PH 131: Human Anatomy and Pathology with Pathophysiology - Endocrine System PDF

PH 131: HUMAN ANATOMY AND PATHOLOGY WITH PATHOPHYSIOLOGY ENDOCRINE SYSTEM Prof. Vivien Fe F. Fadrilan-Camacho Trans 2 OUTLINE...

PH 131: HUMAN ANATOMY AND PATHOLOGY WITH PATHOPHYSIOLOGY ENDOCRINE SYSTEM Prof. Vivien Fe F. Fadrilan-Camacho Trans 2 OUTLINE ENDOCRINE SYSTEM A. Endocrine System Nervous System vs. Endocrine System a. Functions Nervous System b. Exocrine vs Endocrine → Via electrochemical impulses c. Local Chemical Messengers B. Hormones → Responses in milliseconds a. Hormone Actions Endocrine System b. Chemical Structure → Via hormones c. Hormone Receptors → Responses occur after a lag period of seconds or d. Hormone Responses days; once initiated, responses are more prolonged e. Feedback Mechanisms i. Negative ii. Positive FUNCTIONS f. Hormone Clearance g. Endocrine Gland Stimuli 1. Water balance C. Hypothalamus a. Controls solute concentration of blood a. Hypothalamic Control over Endocrine 2. Uterine contractions and milk release Organs 3. Growth, metabolism, and tissue maturation D. The Pituitary Gland 4. Ion regulation a. Structure 5. Heart rate and blood pressure regulation b. Hormones of Posterior Pituitary 6. Blood glucose control i. Antidiuretic Hormone 7. Immune system regulation ii. Propiomelanocortin 8. Reproductive functions control iii. Melanocyte Stimulating Hormone, Endorphins, Lipotropins iv. Adrenocorticotrophic Hormone EXOCRINE VS. ENDOCRINE GLAND (ACTH) v. Growth Hormone (GH or Exocrine Gland Somatotropin) Glands with ducts; produces non-hormonal substances vi. LH, FSH, Prolactin → Membrane surface (e.g. sweat and salivary glands) E. Thyroid Gland a. Thyroid Hormones Endocrine Gland i. Thyrotropin (TSH) and Thyroid Ductless glands which produce hormones; Hormones b. Effects of T3 and T4 → Vascular and lymphatic drainage (e.g. pituitary, c. Regulation of Calcitonin Secretion thyroid, parathyroid, adrenal, pineal, and thymus d. Parathyroid Glands gland) e. Effects of Parathyroid Hormone → Hypothalamus: neuroendocrine organ F. Adrenal Glands → Organs with endocrine and exocrine products: a. Hormones of Adrenal Cortex ✔ Pancreas b. Adrenal Medulla G. Pancreas ✔ Ovaries and testes a. Glucagon b. Insulin c. Diabetes Mellitus (DM) H. Hormones of the Reproductive System a. Testosterone b. Estrogen and Progesterone I. Pineal Body J. Thymus Gland, GI Tract, Kidneys a. Thymosin b. GI Tract c. Kidneys Figure 1. Differences in the Anatomical Structures of the d. Adipose Tissue Exocrine and Endocrine Glands K. Hormone-like Substances a. Autocines b. Paracrines L. Thyroid Disorders a. Goiter b. Hyperthyroidism (Grave’s Disease) c. Hypothyroidism M. Public Health Interventions Transcribed by: Abagat, Balatero, Ecaldre, Flores, Joson, Paulino, 1 Ragonot  PH 131: HUMAN ANATOMY AND PATHOLOGY WITH PATHOPHYSIOLOGY ENDOCRINE SYSTEM Prof. Vivien Fe F. Fadrilan-Camacho Trans 2 5. Stimulates mitosis CHEMICAL STRUCTURE Proteins, Peptides and Amino Acid Derivatives Bind to membrane bound receptors (except thyroid hormones) → Proteins ✔ most hormones of the anterior pituitary glands → Peptide hormones ✔ hormones of the posterior pituitary glands → Amino acid derivatives ✔ chemically modified; hormones of adrenal medulla Lipid Hormones lipid soluble, which is the ability to dissolve through the Figure 2. Anatomical Loci of the Principal Endocrine Glands and lipid (fat) portion of a membrane Tissues → Steroid Hormones ✔ derived from cholesterol LOCAL CHEMICAL MESSENGERS ✔ hormones produced by the adrenal cortex and gonads INTERCELLULAR CHEMICAL SIGNALS ✔ diffuse across the cell membrane and bind to Autocrines intracellular receptor molecules - Exert effects on the Prostaglandins → Eicosanoids from Arachidonic Acid same cells that secrete Smooth muscle them ✔ include prostaglandins, prostacyclins, and contraction Paracrines - Produced by a wide leukotrienes Somatostatin variety of tissues and ✔ bound to membrane-bound receptors that Inhibits release of secreted into tissue are associated with G proteins insulin produced by spaces other cells - Act on surrounding cells STRUCTURAL CATEGORIES OF HORMONES - Secreted into blood by Structural Category Examples Hormone specialized cells Thyroxine, insulin - Influences specific Growth hormone activities Proteins Prolactin Insulin Neurohormone - Produced by neurons Oxytocin, antidiuretic and functions like Follicle-stimulating hormone Glycoproteins hormone hormones Luteinizing hormone (protein and Thyroid-stimulating hormone - Produced by neurons carbohydrates) Parathyroid hormone Neurotransmitter or and secreted by Neuromodulator presynaptic nerve Thyrotropin-releasing hormone Acetylcholine, terminals Oxytocin epinephrine - Influences postsynaptic Antidiuretic hormone cells Calcitonin Glucagon - Secreted into Adrenocorticotropic hormone Pheromone environment Polypeptides Endorphins Sex pheromones - Modifies physiology Thymosin and behavior Melanocyte-stimulating hormone Hypothalamic hormone HORMONES Lipotropins Somatostatin Chemical substances secreted by cells into extracellular Epinephrine fluids Amino Acid Norepinephrine Regulate the metabolic function of other cells in the Derivatives Thyroid hormones (both T3 and T4) body Melatonin Estrogen HORMONE ACTIONS Progestins (progesterone) 1. Alters plasma membrane permeability or membrane Steroids Testosterone potential by opening or closing ion channels Mineralocorticoids (aldosterone) Glucocorticoids (cortisol) 2. Stimulates synthesis of proteins or regulatory molecules (e.g. enzymes) Prostaglandins Thromboxanes 3. Actiavtes or deactivates enzymes Fatty Acid Derivatives Prostacyclins 4. Induces secretory activity Leukotrienes Transcribed by: Abagat, Balatero, Ecaldre, Flores, Joson, Paulino, 2 Ragonot  PH 131: HUMAN ANATOMY AND PATHOLOGY WITH PATHOPHYSIOLOGY ENDOCRINE SYSTEM Prof. Vivien Fe F. Fadrilan-Camacho Trans 2 Positive Feedback Mechanism HORMONE RECEPTORS Occurs when biological action of the hormone causes additional secretion of the hormone Membrane-bound Receptors Luteinizing hormone (LH) is released as a result of the Receptor sites on the outer surface of the cell stimulatory effect of estrogen on the anterior pituitary membrane before ovulation. Interact with large and water-soluble molecules → LH → ovaries → estrogen → LH → Receptors that directly alter membrane → After LH reaches an appropriate concentration, it permeability exhibits negative feedback. ✔ opening and closing of ion channels ✔ e.g. Acetylcholine (Ach) and Na+ channels in skeletal muscle membranes → Receptors that directly alter the activity of enzymes ✔ increase or decrease of enzyme activities through the increase or decrease activity of cyclic guanosine monophosphate (cGMP) → Receptors and G proteins ✔ activation of G proteins (complex proteins) ✔ inactive G protein (with α, β, σ subunits) ✔ GDP is bound to α subunit ✔ receptor binding the α subunit separates from the β and σ, then GTP replaces GDP can open or close channels Figure 3. Feedback Mechanism of Menstrual Cycle (Ovulation) activate enzymes affect gene expression HORMONE CLEARANCE Intracellular Receptors 1. metabolic destruction by the tissues Located in the cytoplasm or nucleus of the cell 2. binding with the tissues Interact with small, lipid intercellular signals 3. excretion by the liver into the bile 4. excretion by the kidneys into the urine HORMONE RESPONSES ENDOCRINE GLAND STIMULI 1. Permissiveness 