Chapter 11 Endocrine System Sept 2020 PDF

Chapter 11 The Endocrine System Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 1 Nervous System vs. Endocrine System  Nervous System  Responsible for communication  Response to stimuli is near instantaneous...

Chapter 11 The Endocrine System Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 1 Nervous System vs. Endocrine System  Nervous System  Responsible for communication  Response to stimuli is near instantaneous  Electrical action potentials (electrical impulses) are sent via neurons to target cells using chemical messengers called neurotransmitters  Maintains homeostasis Nervous Systems. (2018, March 05). Retrieved from http://bio1520.biology.gatech.edu/chemical-and- electrical-signals/nervous-systems/ Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 2 Endocrine System (Fig. 11-1, p. 232)  Endocrine System  Responsible for communication  slower, longer-lasting type of control is provided  Endocrine glands synthesize & secrete chemicals (hormones) into intercellular fluid and then blood to travel distance to their target cells on target organs  Maintains homeostasis Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 3  Endocrine System  Hormones are main regulators of body processes including metabolism, growth & development, reproduction, inflammation, immunity  Hormones maintain homeostasis through fluid & electrolyte balance, acid-base balance, and energy balance  Hormones influence disease development i.e., Dwarfism, Gigantism, and sterility  Hormones are secreted by ductless endocrine glands into intercellular spaces/interstitial fluid and from there diffuse directly into blood vessels  Hormones bind to target cells on target organs that have specific receptors for the hormone – lock-and- key model of chemical activity Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 4  Second Messenger Mechanism  Nonsteroid hormones (protein/peptide hormones)  First messengers providing communication between gland & target organ or cell  Bind to receptors on the target cell membrane, activating second messengers to affect cell’s activities i.e., increase or decrease expression of specific genes including transcription, translation, & protein synthesis (Fig. 11- 2) Wan. (2014, July 29). PULSE Lecture 1. Retrieved from  e.g. TSH, glucagon, insulin, https://www.slideserve.com/wan/pulse-lecture-1 epinephrine, prolactin Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 5 https://www.youtube.com/watch?v=Nt2r5R0ZO5U Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 6  Steroid Hormone Action  Steroid hormones (lipid soluble - cholesterol)  Primary effects produced by binding to receptors within target cell nucleus & influence cell activity by acting on DNA—a slower process than nonsteroid action (Fig. 11-3)  Secondary effects may occur when steroid hormones bind to membrane receptors to rapidly trigger functional Steroid hormones action, eps10. (n.d.). Retrieved from https://www.gograph.com/clipart/steroid-hormones-action- changes in the target cell eps10-gg62484457.html Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 7 Steroid Hormone Action (Fig. 11-3, p. 234) Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 8 https://www.youtube.com/watch?v=m9jOXiYdMeY Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 9  Regulation Of Hormone Secretion  Hormone levels in blood are controlled by homeostatic mechanisms called negative feedback that reverse the direction of a change in a physiological system i.e. blood sugar levels (Fig. 11-4)  Positive feedback mechanisms (uncommon) that amplify/encourage physiological changes i.e. muscle contractions during labour, breast milk production (oxytocin) Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 10 NEGATIVE FEEDBACK (Fig. 11-4, p.235) Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 11  Prostaglandins (PGs)  Tissue hormones made of lipids also important in communication and control of body functions  Often produced & secreted in a tissue and then diffuse short distance to act on cells in that same tissue  Referred to as “paracrine agents” – released next to target cells rather than travelling distance to affect control  Effect on respiration, blood pressure, GI secretions, inflammation, & reproductive system  PGs may influence production cAMP Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 12 Hypothalamus and Pituitary Hormones (Fig. 11-5, p. 238) Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 13  Hypothalamus  Area of brain that links nervous system to endocrine systems via pituitary gland  Actual production of ADH and oxytocin occurs in the hypothalamus; after production in secretory neurons of hypothalamus, hormones pass along axons into the posterior pituitary gland  The secretion and release of posterior pituitary hormones is controlled by nervous stimulation  The anterior pituitary gland releases its hormones with help of hypothalamic releasing (RHs) and inhibiting hormones (IHs) delivered via blood vessels (bind to receptors on specific anterior pituitary cells causing release of hormone)  The hypothalamus controls many body functions related to homeostasis (temperature, appetite, & thirst) Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 14  Pituitary Gland (Fig. 11-5, p. 238)  No larger than pea; really 2 glands; anterior pituitary gland (adenohypophysis) and posterior pituitary gland (neurohypophysis)  Adenohypophysis has the epithelial structure of an endocrine gland; neurohypophysis has cellular structure of nervous tissue  Anterior pituitary gland  Names of major hormones Thyroid-stimulating hormone (TSH) Adrenocorticotropic hormone (ACTH) Follicle-stimulating hormone (FSH) Luteinizing hormone (LH) Growth hormone (GH) Prolactin (PRL) (lactogenic hormone) Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 15  Pituitary Gland (Cont’d)  Anterior pituitary gland (cont.)  