Endocrine System Part 2 PDF

e Endocrine Syste Pa 2 Presented by Assistant professor Dr. Ali Al-najjar General Surge...

e Endocrine Syste Pa 2 Presented by Assistant professor Dr. Ali Al-najjar General Surgeon e First & e Only Franchise in the Iraq  e Pineal Gland Pineal gland—attached to roof of third ventricle beneath the posterior end of corpus callosum After age 7, it undergoes involution (shrinkage) – Down 75% by end of pube y – Tiny mass of shrunken tissue in adults May synchronize physiological function with 24-hour circadian rhythms of daylight and darkness – Synthesizes melatonin from serotonin during the night Fluctuates seasonally with changes in day length e First & e Only Franchise in the Iraq Identify the Structure Corpus Callosum Fornix Cingulate Gyrus Central Sulcus Parieto- Occipital Sulcus Pineal Body Septum Pellucidum Anterior Commisure  e ymus Thymus plays a role in three systems: endocrine, lymphatic, immune Located in the mediastinum superior to the hea – Goes through involution after pube y Site of maturation of T cells impo ant in immune defense T lymphocytes Secretes hormones (thymopoietin, thymosin, and thymulin) that stimulate development of other lymphatic organs and activity of Copyright © e McGraw-Hill Companies, Inc. Permission required for reproduction or display. yroid Trachea ymus Lung Hea Diaphragm Liver (a) Newborn (b) Adult e First & e Only Franchise in the Iraq  Largest endocrine gland e yroid Gland – Composed of two lobes and an isthmus below the la nx – Dark reddish brown color due Copyright © e McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior thyroid a e and vein yroid ca ilage to rich blood supply Normally not palpable and not yroid visible If enlarged in size called Goiter gland Isthmus Inferior thyroid vein Trachea (a)  e yroid Gland Secretes thyroxine (T4 because of four Copyright © e McGraw-Hill Companies, Inc. Permission required for reproduction or display. iodine atoms) and triiodothyronine (T3)—T4 which is conve ed to T3 Superior thyroid yroid a e and vein ca ilage – Increases metabolic rate, O2 consumption, heat production yroid (calorigenic e ect), appetite, growth gland hormone secretion, ale ness, quicker Isthmus re exes Parafollicular (C or clear) cells secrete Inferior thyroid vein Trachea calcitonin with rising blood calcium – Stimulates osteoblast activity and bone formation (a) e First & e Only Franchise in the Iraq  e yroid gland:- (all true except one) a-Largest endocrine gland B-Two lobes and an isthmus below the la nx c-Secretes thyroxine (T4) and triiodothyronine (T3) d- yroid hormones decreases metabolic rate, O2 consumption, heat production appetite, e-Parafollicular cells secrete calcitonin e First & e Only Franchise in the Iraq 8  e Parathyroid Glands Usually four glands paially Pha nx posterior. embedded in posterior su ace wall of thyroid gland Secrete parathyroid hormone (PTH) yroid – Increases blood Ca2+ levels gland Promotes synthesis of calcitriol Increases absorption of Ca2+ Decreases urina excretion Parathyroid Increases bone resorption Esophagus Trachea e First & e Only Franchise in the Iraq Q- e parathyroid hormone (PTH):- a-Increases blood Ca2+ levels b-Promotes synthesis of calcitriol c-Increases absorption of Ca2+ d-Increases bone resorption e-All the above are true. e First & e Only Franchise in the Iraq 10 Q- e parathyroid hormone (PTH):- a-Increases blood Ca2+ levels b-Promotes synthesis of calcitriol c-Increases absorption of Ca2+ d-Increases bone resorption e-All the above are true. e First & e Only Franchise in the Iraq 11  Connective tissue capsule Zona glomerulosa Adrenal co ex Adrenal medulla Zona Adrenal fasciculata co ex (a) Zona e Adrenal Glands reticularis Small gland that sits on top of each kidney ey are retroperitoneal like the kidney Adrenal