L. Aya M. Serry Endocrine System & Its Disorders 2016 Pathophysiology L. Aya M. Serry Endocrine System & Its Disorders 2016

Lecture Objectives Identify the endocrine system Recognize the endocrine glands and their Hormones Functions of the endocrine Hormones Disorders of the endocrine functions

ENDOCRINE SYSTEM System of ductless glands Regulates body functions via hormones secreted into the bloodstream.

ENDOCRINE SYSTEM Major Endocrine Glands: Hypothalamus Pituitary Gland Thyroid Gland Parathyroid Gland Thymus Adrenal Gland

ENDOCRINE SYSTEM Other organs containing endocrine tissue: Pancreas Kidneys Heart Digestive Tract Placenta Testes Ovaries Pineal Gland

HYPOTHALAMUS ‘Master Gland’ Function : Control centre Attached to roof of third ventricle, near thalamus Continuously receive information on status of body systems via nerve impulses Monitors composition & temperature of blood Messages interpreted, evaluated : outgoing messages dispatched via nerves / hormones Plays role in feedback systems that govern secretions of endocrine system

2. PITUITARY GLAND Pea sized mass of glandular tissue Lies in sella turcica Slender stalk: Infundibulum connects pituitary gland to hypothalamus 2 parts : Neurohypophysis Adenohypophysis Indirectly controls : Growth Metabolism Sexual reproduction Lactation

PITUITARY GLAND: PARTS Neurohypophysis Adenohypophysis Small posterior lobe Large anterior lobe Stores hormones Releases hormones Oxytocin Growth hormone (GH) Anti Diuretic hormone (ADH) Thyroid Stimulating hormone (TSH) Adenocorticotropic hormone (ACTH) Lutenizing hormone (LH) Follicle stimulating hormone (FSH) Melanocyte stimulating hormone (MSH) Prolactin (PRL)

PITUITARY GLAND: HORMONES EFFECTS Oxytocin (OC) Stimulates contraction of uterus & contractile cells of breast ADH Prevents excess urine production GH General body growth ACTH Stimulate adrenal cortex to release hormone TSH Controls thyroid gland LH Stimulates sexual & reproductive function FSH Stimulate production of sperm & egg in ovaries & testis MSH Related to skin pigmentation PRL Initiates milk production in breast Anterior Pituitary Posterior Pituitary Anterior Pituitary Anterior Pituitary

THYROID GLAND ↑ in size : puberty & pregnancy Located in middle anterior part of neck: below larynx, in front of trachea “Butterfly” shape 2 lobes connected by isthmus ↑ in size : puberty & pregnancy Rich blood supply: able to deliver high levels of hormones in short period of time Produces Thyroxin (T4) & Tri-iodothyronine (T3) Calcitonin : involved in calcium & phosphate homeostasis

PARATHYROID GLAND Small rounded mass Attached to posterior surface of thyroid gland Produces Parathyroid hormone (PTH) Controls homeostasis of calcium & phosphate in blood by activating Vitamin D

THYMUS Plays a role in the immune system Produces thymosin, thymic humaral factor & thymic factor Responsible for maturation of T-lymphocytes

HARMONES OF THYROID, PARATHYROID & THYMUS ORGAN HORMONE EFFECT Thyroid gland (Follicular cells) T3 & T4 energy utilization oxygen consumption growth & development Thyroid gland (C cells) Calcitonin  Calcium ion concentration in body fluids Parathyroid PTH  Calcium ion concentration in body fluids Thymus Thymosin Maturation & functional competence of immune system 

ADRENAL GLAND Located superior to the kidney Divided into: (i) outer cortex (ii) inner medulla

ADRENAL GLAND ADRENAL CORTEX ADRENAL MEDULLA Secretes steroid hormones Secretes hormones controlled by ANS Glucocorticoids (metabolism) eg. cortisol Epinephrine (Adrenaline) Mineralocorticoids (homeostasis of ions) eg. Aldosterone Norepinephrine (Noradrenaline) Gonadocorticoids (oestrogens & androgens)

ADRENAL HORMONES REGION HARMONES EFFECT Cortex 1. Zona glomerulos Mineralocorticoid: Aldosterone Renal reabsorption of sodium ions & water. renal potassium ion loss 2. Zona fasciculata Glucocorticoid: cortisol Releases amino acids from skeletal muscle & lipids from adipose. Promotes liver glycogen & glucose formation Anti inflammatory effect 3. Zona Reticularis Androgens Medulla Epinephrine (Adrenaline), Norepinephrine (Noradrenaline) cardiac activity blood pressure glycogen breakdown blood glucose

PANCREAS Flattened organ Posterior to stomach, between doudenum on right & spleen on left Classified as exocrine & endocrine Hormones: Islets of Langerhans secrete: Glucagon,  cells :  blood glucose Insulin,  cells:  blood glucose Growth hormone inhibiting hormone (GHIH),  cells : inhibits glucagon & insulin