Functions of major hormones TSH—stimulates growth of the thyroid gland; also stimulates it to secrete thyroid hormone ACTH—stimulates growth of the adrenal cortex & stimulates it to secrete glucocorticoids (mainly cortisol) FSH—initiates growth of ovarian follicles each month in the ovary and stimulates one or more follicles to develop to the stage of maturity and ovulation; stimulates estrogen secretion by developing follicles; stimulates sperm production in the male LH—acts with FSH to stimulate estrogen secretion and follicle growth to maturity; causes ovulation; causes luteinization of the ruptured follicle and stimulates progesterone secretion by corpus luteum; causes interstitial cells in the testes to secrete testosterone in the male GH—stimulates growth by accelerating protein anabolism; also accelerates fat catabolism & slows glucose catabolism; by slowing glucose catabolism, tends to increase blood glucose to higher than normal level (hyperglycemia) PRL, or lactogenic hormone—stimulates breast development during Slide 16 pregnancyMosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. & secretion of milk after the delivery of the baby  Pituitary Gland (Cont’d)  Posterior pituitary gland (neurohypophysis)  Names of hormones Antidiuretic hormone (ADH) Oxytocin  Functions of hormones ADH—major regulator of fluid balance; accelerates water reabsorption from urine in the kidney tubules into the blood, thereby decreasing urine secretion – prevents dehydration Oxytocin (OT)—stimulates the pregnant uterus to contract; may initiate labor; causes glandular cells of the breast to release milk into ducts; enhances social bonding between mother & infant Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 17  Thyroid Gland (Fig. 11-6, p. 239)  Names of hormones  Thyroid hormones—thyroxine (T4) and triiodothyronine (T3); produced with iodine from food  Calcitonin (CT)  Functions of hormones  Thyroid hormones—affect all body cells by accelerating catabolism (increase the body’s metabolic rate/speed up release of energy from nutrients)  CT—decreases the blood calcium concentration by inhibiting breakdown of bone, which would release calcium into the blood (helps prevent Marinelli, M. (2016, December 10). Thyroid and Parathyroid Surgery. Retrieved from hypercalcemia) https://basicmedicalkey.com/thyroid-and-parathyroid- surgery/ Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 18 Thyroid Gland Tissue Thyroid gland slide: Thyroid Gland Histology - Thyroid (labels) - histology slide -: Histology slides, Thyroid gland, Thyroid. (n.d.). Retrieved from https://www.pinterest.ca/pin/149885493822876952/ Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 19  Parathyroid Glands  Name of hormone— parathyroid hormone (PTH)  Function of hormone— increases blood calcium concentration by increasing the breakdown of bone with the release of calcium into the blood (opposite of calcitonin)  Also operates on kidneys & intestine to increase blood calcium  Too much blood calcium results in malfunction brain & heart cells; too little calcium Your Parathyroid glands-how one or more of these can become a problem. (2019, January 29). causes nerve cells become Retrieved from https://stopthethyroidmadness.com/parathyroid/ overactive & muscles go into spasm Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 20 Regulation Blood Calcium (Fig. 11-8, p. 241) Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 21  Adrenal Gland (Fig. 11-9, p.242) Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 22  Adrenal Glands  The Adrenal gland is two separate endocrine glands (like pituitary gland) – adrenal cortex & adrenal medulla  Adrenal cortex is outer layer made up glandular epithelium stimulated by ACTH of anterior pituitary  Adrenal medulla is inner layer made up of secretory nervous tissue stimulated by the sympathetic nervous system  Both work together in response to stress  Adrenal cortex  Three cell layers (zones) & corticoid hormones Outer layer secretes mineralocorticoids (MCs) e.g. aldosterone Middle layer secretes glucocorticoids (GCs) e.g. cortisol (hydrocortisone) Inner layer secretes sex hormones e.g. small amounts of male hormones (androgens) for both sexes – development reproductive organs; in women sex drive Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 23  Adrenal Glands (cont’d)  Adrenal cortex (cont’d)  Function of mineralocorticoids (Aldosterone) Increase blood sodium and decrease body potassium concentrations by accelerating kidney tubule reabsorption of sodium and excretion of potassium; affects of this hormone speed up