1. Humoral a. situation when one hormone cannot exert its a. direct response to changing blood levels full effects without another hormone being b. e.g. parathyroid hormone, insulin and present aldosterone b. e.g. thyroid hormone on reproductive system 2. Neural 2. Synergism a. stimulated by nerve fibers a. occurs where more than one hormone b. e.g. catecholamines produces the same effects at the target cell 3. Hormonal and their combined effects are amplified a. in response to hormones produced by other (1+1 = 2) endocrine organs b. e.g. glucagon and epinephrine b. e.g. hypothalamic-pituitary axis 3. Antagonism a. one hormone opposes the action of another hormone b. e.g. insulin and glucagon FEEDBACK MECHANISMS Negative Feedback Mechanism Ensure a proper level of hormone activity at the target tissue After a stimulus causes release of the hormone, products resulting from the action of the hormone tend to suppress its further release. The hormone has a negative feedback effect to prevent oversecretion of the hormone or overactivity Figure 4. Different Endocrine Gland Stimuli Transcribed by: Abagat, Balatero, Ecaldre, Flores, Joson, Paulino, 3 Ragonot  PH 131: HUMAN ANATOMY AND PATHOLOGY WITH PATHOPHYSIOLOGY ENDOCRINE SYSTEM Prof. Vivien Fe F. Fadrilan-Camacho Trans 2 HYPOTHALAMUS THE PITUITARY GLAND A neuro-endocrine organ; regulates the nervous system and endocrine system activities by 3 different Pea on a stalk (infundibulum) mechanisms: Controlled by hypothalamus → It secretes regulatory hormones that control Consists of two lobes: the neurohypophysis (posterior endocrine cells in the adenohypophysis (anterior lobe) and the adenohypophysis (anterior lobe) lobe) of the pituitary gland: ✔ Releasing hormones (RH) that stimulate production of one or more hormones ✔ Inhibiting hormones (IH) that prevent the synthesis and secretion of specific pituitary hormone → acts as an endocrine organ, releasing the hormones ADH and oxytocin into the circulation at the neurohypophysis (posterior lobe) → contains autonomic centers that have direct neural control over the endocrine cells of the suprarenal medulla → sympathetic division is activated → medulla → hormones Autonomic centers are either sympathetic Figure 7.1. Pituitary Gland Structure or parasympathetic that have direct neural control over the endocrine cells of the adrenal or suprarenal gland (on top of the kidney). The adrenal or suprarenal gland has cortex (outer) and medulla (inner). The medulla releases epinephrine and norepinephrine. Figure 7.2. Pituitary Gland Structure POSTERIOR PITUITARY (NEUROHYPOPHYSIS) Connected to the hypothalamus through a group of neurons known as hypothalamic-hypophyseal tract and releases neurohormones (oxytocin and ADH) (Note: The term “tract” means or is related to a group of neurons) Figure 5. Hypothalamic Control over Endocrine Organs → Paraventricular neurons in this tract secretes oxytocin → Supraoptic neurons in this tract secretes antidiuretic hormone (ADH) ANTERIOR PITUITARY (ADENOHYPOPHYSIS) Connected to the hypothalamus through hypophyseal portal system or the bloodstream (Note: The term “portal” is related to blood) Secretes releasing and inhibitory hormones Consists of three areas with indistinct boundaries: pars distalis, pars intermedia, and pars tuberalis Figure 6. Hormones of the Hypothalamus Transcribed by: Abagat, Balatero, Ecaldre, Flores, Joson, Paulino, 4 Ragonot  PH 131: HUMAN ANATOMY AND PATHOLOGY WITH PATHOPHYSIOLOGY ENDOCRINE SYSTEM Prof. Vivien Fe F. Fadrilan-Camacho Trans 2 HORMONES OF THE PITUITARY GLAND → Specialized neurons found in walls of atria of heart, large veins, carotid arteries, and aortic arch → Sense changes in blood pressure ✔ If BP