Unit 1 - Endocrine for Students PDF

HORMONE REGULATION Biology 1203 Unit 1 THE ENDOCRINE SYSTEM Laura Solteiro  Physiological controls of the body HOMEOSTASIS under stressful conditions This Photo by Unknown author is lice...

HORMONE REGULATION Biology 1203 Unit 1 THE ENDOCRINE SYSTEM Laura Solteiro  Physiological controls of the body HOMEOSTASIS under stressful conditions This Photo by Unknown author is licensed under CC BY-NC. RECALL FLUID COMPARTMENTS OF THE BODY 1. Intracellular Total body mass (female) Total body ▪ Cytosol within the cells mass (male) ▪ Fluid within each cell’s organelles 2. Extracellular 45% 40% ▪ Plasma (20%): liquid portion of blood Solids Solids ▪ Interstitial fluid (80%): between tissue Total body fluid cells, lymph, cerebrospinal fluid, synovial 2/3 fluid, eye fluid Intracellular fluid (ICF) Tissue cells 55% 60% Fluids Fluids Extracellular fluid 80% 1/3 Interstitial Extracellular fluid fluid (ECF) 20%Plasma Blood capillary  DEFINITIONS Internal environment = the extracellular compartment (in the body, outside of the cells) Homeostasis = The condition where the internal environment is relatively constant ▪ A dynamic state of the extracellular fluids ▪ Optimal concentration of gases, nutrients, ions, water ▪ Optimal temperature and pressure HOW DO HOMEOSTATIC MECHANISMS MAINTAIN BODY HEALTH? Used to maintain or restore homeostasis Involved in normal functioning of all body processes and for survival Usually done through negative feedback (see image) Example: If there is an increase in blood CO2 levels above homeostatic level: - The pons is stimulated and sends out order to increase breathing rate - Faster breathing expels CO2 from the blood - Blood CO2 levels drop to homeostatic levels HOMEOSTASIS: NEGATIVE FEEDBACK LOOP Sweat glands activated Stimulus: Heat Body temperature ↑ Stimulus: Cold Body temperature ↓ Shivering Marieb & Hoehn, 2018 Fig. 1.6 WHAT IS A GLAND? Gland = an organ that produces a secretion ▪ Secretion can be an enzyme, hormone, etc. ▪ Produced and secreted by specialized cells within the gland ▪ Secretion may be secreted onto a body surface (onto skin, into lumen of a digestive organ), or into body tissue (including blood) ▪ Can be endocrine or exocrine  GLAND Exocrine (Ducted) Glands Secretion Endocrine (Ductless) Glands is discharged onto the surface of an epithelium Secretion is discharged into the interstitial (e.g., skin) or body cavity (e.g., digestive tract) fluid and enters bloodstream Secretes products through a duct to a specific Do not have ducts target Products are distributed using blood or Duct can be short or long branched lymph Products: enzymes, ion Secretions are all hormones Examples: Examples: Sudoriferous glands (sweat) Pituitary gland Mammary glands (milk) Thyroid Salivary glands (digestive Adrenal glands enzymes) Pancreatic islets Sebaceous glands (oil) (glucagon and insulin) Pancreatic enzymes HORMONES Hormones = chemical messengers made by endocrine glands ▪ Long distance chemical signals; travel in blood or lymph ▪ released in one part of the body that regulates activity of another part of the body ▪ Each hormone has its own receptor in the target organs ▪ Different structures: ▪ Lipid hormones: steroids, thyroid hormones ▪ Amino acid hormones: amines (adrenaline), peptides (ADH), proteins (insulin, growth hormone)  BINDING OF HORMONES Water-Soluble Lipid-Soluble https://www.youtube.com/watch?v=DHa8JiqFg5Y https://www.youtube.com/watch?v=bEtZHeCPsBs 1 min lipid hormone binding to cell 1 min peptide hormone binding to cell STOP AND THINK Water-soluble hormones are ______ dissolved in the plasma of blood and bind to the ______ of their