Adrenal co ex and medulla formed by medulla merger of two fetal glands with di& erent e First origins e Only Franchise in theand Iraq functions  e Adrenal Medulla Adrenal medulla—inner core, 10% to 20% of gland Acting as an endocrine gland and sympathetic ganglion of sympathetic ne ous system – Inne ated by sympathetic bers – When stimulated release catecholamines (epinephrine and norepinephrine) and a trace of dopamine directly into the bloodstream E ect is longer lasting than neurotransmitters – Increases ale ness and prepares body for physical activity – Increases blood pressure, hea rate, blood ow to muscles, pulmona ai low, and metabolic rate – Decreases digestion and urine production e First & e Only Franchise in the Iraq  e Adrenal Co ex Surrounds adrenal medulla and produces more than 25 steroid hormones called co icosteroids or co icoids Secretes ve major steroid hormones from three layers of glandular tissue – Zona glomerulosa (thin, outer layer) Secretes mineraloco icoid—regulate the body’s electrolyte balance, e.g:- Aldosterone stimulates Na+ retention and K+ excretion – Zona fasciculata (thick, middle layer) – Secretes glucoco icoids, Especially co isol, stimulates fat and protein catabolism, gluconeogenesis ,Anti-in ammato e ect becomes immune suppression with long-term use – Zona reticularis (narrow, inner layer) – Secretes sex steroids, Androgens: sets libido throughout life; Estradiol: small e First & equantity, Only Franchise in the Iraq  e Pancreatic Islets Exocrine digestive gland and endocrine cell clusters (pancreatic islets) found retroperitoneal, inferior and posterior to stomach Tail of pancreas Bile duct (c) Pancreatic islet Exocrine acinus Pancreatic Duodenum Head of ducts pancreas Beta cell (a) Alpha cell Delta cell (b) Pancreatic islet c: © Ed Reschke e First & e Only Franchise in the Iraq 17-15  e Pancreatic Islets Glucagon—secreted by A or alpha cells – Released between meals when blood glucose concentration is falling Insulin secreted by B or beta cells – Secreted during and after meal when glucose and amino acid blood levels are rising so lowering blood glucose levels – Insu ciency or inaction is cause of diabetes mellitus Somatostatin secreted by D or delta ( ) cells – Pa ially suppresses secretion of glucagon and insulin Gastrin secreted by G cells – Stimulates e First & stomach acid secretion, motility, and emptying e Only Franchise in the Iraq e First & e Only Franchise in the Iraq 17  stomch spleen pancrease duodenum e First & e Only Franchise in the Iraq  e Gonads Ovarian hormones,Estradiol, progesterone, and inhibin Functions of estradiol and progesterone – Development of female reproductive system and physique including adolescent bone growth – Regulate menstrual cycle, sustain pregnancy – Prepare mamma glands for lactation Inhibin suppresses FSH secretion from anterior pituita Testicular hormones,Testosterone, androgens, estrogen, inhibin – Testosterone Stimulates development of male reproductive system in fetus and adolescent, and sex drive Sustains sperm production – Inhibin Limits FSH secretion in order to regulate sperm e First & e Only Franchise in the Iraq Endocrine Functions of Other Tissues and Organs Skin:-Keratinocytes conve a cholesterol-like steroid into cholecalciferol using UV from sun Liver—calcidiol, angiotensinogen ,e thropoietin Hepcidin: promotes intestinal absorption of iron Kidneys—Conve calcidiol to calcitriol, the active form of vitamin D – Secrete renin ,e thropoietin Hea :-Cardiac muscle secretes natriuretic peptides decrease blood volume and blood pressure Stomach and small intestine secrete at least 10 enteric hormones Coordinate digestive motility and glandular e First & e Only Franchise in the Iraq Endocrine Disorders Copyright © 2014 John Wiley & Sons, Inc. All rights rese ed.