decreases, then ADH secretion is stimulates Figure 8.1. Hormones of the Pituitary Gland Figure 10. Control of ADH Secretion Figure 8.2. Hormones of the Pituitary Gland Figure 8.3. Hormones of the Pituitary Gland Figure 11. Control of Oxytocin Secretion Propiomelanocortin (POMC) Prohormone (not totally a hormone )from the anterior pituitary Source of ACTH, enkephalin, beta-endorphin, lipotropin Source of melanocyte-stimulating hormone (CNS neurotransmitter involved in appetite control) Melanocyte Stimulating Hormone, Endorphins, Lipotropins ACTH, MSH, endorphins, and lipotropins all derived from the same large precursor molecule when Figure 9. Associated Pathways in the Pituitary Gland stimulated by CRH Melanocyte Stimulating Hormone (MSH) HORMONES OF POSTERIOR PITUITARY → causes melanocyte to produce more melanin Antidiuretic Hormone (Vasopressin) Endorphins Osmoreceptors → act as an analgesic (pain reliever) → Specialized neurons of hypothalamus monitor → produced during times of stress changes in intercellular osmolality (solute Lipotropins concentration) → Cause adipose cells to catabolize fat ✔ If the concentration of electrolytes increases or if the concentration of water decreases, then Adrenocorticotrophic Hormone (ACTH) ADH secretion is stimulated CRH from hypothalamus causes release of ACTH from Baroreceptors anterior pituitary Transcribed by: Abagat, Balatero, Ecaldre, Flores, Joson, Paulino, 5 Ragonot  PH 131: HUMAN ANATOMY AND PATHOLOGY WITH PATHOPHYSIOLOGY ENDOCRINE SYSTEM Prof. Vivien Fe F. Fadrilan-Camacho Trans 2 → Causes cortisol (stress hormone) secretion from the GnRH from hypothalamus stimulates LH and FSH adrenal cortex (a glucocorticoid from the zona secretion fasciculata) – against stress Prolactin → Causes aldosterone secretion from the adrenal → Role in milk production cortex (a mineralocorticoid from the zona → Regulation of secretion: prolactin-releasing glomerulosa) hormone (PRH) and prolactin-inhibiting hormones → Binds directly to melanocytes of the skin (PIH) ✔ Causes increase in production of melanin THYROID GLAND Growth Hormone (GH or Somatotropin) Highly vascular Stimulates uptake of amino acids; protein synthesis; Iodine enters follicular cells by active transport growth in most tissues → Only glands that stores hormone Stimulates breakdown of fats to be used as an energy Histology source → Composed of follicles (follicular cells surrounding → But stimulates synthesis of glycogen (glucose thyroglobulin/thyroid hormones) sparing) → Parafollicular cells: between follicles Promotes bone and cartilage growth Follicular cells secrete thyroglobulin into the lumen of Regulates blood levels of nutrients after a meal and the follicle during periods of fasting → iodine and tyrosine necessary for production of T3 Stimulates glucose synthesis by liver and T4 → hormones stored here attached to the thyroglobulin then absorbed into follicular cells → hormones disattached from thyroglobulin and released into circulation Parafollicular cells -> secrete calcitonin which reduces [Ca2+] in body fluids when Ca levels Figure 12. Growth Hormone Effects and Mechanisms Figure 14. Cellular anatomy of the thyroid gland. THYROID HORMONES Only free thyroxine and T3 can enter cell; → bound-thyroxine serves as a reservoir of this hormone 33–40% of T4 converted to T3 in cells T3 more potent Bind with intracellular receptor molecules and initiate Figure 13. Regulation of GH Secretion new protein synthesis LH, FSH, Prolactin Normal growth of many tissues dependent on presence of thyroid hormones Gonadotropins → Glycoprotein hormones that promote growth and Thyrotropin (TSH) and Thyroid Hormones function of the gonads TRH from hypothalamus causes release of TSH