target cells. A. Easily ; receptor on the plasma membrane​ B. Easily ; cytoplasm and nucleus​ C. Not-Easily ; cytoplasm and nucleus​ D. Not-Easily ; receptor on the plasma membrane  FUNCTIONS OF HORMONES Function Example a) Stimulate exocrine glands to secrete Prolactin from pituitary gland stimulates milk secretion from mammary glands b) Stimulate other endocrine glands TSH from pituitary stimulates secretion of thyroid hormones c) Affect growth, development Growth hormone promotes body growth and and personality of an individual development d) Regulate body chemistry, metabolic Insulin from pancreas stimulates glycogenesis reactions e) Regulate muscle contraction and Epinephrine from adrenal gland increases heart nervous stimulation rate f) Control reproductive processes Estrogens from ovaries regulate menstrual cycle  ENDOCRINE AND NERVOUS SYSTEM ▪ Endocrine system acts with nervous system to coordinate and integrate activity of body cells Example) autonomic nervous system and epinephrine in an emergency situation ▪ Responses slower but longer lasting than nervous system responses ▪ Both directed by the hypothalamus I am the link! -hypothalamus ▪ Impulses from hypothalamus can lead to the secretion of hormones Hypothalamus Pituitary gland  NERVOUS SYSTEM VERSUS ENDOCRINE SYSTEM Nervous Endocrine Signalling mechanism(s) Electrical Chemical Chemical Primary chemical signal Neurotransmitters and action potentials Hormones released into blood Distance Short (neurotransmitters) Long or short (hormones) Response time Very fast Fast or slow Target(s) Specific (determined by axon pathways) Diffuse (anywhere blood reaches) Summary ▪ Nervous system: fast-acting, releases neurotransmitters ▪ Endocrine system: slower acting, long-lasting, releases hormones  Pineal gland Hypothalamus Pituitary gland ENDOCRINE GLANDS Thyroid gland Thymus Adrenal glands Parathyroid glands Pancreas Gonads Ovary (female) Testis (male) ENDOCRINE GLANDS (LABELLING PRACTICE)  HELPFUL HINTS - HORMONES Consider for each hormone: 1. What stimulates its production and/or release? 2. Where is it produced and/or released? 3. What organ(s) does it affect? 4. What is its' effect on the target organ(s)? 5. What is the overall effect (end result) of its release? HYPOTHALAMUS AND PITUITARY GLAND The hypothalamus is the major link between the nervous and endocrine systems – Located near the base of the brain, below thalamus – The pituitary hangs down from the hypothalamus on a stalk called the infundibulum Hypothalamus Infundibulum Anterior Pituitary Posterior Pituitary (Glandular tissue) (Neural tissue)  HYPOTHALAMUS AND PITUITARY GLAND A FUNCTIONAL RELATIONSHIP Components of the central nervous system Hypothalamus ▪ Targets pituitary gland ▪ Regulates blood osmotic pressure, glucose level, some hormone concentrations, body temperature Pituitary gland ▪ Directs other parts of the body ▪ Anterior and posterior lobes ▪ Hypothalamus works differently on anterior and posterior pituitary ▪ Different hormones released as a result  HYPOTHALAMUS AND Hypothalamic neurons synthesize releasing and inhibiting hormones ANTERIOR PITUITARY 1. When appropriately stimulated, hypothalamic neurons secrete releasing or inhibiting hormones into the primary capillary plexus 2. Hypothalamic hormones travel through portal veins A portal system is two to the anterior pituitary where they stimulate or capillary plexuses inhibit release of hormones made in the anterior (beds) connected by pituitary veins 3. In response to releasing hormones, the anterior pituitary secretes hormones into the secondary capillary plexus. This in turn empties into the general circulation Anterior