reabsorption of water  Functions of glucocorticoids (Cortisol) Secretion of glucocorticoid quickly increases when the body is thrown into a condition of stress Help maintain normal blood glucose concentration by increasing gluconeogenesis—formation of “new” glucose from amino acids by breakdown of proteins, mainly those in muscle tissue cells; also conversion fatty acids to glucose by breakdown of fats stored in adipose tissue cells Play an essential part in maintaining normal blood pressure— make it possible for epinephrine and norepinephrine to maintain normal degree of vasoconstriction, a condition necessary for maintaining normal blood pressure Act with epinephrine and norepinephrine to produce an antiinflammatory effect, to bring about normal recovery from inflammations of various kinds Produce anti-immunity, antiallergy effect; bring about a decrease in number of lymphocytes & plasma cells & therefore a decrease in the amount ofitems Mosby antibodies and derived items ©formed 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 24 Adrenal Glands (cont’d)  Adrenal medulla  Names of hormones—epinephrine (Epi), or adrenaline, & norepinephrine (NR)  Functions of hormones—help the body resist stress by intensifying & prolonging the effects of sympathetic stimulation including heart rate, blood pressure, blood glucose levels; increased epinephrine secretion is the first endocrine response to stress  “Fight or Flight” response Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 25  Pancreatic Islets  Names of hormones of pancreatic islets (islets of Langerhans)  Glucagon—secreted by alpha cells  Insulin—secreted by beta cells  Functions of hormones  Glucagon increases the blood glucose level by accelerating liver glycogenolysis (conversion of glycogen to glucose)  Insulin decreases the blood glucose by accelerating the movement of glucose out of the blood into cells, which increases glucose metabolism by cells Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 26 Pancreas (Fig. 11-11, p. 251) Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 27  Female Sex Glands  The ovaries contain two structures that secrete hormones—the ovarian follicles & the corpus luteum; see Chapter 21 for more information  Ovarian follicles (pocket where egg cell develops) secrete estrogen  Corpus luteum (temporary structure of ovulation) secretes mainly progesterone (operates in conception and pregnancy) but some estrogen  Effects of estrogen (feminizing hormone) from these structures Development & maturation of breasts & external genitals Development of adult female body contours Initiation of menstrual cycle Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 28  Male Sex Glands  The interstitial cells of testes secrete the male hormone testosterone directly into blood; see Chapter 21  Effects of testosterone (masculinizing hormone)  Maturation of external genitals  Beard growth  Voice changes at puberty  Development of musculature and body contours typical of the male Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 29  Thymus  Thymus located in mediastinum; where many of the body’s cells of immunity develop  Name of hormone—thymosin (grp several hormones)  Function of hormone— regulates the development & function of T-cells – bodies immunity agents that defend against infection & cancer Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 30  Placenta  Temporary endocrine gland  Name of hormones—chorionic gonadotropins, estrogens, & progesterone  Function of hormones—maintain the corpus luteum during pregnancy Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 31  Pineal Gland  A small gland near the roof of the third ventricle of the brain  Glandular tissue predominates in children & young adults  Becomes fibrous & calcified with age  Called third eye because its influence on secretory activity is related to the amount of light entering the eyes  Secretes melatonin, which:  Inhibits ovarian activity & thus regulates puberty in women  Regulates the body’s internal clock – levels increase at night; decrease during the day Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 32 Other Endocrine Structures  Many organs (e.g., intestines, heart) produce endocrine hormones  Stomach lining produces ghrelin, which affects appetite & metabolism – secreted when stomach empty  The atrial wall of the heart secretes atrial natriuretic hormone (ANH), which stimulates sodium loss from the kidneys  Fat-storing cells secrete leptin, which controls how full or hungry one feels – fat stores empty signifies hunger Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 33  Other Endocrine Tissue & Hormones  Ghrelin – secreted by epithelial cells lining stomach that boosts appetite, slows metabolism, & reduces fat burning; secreted when stomach empty; involved development obesity  Atrial Natriuretic Hormone (ANH) – secreted by cells in wall of heart’s atria that regulates fluid & electrolyte balance & is antagonist to aldosterone; stimulates loss of sodium & water  Leptin – secreted by fat-storing cells throughout body that regulates hunger & how fat metabolized; may help to treat obesity, diabetes Mosby items and derived items © 2012 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 34