from LH and FSH anterior pituitary → Both hormones regulate production of gametes → Causes secretion and storage of hormones T3 and and reproductive hormones T4 from and within the thyroid gland ✔ Testosterone in males → T3 and T4 inhibit TRH and TSH secretion ✔ Estrogen and progesterone in females Transcribed by: Abagat, Balatero, Ecaldre, Flores, Joson, Paulino, 6 Ragonot  PH 131: HUMAN ANATOMY AND PATHOLOGY WITH PATHOPHYSIOLOGY ENDOCRINE SYSTEM Prof. Vivien Fe F. Fadrilan-Camacho Trans 2 Effects of T3 and T4 → regulation depends on calcium levels Maintain normal rate of metabolism. Increase the rate at which glucose, fat, and protein are metabolized Increase the activity of Na+-K+ pump which increases body temperature. Can alter the number and activity of mitochondria resulting in greater ATP synthesis and heat production. Normal growth and maturation of bone, hair, teeth, c.t., and nervous tissue require thyroid hormone. Both T3 and T4 play a permissive role for growth hormone Figure 17. Effects of parathyroid hormone. ADRENAL GLANDS Near superior poles of kidneys; retroperitoneal (area in the back of the abdomen behind the peritoneum) Inner medulla; outer cortex Medulla: Secretes epinephrine and norepinephrine Figure 15. Hormones of the thyroid and parathyroid glands. Figure 18. Adrenal layers. Cortex: three zones from superficial to deep: 1. Zona glomerulosa Figure 16. Regulation of thyroid hormones. 2. Zona fasciculata Regulation of Calcitonin Secretion 3. Zona reticularis Produced by parafollicular cells HORMONES OF ADRENAL CORTEX Secretion triggered by high Ca2+ concentration in blood; → acts to decrease Ca2+ concentration Mineralocorticoids: Zona glomerulosa Primary target tissue → bone → Aldosterone - rate of sodium reabsorption by kidneys sodium blood levels Decreases osteoclast activity, lengthens the life span of osteoblasts Glucocorticoids: Zona fasciculata → Cortisol - fat and protein breakdown, PARATHYROID GLANDS h-glucose synthesis, inflammatory response Secrete PTH: target tissues → bone, kidneys, and Androgens: Zona reticularis intestines → Weak androgens are secreted and then → increases blood calcium and phosphate levels converted to testosterone by peripheral tissues → stimulates osteoclasts → Stimulate pubic and axillary hair growth and sexual drive in females → promotes calcium reabsorption by kidneys and PO4 excretion ADRENAL MEDULLA → increases synthesis of vitamin D Neurohormones: epinephrine and norepinephrine h-absorption of Ca and PO4 by Combine with adrenergic membrane-bound receptors intestines Transcribed by: Abagat, Balatero, Ecaldre, Flores, Joson, Paulino, 7 Ragonot  PH 131: HUMAN ANATOMY AND PATHOLOGY WITH PATHOPHYSIOLOGY ENDOCRINE SYSTEM Prof. Vivien Fe F. Fadrilan-Camacho Trans 2 All function through G-protein mechanisms Secretion of hormones prepares the body for physical activity Effects are short-lived; hormones rapidly metabolized Epinephrine: → increase blood levels of glucose → increase fat breakdown in adipose tissues → causes dilation of blood vessels in skeletal muscles and cardiac muscles Epinephrine and norepinephrine increase heart rate and force of contraction; cause blood vessels to constrict in skin, kidneys, GI tract, and other viscera Figure 21. The Pancreas HORMONES OF THE PANCREAS Glucagon Major target is the liver Promotes: → Glycogenolysis ✔ Breakdown of glycogen to glucose Figure 19. Regulation of Adrenal Medullary Secretions → Gluconeogenesis ✔ Synthesis of glucose from lactic acids and noncarbohydrates → Release of glucose to the blood from liver cells Insulin Target tissues: → Liver → Adipose tissue → Muscle → Satiety center of hypothalamus Lowers blood glucose levels Enhances transport of glucose