Pituitary: Hypothalamic hormones released into special blood vessels (the hypophyseal portal system) control the release of anterior pituitary hormones ANTERIOR PITUITARY HORMONES The second capillary system of the hypophyseal portal system delivers the hypothalamic releasing hormones to the anterior pituitary, where six hormones (all peptides or proteins) are produced: 1. Growth hormone (GH) 2. Thyroid-stimulating hormone (TSH) 3. Adrenocorticotropic hormone (ACTH) 4. Follicle-stimulating hormone (FSH) 5. Luteinizing hormone (LH) 6. Prolactin (PRL)  ANTERIOR PITUITARY HORMONES Hormone Released From Anterior Hypothalamus Hormone Major Function/Target Pituitary Growth hormone-releasing hormone (GHRH) Growth Hormone Stimulates secretion of insulin-like growth factors (IGFs) that promote Growth hormone-inhibiting (GH) growth. Raise blood glucose levels hormone (somatostatin) also called somatotropin (liver and adipose) (GHIH) Thyrotropin releasing Thyroid Stimulating Hormone Stimulates synthesis and secretion of hormone (TSH) thyroid hormones by the thyroid gland (TRH) Stimulates release of Corticotropin releasing Adrenocorticotropic Hormone mineralocorticoid, glucocorticoid, and hormone (ACTHRH) (ACTH) androgen hormones from the adrenal cortex  ANTERIOR PITUITARY HORMONES Hormone Released From Hypothalamus Hormone Major Function/ Target Anterior Pituitary Ovaries initiate development of oocytes Follicle Stimulating hormone Testes initiate development of (FSH) spermatozoa Gonadotropic Releasing Hormone (GnRH) Luteinizing hormone Ovaries stimulate ovulation (LH) Testes stimulate testosterone production Prolactin Inhibiting Hormone PIH normally inhibits prolactin release (PIH) from anterior pituitary Prolactin Prolactin Releasing Hormone In nursing females: PRH stimulates (PRL) breast growth, development of the (PRH) mammary glands and milk production  THE HYPOTHALAMUS AND THE POSTERIOR PITUITARY ▪ The hypothalamus produces two hormones 1. Oxytocin 2. Antidiuretic Hormone (ADH) or Vasopressin ▪ The posterior pituitary stores and releases these hormones (but does not synthesize any hormones!) ▪ When stimulated, neurosecretory cells in the hypothalamus release oxytocin and ADH from their axon terminals located in the posterior pituitary  HYPOTHALAMUS AND POSTERIOR PITUITARY 1 1. Hypothalamic neurons synthesize oxytocin and Antidiuretic Hormone (ADH) 2. Oxytocin and ADH are transported down the axons of the hypothalamic-hypophyseal tract to the posterior pituitary 2 3. Oxytocin and ADH are stored in axon terminals in 3 the posterior pituitary 4. When associated hypothalamic neurons fire, action potentials arriving at the axon terminals cause 4 oxytocin or ADH to be released into the blood Posterior Pituitary: Action potentials travel down the axons of hypothalamic neurons, causing hormone release from their axon terminals in the posterior pituitary  OXYTOCIN ▪ Oxytocin targets smooth muscle in the uterus and breasts ▪ In the uterus, oxytocin stimulates uterine contractions, promoting labor and delivery ▪ After delivery, oxytocin stimulates “milk letdown” in the breasts in response to the suckling from an infant  ADH = ANTIDIURETIC HORMONE ▪ Antidiuretic Hormone (ADH) 3 targets: ▪ targets the collecting ducts in the kidney to retain water ▪ targets sweat glands in the skin to minimize water loss ▪ causes arterioles to constrict thereby increasing blood pressure  HYPOTHALAMUS AND PITUITARY GLAND ANTERIOR PITUITARY HORMONES FLAT PiG Follicle stimulating hormone Tropic Luteinizing hormone hormones Adrenocorticotropic hormone Thyroid stimulating hormone Prolactin Growth hormone HORMONES RELEASED POSTERIOR PITUITARY