HORMONES OF PANCREAS CELLS HARMONE EFFECT Alpha () cells Glucagon Glucose synthesis & glycogen breakdown in liver  Blood glucose concentration Beta () cells Insulin Stimulation of lipids & glycogen storage & formation  Blood glucose concentration Delta () cells Somatostatin Inhibits secretion of insulin & glucagon

TESTES & OVARIES TESTES: Located within scrotum Produce testosterone Stimulates development of male sexual characteristics OVARIES: Located in pelvic cavity Produce oestrogen & progesterone Responsible for development & maintenance of female characteristics & menstrual cycle

HORMONES OF REPRODUCTIVE SYSTEM CELLS HORMONES EFFECT Testes Interstitial cells 1. Testosterone 2. Inhibin 1. Maturation of sperm Male secondary sex characteristics 2. Inhibits secretion of FSH Ovaries Follicle cells 1. Oestrogen 1. Follicle maturation Female secondary sex characteristic Corpus Luteum Progesterone Prepare uterus for implantation Prepare breast for secretory function

OTHER ENDOCRINE TISSUES KIDNEYS: Renal Erythropoietic factor: erythropoietin HEART: Atrial Natriuretic factor (ANF) GIT: Stomach gastrin, enteric gastrin, secretin, cholecystokinin, enterocinin, gastric inhibiting hormone PLACENTA: Human chorionic gonadotropin, oestrogen, progesterone, relaxin

Endocrine Disorders

Thyroid Gland Hormone: Thyroxin Over-activity (Too much hormone) Increased metabolic rate Increased food intake but loss of weight Hyperthyroidism (Grave’s Disease) Goiter (swollen neck, maybe bulging eyes)

Goiter

Thyroid Gland Hormone: Thyroxin Under-activity (Not enough hormone) Hypothyroidism (Hashimoto’s disease) - Reduced metabolic rate Low food intake but gain of weight Myxedema (when onset in adults) Cretinism (when onset in children) Can also cause a goiter

Myxedema Puffiness (swelling) Fatigue Obesity Dry, thickened skin Mental impairment Thin, brittle hair

Cretinism Protuberant abdomen Short Stature Infertility Neurological impairment Constant Fatigue Obesity

Thyroid Gland Hormone: Calcitonin Over-activity - Increased Bone Ca++, decreased Blood Ca++ Tetany (nerve problems leading to muscle spasms or cramps) Under-activity - Increase Blood Ca++, decreased Bone Ca++ Osteoporosis (brittle bones) Kidney stones

Parathyroid Gland Under-activity Over-activity Hormone: Parathormone (PTH) Under-activity Low Blood calcium, High Bone Ca++ Tetany Over-activity High Blood calcium, Low Bone Ca++ Osteoporosis

Pancrease Hormone: Insulin Over-activity Low blood sugar level ( ↓BSL) Hypoglycemia Under-activity High blood sugar level ( ↑BSL) Hyperglycemia Diabetes

Pancrease Hormone: Glucagon Over-activity High blood sugar level ( ↑BSL) Diabetes Under-activity Low blood sugar level ( ↓BSL) Hyper insulinism

Anterior Pituitary Gland Hormone: Growth Hormone Overactive Gigantism (children - very tall) Acromegaly (adults - bones & skin thicken) Underactive - Dwarfism (very short)

Giantism

Acromegaly

Dwarfism Dwarfism occurs when there is short supply of GH in childhood.

Endocrine Disorders Summary

Thyroxin – increases metabolic rate Overactive Goitre Hyperthyroidism Grave’s Disease Underactive Goitre Hypothyroidism Myxedema (adults) Cretinism (kids)

Calcitonin – Inc. Ca uptake by bones and dec. Ca level in blood Overactive Tetany Underactive Kidney Stones Osteoporosis

Parathormone (PTH) – inc. Ca level in blood, dec. Ca level in bone Overactive Kidney Stones Osteoporosis Underactive Tetany

Insulin – dec. blood sugar levels Overactive Hypoglycemia Hyperinsulinism (insulin shock) Underactive Hyperglycemia Diabetes

Calcitonin Vs. Parathormone Over Reactivity Under Reactivity Blood Ca Blood Ca Blood Ca Blood Ca Tetany Osteoporosis Kidney Stones Blood Ca Blood Ca Tetany Osteoporosis Kidney Stones

Glucagon – inc. blood sugar levels Overactive Hyperglycemia Diabetes Underactive Hypoglycemia Hyperinsulinism

Insulin vs Glucagon Insulin – Glucagon - Over Reactivity Under Reactivity BSL BSL Hypoglycemia BSL BSL Hyperglycemia Diabetes BSL Hyperglycemia Diabetes Hypoglycemia BSL

GH - Growth Hormone – increases bone growth Overactive Giantism (children) Acromegaly (adults) Underactive Dwarfism

MSH - Melanocyte Stimulating Hormone – causes color cells (melanocytes) in skin to darken Overactive Skin darkens Under active Skin will not darken Most severe condition is albinism

LH, FSH, ICTH – sex hormones in males and females that aid in sperm or egg (gamete) production Overactive Unknown Underactive Sterility