into body cells Figure 20. Stress and the Adrenal Gland Counters metabolic activity that would enhance blood glucose levels PANCREAS PANCREATIC HORMONES Retroperitoneal Islets Hormone Structure Target tissue Response Increased Exocrine gland Liver uptake and → Produces pancreatic and digestive juices Beta Skeletal Insulin Protein use of (β) muscle Endocrine gland glucose and Fat tissue amino acid → Consists of pancreatic islets Increased → Composed of breakdown of ✔ Alpha cells glycogen Alpha Glucagon Polypeptide Liver Release of Secrete glucagon (ɑ) glucose into ✔ Beta cells the circulatory system Secrete insulin ɑ and β cells ✔ Delta cells (some Inhibition of Secrete somatostatin somatostatin Delta Somato- insulin & Peptide is produced (δ) statin glucagon in the secretion hypothalamu s) Transcribed by: Abagat, Balatero, Ecaldre, Flores, Joson, Paulino, 8 Ragonot  PH 131: HUMAN ANATOMY AND PATHOLOGY WITH PATHOPHYSIOLOGY ENDOCRINE SYSTEM Prof. Vivien Fe F. Fadrilan-Camacho Trans 2 → development and maintenance of male EFFECT OF INSULIN & GLUCAGON ON TARGET TISSUES reproductive organs and secondary sex Target Tissue Response to Insulin Response to Glucagon characteristics Skeletal muscle Cardiac muscle Inhibin Bone ↑ glucose uptake → Inhibits FSH secretion Fibroblasts ↑ uptake of certain Little effect Leukocytes amino acids FEMALE: OVARIES Mammary glands Rapid ↑ in breakdown of Estrogen and Progesterone glycogen to glucose Regulates: (glycogenolysis) and release of glucose into → Uterine and mammary gland development and ↑ glycogen synthesis the blood function ↑ use of glucose for ↑ glucose formation Liver energy (glycolysis) (gluconeogenesis) from → External genitalia structure amino acids and to → Secondary sex characteristics some degree in fats ↑ metabolism of fatty → Menstrual cycle acids = ↑ ketones in the blood Inhibin ↑ glucose uptake, → Inhibits FSH secretion ↑ conc. = breakdown of glycogen synthesis, fat fats (lipolysis) Relaxin Adipose cells synthesis, and fatty Probably unimportant acid uptake → Increases flexibility of symphysis pubis under most conditions ↑ glycolysis Little effect except to ↑ Nervous system glucose uptake in the No effect satiety center Figure 23. Hormones of the Reproductive Organs PINEAL BODY In epithalamus Figure 22. Regulation of Blood Glucose Levels Produces melatonin DIABETES MELLITUS (DM) Results from hyposecretion or hypoactivity of insulin 3 cardinal signs → Polyuria ✔ Huge urine output → Polydipsia ✔ Excessive thirst → Polyphagia ✔ Excessive hunger or food consumption Hyperinsulinism → Excessive insulin secretion Figure 24. Pineal body → Resulting in hypoglycemia HORMONES OF THE REPRODUCTIVE SYSTEM THYMUS GLAND, GI TRACT, KIDNEYS Thymosin MALE: TESTES Aids in the developments of the immune system. Testosterone GI Tract Regulates: Has several hormones that regulate digestion and → production of sperm cells enzyme secretion. Transcribed by: Abagat, Balatero, Ecaldre, Flores, Joson, Paulino, 9 Ragonot  PH 131: HUMAN ANATOMY AND PATHOLOGY WITH PATHOPHYSIOLOGY ENDOCRINE SYSTEM Prof. Vivien Fe F. Fadrilan-Camacho Trans 2 Kidneys Foods such as: Secrete erythropoietin → Cabbage → Signals RBC production → Turnip → Soy Adipose Tissue → Kale Releases leptin → Cassava → Involved in the sensation of satiety → Sweet Potato → Stimulates increased energy expenditure. → Kale → Radish HORMONE-LIKE SUBSTANCES → Lima Beans → Cauliflower Autocrines → Millet Chemical signals released by a cell that affects the → Broccoli same cell. → Brussel Sprouts Chemical mediators of inflammation which are modified fatty acids: eicosanoids such as Toxic Goiter → Prostaglandins Hyperthyroid condition resulting from hyperactivity of → Thromboxanes the thyroid