Oxytocin Antidiuretic hormone MAKE A HYPOTHALAMUS – PITUITARY FLOW CHART! STOP AND THINK The following hormones are synthesized in the posterior pituitary gland (neurohypophysis) A. ADH and oxytocin​ B. Oxytocin and insulin​ C. Insulin and ADH​ D. None of the above CHECKLIST OF GLANDS AND HORMONES 1. Hypothalamus: GnRH, ACTHRH, TSHRH, PRL, PIH, GHRH, not secreted: oxytocin, ADH 2. Anterior Pituitary : FSH, LH, ACTH, TSH, Prolactin, Growth hormone 3. Posterior Pituitary - not produced only secreted: ADH, oxytocin 4. Thyroid: thyroid hormone, calcitonin 5. Parathyroid: parathyroid hormone (PTH) 6. Adrenal cortex: cortisol, aldosterone, androgens 7. Adrenal medulla: adrenaline, noradrenaline 8. Pancreas: insulin, glucagon 9. Ovaries, testes: estrogen, testosterone 10. Pineal: melatonin 11. Thymus: thymosin 12. Stomach: gastrin 13. Small intestine: secretin, CCK Paracrine: prostaglandins THE THYROID GLAND ▪ The butterfly-shaped thyroid gland is located inferior to the larynx and anterior to the trachea ▪ It has two laterally placed lobes separated by a bridge-like isthmus HORMONES OF THE THYROID GLAND 1. Thyroid Hormone = T3 (triiodothyronine) + T4 (thyroxine) ▪ Stimulated by thyroid stimulating hormone (anterior pituitary) ▪ Major metabolic hormone of the body ❑ Raises body metabolism ❑ Increase breakdown of fats and carbohydrates ❑ Causes buildup and breakdown of some proteins ❑ Critical for development and maintenance of nervous system ❑ Regulates tissue growth and development, normal muscular development ❑ Affects heart rate, heartbeat and blood pressure ❑ Complex relationship with reproductive hormones Regulation of thyroid hormonesecretion. Hypothalamus ▪ TH release is regulated by ▪ negative feedback TRH ▪ Falling TH levels stimulate release of thyroid-stimulating hormone (TSH) ▪ Rising TH levels provide negative Anterior pituitary feedback inhibition on TSH ▪ TSH can also be inhibited by somatostatin (Growth Hormone Inhibiting Hormone), dopamine, and TSH increased levels of cortisol and iodide ▪ Hypothalamic thyrotropin-releasing Thyroid gland hormone (TRH) can overcome negative feedback during pregnancy or exposure to cold, especially in infants Thyroid hormones Stimulates Target cells Inhibits © 2017 Pearson Education, Inc.  DISORDERS OF THYROXINE SECRETION EITHER THE ANTERIOR PITUITARY OR THYROID GLAND IS AFFECTED → CHANGES LEVELS OF THYROID HORMONE Hypersecretion Grave’s disease Childhood ▪ same for children and adults ▪ goiter (enlarged thyroid) ▪ increased metabolic rate: high pulse rate, weight loss, irritability, nervousness, protruding eyes Adult ▪ controlled by surgery (remove thyroid) or drugs to suppress thyroid secretions GOITER AND LOW IODINE IN DIET ▪Goiter (enlarged thyroid gland) can be caused by high or low levels of thyroid hormone or by lack of iodine in diet ▪The thyroid gland enlarges in an attempt of trying to make more thyroid hormone  HORMONES OF THE THYROID GLAND 2. Calcitonin lowers the blood calcium level An increase in blood calcium will stimulate the thyroid to secrete calcitonin ▪ Inhibits osteoclast activity, inhibiting bone resorption and release of Ca2+ frombone ▪ Stimulates osteoblasts to uptake Ca2+ into bone ▪ Decrease calcium absorption in the intestines ▪ Increase calcium loss in urine STOP AND THINK Thyroid Stimulating Hormone (TSH) stimulates the release of A. Steroid hormones by the suprarenal glands​ B. Growth hormones by the hypothalamus​ C. Thyroid hormones by the thyroid gland​ D. Gonadotropins by the suprarenal glands THE PARATHYROID GLANDS ▪ The parathyroid glands are small, round masses of tissue attached to the posterior surface of the lateral