hormones  Adrenocorticotropic Hormone (ACTH)  Stimulates Adrenal Cortex to…hmmm…?  Neuroendocrine pathway: Hypothalamus releases neurohormone (tropic) to anterior pituitary  releases tropic hormone to target endocrine gland (classic cooperation between N & E) Glycoproteins Peptide

7.  2 Nontropic Hormones (both peptide)  Prolactin (PRL) – many effects  Mammary gland, fat metabolism  Melanocyte-Stimulating Hormone (MSH)  Pigment cells, also brain– inhibit hunger  Example of the evolution of hormones: different function in diff. species  Growth Hormone (similar to PRL)  Has tropic and non-tropic effects:  Releases growth factors, raises blood glucose Gigantism vs. Dwarfism

8.  Thyroid Hormones (amines)  T 3 = Triiodothyronine (holds 3 iodine atoms)  T 4 = Thyroxine (holds 4 iodine atoms)  Iodine is necessary in diet to make these hormones (iodized salt!)  Non-Human: helps in metamorphosis of frog  Human: helps in embryonic development  Also helps maintain blood pressure, heart rate, muscle, cellular metabolism  Hyperthyroidism  higher metab.  Graves’ disease  Hypothyroidism  lower metab., weight gain  Cretinism

9.  Reminder: the release of T 3 and T 4 by the thyroid is regulated by the release of…  TSH from the anterior pituitary gland, which will release when…  Hypothalamus sends Thyroid Releasing Hormone (TRH)  Presence of T 3 and T 4 repress production of TSH & TRH  But, when low on iodine…  So much TSH  enlarged thyroid called Goiter

10.  Thyroid  Calcitonin Hormone  Lowers blood calcium (Ca 2+ ) level  Parathyroid  Parathyroid Hormone (PTH)  Increases blood calcium (Ca 2+ ) level  Changing Blood Calcium (Ca 2+ ) Levels  Deposit/Remove from bones, also…  Stimulate/Reduce uptake in kidneys  PTH  activate vitamin D (hormonal form)  Increases (Ca 2+ ) uptake in intestines Peptide

11.  Both hormones are operating under negative feedback  Both hormones are antagonistic to each other  Both hormones help maintain homeostasis

12.  Both Endocrine (ductless) and Exocrine  Exocrine = secretes through ducts  Digestive: bicarbonate, enzymes  Endocrine Cells clustered: Islets of Langerhans  Alpha Cells produce glucagon hormone  Beta Cells produce insulin hormone  Glucagon increases glucose levels  Liver to break down glycogen: hydrolysis  Insulin decreases glucose levels  Liver to make glycogen: dehydration syn.  Encourage other cells to uptake glucose Peptide

13.  Glucagon affects other tissues besides liver: muscle & fat  Insulin allows cells to absorb glucose  Without this, metabolize fat and die

14.  If glucose levels are too high in the blood,  Glucose will be urinated out (sweet pee)  Type I Diabetes  Autoimmune disorder  Destroys Beta Cells that produce insulin  Need injections of insulin to live  Type II Diabetes  Cells become resistant to insulin signal  Can be incurred through weight gain and lack of exercise (also hereditary)

15.  Divided into 2 sections: outer/inner  Adrenal Cortex & Adrenal Medulla  Adrenal Medulla  Short-term stress  Epinephrine  Norepinephrine (aka adrenaline)  Nervous signal  Fight or flight  MANY effects only Amines

16.  Responds to endocrine signal from… (remember?)  Anterior Pituitary  ACTH (negative feedback)  Produces Corticosteroids hormones (3 types)  Glucocorticoids (i.e. cortisol)  Regulate glucose metabolism  Breakdown muscle and other tissues  Suppress immune system  Mineralocorticoids (i.e. aldosterone)  Alter salt and water levels which can… increase blood pressure (Aldosterone  RAAS)  Sex Hormones…but less important than... Long-Term Effects Steroids Beginning of lecture?

17.  Both sexes produce all sex hormones in gonads, just in different proportions  Sex Hormones (all steroids)  Androgens (i.e. testosterone)  Develop Male Reproductive structures  “Anabolic steroids” = artificial  Estrogens (i.e. estradiol)  Develop Female Reproductive structures  Progestin (i.e. progesterone)  Preparing for pregnancy Gonads respond to hormones from...Anterior Pituitary: FSH LH Gonadotropins Beginning of lecture?

18.  Non-Humans: can be found near surface of head  light  Humans: found within brain, but connected to optic region to detect light  Hormone: melatonin (amine)  Involved with biological rhythms (clock)  Melatonin secreted at night  Light detected determines secretion  Amount of light indicates seasons  Connected with seasonal behaviors…

19.  What do you already know?  Place where T cells develop  Produces Hormone  Thymosins (peptide hormone)  Stimulates development of T cells  Is the Thymus a part of Endocrine System or Immune System?  Maybe both?  Usually see Thymus as more a part of Immune system, due to its huge role there…