gland due to excessive stimulation by TSH → Prostacyclins that produces a large nodular gland. → Leukotrienes Goiter Development Paracrines Chemical signals released into intercellular fluid that affects nearby cells. → Endorphins (for pain modulation) → Enkephalins (for pain modulation) → Several growth factors THYROID DISORDERS GOITER Enlargement of the thyroid gland, often visible on the anterior neck. Caused by various hypothyroid and hyperthyroid conditions. Can be very large, compressing the esophagus and interfering with swallowing. Can cause pressure on the trachea. Figure 25. Endemic Goiter and Hypothyroidism Development Endemic Goiter HYPERTHYROIDISM (GRAVE’S DISEASE) May affect large groups of people in a specific geographical area. Increased T3 and T4 secretion. Occurs in regions with low iodine levels in the soil and Occurs more frequently in women over 30 years old. food. Related to an autoimmune factor. → Mountainous areas Though there is a risk of developing hypothyroidism or → Around the Great Lakes hypoparathyroidism, the following are the treatments: Iodine is “trapped” by the thyroid gland and used to → Radioactive Iodine synthesize T3 and thyroxine T4. → Surgical removal of thyroid gland Leads to low T3 and T4 production and an increase in → Use of antithyroid drugs TSH from the pituitary gland, produces: Exophthalmos → Hyperplasia → Hypertrophy Evident by the presence of protruding, staring eyes and decreased blink and eye movements Goitrogens Due to increased tissue mass in the orbit pushing Foods with elements that block T3 and T4 synthesis but eyeballs forward and from increased sympathetic increases TSH secretion. stimulation affecting the eyelids. Lithium and fluoride may be goitrogenic. Transcribed by: Abagat, Balatero, Ecaldre, Flores, Joson, Paulino, 10 Ragonot  PH 131: HUMAN ANATOMY AND PATHOLOGY WITH PATHOPHYSIOLOGY ENDOCRINE SYSTEM Prof. Vivien Fe F. Fadrilan-Camacho Trans 2 If left untreated, visual impairment may result from optic Primary Prevention nerve damage or corneal ulceration. No smoking. Thyrotoxic Crisis or Thyroid Storm → Increases risk of Grave’s disease. Acute situation of uncontrolled hyperthyroidism, usually Secondary Prevention precipitated by infection or surgery. Newborn screening. Life threatening due to the resulting: Thyroid disorder medical/surgical management. → Hyperthermia → Tachycardia → Heart Failure → Delirium HYPOTHYROIDISM Hashimoto’s Thyroiditis A destructive autoimmune disorder. Thyroid gland is gradually destroyed due to reactions made by the immune system against the thyroid gland. Myxedema Severe hypothyroidism in adults. Nonpitting edema manifested as facial puffiness and thick tongue. Myxedema coma: acute hypothyroidism resulting in: → Hypotension → Hypoglycemia → Hypothermia → Loss of consciousness → Life-threatening complications in undiagnosed or untreated elderly patients. Cretinism Untreated congenital hypothyroidism Either related to iodine deficiency during pregnancy or developmental defect. Thyroid gland is nonfunctional or absent. Neonatal screening aids in early treatment and prevents mental retardation that accompanies early hypothyroidism. Thyroid hormone affects cell metabolism, thus may affect growth and development due to severe impairment if left untreated. Child may be faced with the following: → Difficulty feeding → Delayed tooth eruption → Malocclusion → Large protruding tongue → Demonstrating stunted skeletal growth → Extreme lethargy PUBLIC HEALTH INTERVENTIONS Primordial Iodine Nutrition. → Salt iodization Eliminate thyroid disruptors. → Endocrine disrupting chemicals → PCBs, cyanide, DDT Transcribed by: Abagat, Balatero, Ecaldre, Flores, Joson, Paulino, 11 Ragonot