Pharynx (posterior aspect) lobes of the thyroid gland ▪ Usually two per lobe Thyroid gland Parathyroid glands Esophagus Trachea PARATHYROID HORMONES Parathyroid hormone (PTH or parathormone) raises blood calcium levels Capillary ▪ Stimulates osteoclast activity so that Ca2+ is released from Parathyroid cells (secrete bone into the blood parathyroid hormone) ▪ Inhibits osteoblast activity ▪ Enhances reabsorption of Ca2+ by the kidneys Oxyphil cells ▪ Promotes activation of vitamin D by kidneys, increases absorption of Ca2+ from the GI tract  REGULATION OF BLOOD CALCIUM Low blood Ca2+ ▪ PTH release from parathyroid glands affects ▪ Bone ▪ Kidneys (recover calcium from filtrate) ▪ Intestine ▪ Kidney converts vitamin D to active form (calcitriol) ▪ Increases absorption Ca2+ in intestines High blood Ca2+ ▪ Calcitonin release from thyroid WHAT IF THERE IS TOO MUCH PARATHYROID HORMONE? Recall, Parathyroid Hormone normally increases blood calcium levels Hyperparathyroidism = too much parathyroid hormone ▪ High serum Calcium levels (lab) ▪ Bones broken down too much, become weak, deform and fracture easily WHAT IF THERE IS TOO LITTLE PARATHYROID HORMONE? Recall, Parathyroid Hormone normally increases blood calcium levels Hypoparathyroidism = too little parathyroid hormone ▪ Insufficient extracellular Ca2+ ▪ Unable to maintain resting state of neurons ▪ Neurons become depolarized in the absence of stimuli ▪ Leads to tetany (twitches, spasms, convulsions) THE PANCREAS ▪ The pancreas is both an endocrine and an exocrine gland ▪ It is located posterior and inferior to the stomach ▪ Most of the exocrine cells of the pancreas are arranged in clusters called acini and produce digestive enzymes which flow through ducts into the GI tract THE PANCREAS ▪ Distributed among the acini are clusters of endocrine tissue called pancreatic islets (islets of Langerhans) ▪ Each pancreatic islet contains four types of hormone-secreting cells HORMONES OF THE PANCREAS Alpha cells produce glucagon  Several targets  Main effect is to increase blood glucose levels Beta cells produce insulin  Several targets  Main effect is to decrease blood glucose levels (cells uptake glucose)  CARBOHYDRATE METABOLISM Glycogen Glycogenesis Glycogenolysis Glycolysis Gluconeogenesis Glucose ATP Amino acid Pyruvic Acid Lactic acid Glycerol Krebs ETC Cycle HORMONES OF THE PANCREAS ▪The hormonal control of blood glucose is complex, also involving epinephrine, growth hormone, and cortisol ▪ Insulin and glucagon are counter-regulatory hormones in that their actions act to balance one another in terms of blood glucose (antagonistic) GLUCOSE HOMEOSTASIS GLUCOSE HOMEOSTASIS WHEN THINGS GO WRONG Diabetes mellitus  Loss of insulin  No uptake of glucose (leads to hyperglycemia)  Leads to ketoacidosis Two types:  Type I: juvenile – beta cells are destroyed by immune system  Type 2: mature onset – cells do not respond to insulin; pancreas responds by making more insulin https://www.youtube.com/watch?v=MGMdKvZti1U Insulin binding to cell and glucose uptake 4 minutes  HORMONAL CONTROL OF BLOOD GLUCOSE Effect on Endocrine Hormone Action of Stimulated by… Blood Gland Secreted Hormone Glucose Pancreas High blood glucose Insulin ↑ glycogenesis ↑ gluconeogenesis Pancreas Low blood glucose Glucagon ↑ glycogenolysis Low blood glucose ↑ fat catabolism Anterior pituitary and Growth hormone ↓ glucose use GHRH Sympathetic Adrenal medulla Epinephrine ↑ glycogenolysis nervous system Adrenal cortex ACTH Glucocorticoids ↑ gluconeogenesis Thyroid gland TSH Thyroid hormone  THYROID GLAND AND BLOOD GLUCOSE RELATIONSHIP IS COMPLEX Hypothyroidism leads to hypoglycemia ▪ Decrease in glucagon secretion ▪ Gluconeogenesis and glycogenolysis impaired ▪ Slow glucose absorption in intestines Hyperthyroidism leads to hyperglycemia ▪ Increase in gluconeogenesis ▪ Increase in glucose absorption STOP AND THINK Which hormone is not involved in glucose metabolism? A. Cortisol B. Glucagon C. Insulin D. Epinephrine E. Aldosterone  THE ADRENAL GLANDS ▪ There are two adrenal glands, one superior to each kidney (also called the suprarenal glands). During embryonic development, the adrenal glands differentiate into two structurally and functionally distinct regions the adrenal cortex Steroid hormones like cortisol the adrenal medulla Catecholamines like norepinephrine THE ADRENAL GLANDS  THE ADRENAL CORTEX ▪ The adrenal cortex is peripherally located and makes up 80-90% of the total weight of the gland – The cortex is subdivided into three zones, each of which secretes a different group of steroid hormones, all formed from the cholesterol molecule 1. Mineralocorticoids 2. Glucocorticoids 3. Cortical sex hormones ADRENAL GLANDS ▪A cross-section shows that there are different sections and zones, each producing its own set of hormones CAPSULE ADRENAL CORTEX ADRENAL MEDULLA MINERALOCORTICOIDS: ALDOSTERONE ▪ Most superficial region synthesizes mineralocorticoid hormones essential for fluid and electrolyte balance ▪ Aldosterone is the major hormone in this group ▪ Function:  Regulate the concentrations of Na+ and K + in urine, sweat and saliva e.g.) Reabsorption of sodium, leading to increased water reabsorption (increased blood volume and pressure)  GLUCOCORTICOIDS: CORTISOL ▪ Middle zone mainly secretes glucocorticoid hormones (role in glucose metabolism) ▪ Cortisol is the major hormone in this group. Hypothalamus secretes CRH, triggers release of ACTH from anterior pituitary ▪ Function: ▪ Regulate metabolism by promoting the breakdown of proteins and fa ts to form glucose (gluconeogenesis). ▪ Increased blood sugar levels ▪ Assist the body to cope with stress CUSHING’S SYNDROME (LAB) ▪High levels of circulating cortisol, as seen with corticosteroid drugs (prednisone), or tumors (adrenal cortex, pituitary gland) is called Cushing's syndrome ▪Manifestations include ❑ hyperglycemia ❑ poor wound healing ❑ osteoporosis ❑ dermatitis ❑ moon face ❑ buffalo hump at the neck ❑ bruising ❑ truncal obesity ❑ fat redistribution (spindly arms and legs)  ADDISON’S DISEASE (LAB) ▪Only after his death did the world learn that President ▪ In adults, hyposecretion of glucocorticoids Kennedy suffered from Addison’s disease and aldosterone, usually as a result of an autoimmune disorder, is called Addison's disease ▪ The physiologic effects include ❑ Hypoglycemia ❑ Low BP ❑ Dehydration ❑ Muscle weakness ❑ Weight loss ❑ Na+ loss  TESTOSTERONE AND ESTROGEN ▪ Inner zone synthesizes androgens (male sex hormone testosterone) and estrogens (female sex hormones) ▪ Primary source until puberty ▪ Involved in the development of secondary sex characteristics in both sexes ▪ Males: testosterone further increases muscle development ▪ Females: may be source of estrogens postmenopause  ADRENAL MEDULLA HORMONES: EPINEPHRINE AND NOREPINEPHRINE ▪ The inner region of the adrenal gland is called the adrenal medulla and produces: epinephrine (adrenalin) and norepinephrine (noradrenalin). Both are also neurotransmitters that respond to fear, excitement and danger ▪ Effects of epinephrine and norepinephrine: ❑ Increase blood pressure (vasoconstriction) ❑ Increase rate and depth of breathing Epinephrine: ❑ Increased heart rate ❑ Increased blood glucose levels Norepinephrine: ❑ Blood diverted to brain, heart, and skeletal muscle, away from digestive system and skin STOP AND THINK Where are norepinephrine and epinephrine secreted from? A. Hypothalamus​ B. Adenohypophysis (anterior pituitary gland)​ C. The cortex of the suprarenal (adrenal) glands​ D. The medulla of the suprarenal (adrenal) glands WHAT IS STRESS? Stress = Any stimulus that leads to an imbalance to homeostasis Physical ▪ External: heat, cold, loud noise, lack of O2 ▪ Internal: pain, emotion, high blood pressure Psychological HOW DOES THE BODY DEAL WITH STRESS? General Adaptation Syndrome. Got GAS? 1. Alarm Phase 2. Resistance Phase 3. Exhaustion Phase 1. ALARM PHASE FIGHT OR FLIGHT RESPONSE ▪ Hypothalamus (autonomic nervous system) stimulates release of epinephrine and norepinephrine from adrenal medulla ▪ Body gets ready to respond! Marieb & Hoehn, 2018 2. RESISTANCE PHASE Helps the body fight the stress once the alarm phase is gone ▪ Hypothalamus stimulates anterior pituitary to produce hormones (e.g. ACTH) Glucocorticoids ▪ These hormones stimulate release of other hormones (e.g., from adrenal cortex) ↑ blood glucose Mineralocorticoids ↑ gluconeogenesis ↑ blood pressure Marieb & Hoehn, 2018 3. EXHAUSTION PHASE If resistance phase fails to combat the stressor and the body resources are depleted If this stage persists: health problems may occur ❑ Carbohydrate and fat stores depleted ❑ High blood pressure ❑ Muscle loss ❑ Suppression of immune system ❑ Ulceration of gastrointestinal tract ❑ Anxiety, depression STOP AND THINK The alarm phase of our response to stress produces all of the following except: A. increased heart rate and force of contraction B. dilation of vessels to the digestive organs C. increase in blood pressure D. decreased urinary activity E. increased glycogenolysis OVARIES: ESTROGENS AND PROGESTERONE ▪ Paired oval bodies in female pelvic cavity ▪ Stimulated by follicle-stimulating hormone (FSH) and luteinizing hormone (LH) ▪ Produces estrogens and progesterone ▪ Estrogens  development of primary (growth of uterus and vagina) and secondary (body hair, breasts, pelvis) sex characteristics OVARIES: ESTROGENS AND PROGESTERONE Progesterone ▪ Stimulates development of milk-secretory tissue in breasts ▪ Prepares uterine lining for implantation of fertilized ovum ▪ Helps maintain pregnancy ▪ Also produced by the corpus luteum and involved in ovulation and pregnancy TESTES: TESTOSTERONE ▪ Also stimulated by follicle-stimulating hormone (FSH) and luteinizing hormone (LH) ▪ The male gonads, the testes, are oval glands that lie in the scrotum ▪ Produces testosterone ▪ development of primary (penis and accessory glands) and secondary (body hair, voice changes) sex characteristics UNDERCOVER ENDOCRINE ORGANS Hormonal secretions are not their main job 1. Placenta (more during reproduction) 2. Stomach: gastrin to produce gastric juice (more during digestion) 3. Duodenum: secretin and cholecystokinin (more during digestion)  LESS UNDERSTOOD ENDOCRINE ORGANS 1. Thymus gland  Secretes thymosin – promotes development and maturation of T cells  Larger as a baby, decreases in size as age increases 2. Pineal gland  Secretes melatonin – acts on the hypothalamus to change levels of luteinizing hormone  Also responds to light and may be related to daily rhythms; more melatonin is secreted in darkness PROSTAGLANDINS ▪Hormones that act where they are produced, not in special organs or glands ▪Found in most body cells ▪Made of lipids in the plasma membrane ▪At least 15 discovered so far ▪Different types produced depending on the cell type producing them ▪Each prostaglandin has a different function (e.g., blood pressure, stomach secretions, immune responses, nerve impulses, control of uterine contraction etc.)