2Learning Objectives (1 of 2) Explain normal physiologic functions of pituitary hormones, common endocrine disturbances, and treatmentDescribe major thyroid abnormalities, clinical manifestations, and treatmentExplain normal physiologic functions of adrenal cortex and medulla, common disturbances, and treatmentDefine causes and effects of parathyroid dysfunction and treatment
3Learning Objectives (2 of 2) Discuss concept of ectopic hormone production by nonendocrine tumorsExplain adverse health effects of obesity, surgical procedures for obesity and their rationaleExplain stress and its effects on the endocrine system
4Endocrine Glands (1 of 2) Major endocrine glands Pituitary Thyroid ParathyroidAdrenal cortex and medullaPancreatic isletsOvaries and testes
5Endocrine Glands (2 of 2)Level of hormone in circulation: controls amount of hormone synthesized and released by an endocrine glandDisorders: hypersecretion or hyposecretionDetermination of clinical effectsDegree of dysfunctionAge and sex of affected individual
6Pituitary Gland (1 of 6)Suspended by stalk from hypothalamus at base of brainAnterior lobeIntermediate lobe: rudimentary structurePosterior lobeTropic hormones (regulate other endocrine glands)Regulated by level of hormone produced by the target glandSelf-regulating mechanism maintains uniform hormone outputProlactin secretion controlled by prolactin inhibitory factorThyroid stimulating hormone stimulates release of prolactin and thyroid hormones
7Pituitary Gland (2 of 6) Anterior lobe hormones Growth hormone: stimulates growth of tissuesProlactin: stimulates milk productionThyroid-stimulating hormone (TSH)Adrenocorticotrophic hormone (ACTH)Follicle-stimulating hormone (FSH)Luteinizing hormone (LH)Posterior lobe hormonesAntidiuretic hormone (ADH): causes more concentrated urineOxytocin: stimulates uterine contractions and milk secretion
8Normal mechanisms controlling elaboration of tropic hormones by the pituitary gland
9Pituitary Gland (3 of 6) Panhypopituitarism Pituitary dwarfism Anterior lobe fails to secrete all hormonesPituitary dwarfismDeficiency of growth hormoneCauses retarded growth and developmentDiabetes insipidusFailure of posterior lobe to secrete ADH or failure of kidney to respond to ADH (nephrogenic diabetes insipidus)Unable to absorb H2OCauses excretion of large amounts of diluted urineFrom a pituitary tumor
10Pituitary Gland (4 of 6) Growth hormone overproduction Caused by pituitary adenomaCauses gigantism in childrenCauses acromegaly in adultsMay cause visual disturbances from tumor encroachment in optic chiasmProlactin overproductionResult of small pituitary adenomaAlso from conditions affecting function of hypothalamusCauses amenorrhea and galactorrhea (milk secretion from non-pregnant breasts)
11Pituitary Gland (5 of 6) Pituitary tumors Many pituitary endocrine disturbances caused by anterior lobe pituitary tumorsClinical manifestations depend on size of tumor and the hormone producedFunctional tumors: produce hormones that cause clinical manifestationsNonfunctional tumors: do not produce hormones but exert other effectsMay encroach on important structures adjacent to optic chiasm; disrupt hormone-producing functions of anterior lobe cells
12Pituitary Gland (6 of 6) Pituitary tumors Treatment determined by type, size, and hormone produced by tumorDrugs to suppress tumor growthSurgical resection: usual surgical approach is through the nasal cavity (transsphenoidal resection)
16Thyroid Gland Structure Actions Two lateral lobes connected by isthmus Composed of thyroid follicles that produce and store hormonesHormone production regulated by TSH (thyroid stimulating hormone)Parafollicular cells: secrete calcitoninActionsControls rate of metabolic processesRequired for normal growth and development
17Normal thyroid gland, illustrating two lateral lobes connected by narrow isthmus
18Low-magnification photomicrograph of cellular structure of normal thyroid gland.
19High-magnification photomicrograph of normal thyroid follicles.
24Hyperthyroidism Toxic goiter or Graves disease Caused by antithyroid antibody that stimulates glandMimics effects of TSH but not subject to normal control mechanismsTreatmentAntithyroid drugs, thyroidectomy, large doses of radioactive iodine
28Hypothyroidism In adult In an infant Myxedema Causes metabolic slowing Treatment: administration of thyroid hormoneIn an infantCretinismCauses impaired growth and CNS developmentCauses hypometabolismEarly diagnosis and treatment required for normal development
29The characteristic appearance of neonatal hypothyroidism (cretinism) as a result of a congenital absence of thryroid gland.
31Chronic Thyroiditis or Hashimoto Thyroiditis Autoantibody destroys thyroid tissueResults in hypothyroidismAn immunologic reaction, not from an infectionCellular infiltration from an immunologic reaction between antigen and antibody
32Low-magnification photomicrograph of cellular structure in chronic thyroiditis.
34Radiation and Thyroid Tumors Radiation: increases incidence of benign and malignant thyroid tumors after latent period of 5-10 yearsMost tumors are well-differentiated and easily treatedPersons who received head or neck radiation should have periodic follow-up examinations
35A benign, well-circumscribed adenoma of the thyroid gland (arrows).
36Well-differentiated papillary carcinoma of thyroid Well-differentiated papillary carcinoma of thyroid. Higher magnification.
37Parathyroid GlandsBlood calcium level is in equilibrium with calcium in the boneActions: Calcium level: regulated by parathyroid glandsLow calcium in blood: causes tetany (increased neuromuscular excitability causing spasm of skeletal muscle)High calcium in blood: causes lowered neuromuscular excitability
38HyperparathyroidismUsually from a hormone-secreting parathyroid adenomaEffectsHypercalcemia: blood calcium risesRenal calculi: from excessive calcium excreted in urineCalcium deposition in tissuesDecalcification of bone: from excessive calcium withdrawn from boneTreatment: Removal of tumor
39HypoparathyroidismUsually from accidental removal of parathyroid glands during thyroid surgeryEffectsHypocalcemia: blood calcium falls precipitouslyLeads to neuromuscular excitability and tetanyTreatment: raise calcium levelsHigh-calcium dietSupplementary vitamin D
40Adrenal Cortex (1 of 2) Adrenals: paired glands above kidneys Hormones secreted by adrenal cortexGlucocorticoidsMineralocorticoidsAldosterone: major hormoneRenin-angiotensin system is main stimulusSex hormonesOverproduction of aldosteroneFrom aldosterone-producing tumor of adrenal cortexHigh sodium, blood volume, blood pressureLow potassium level leading to neuromuscular manifestations
41Adrenal Cortex (2 of 2) Overproduction of adrenal sex hormones Congenital adrenal hyperplasiaSex-hormone-producing tumors
42Adrenal MedullaProduces catecholamines that stimulate the sympathetic nervous systemNorepinephrine (noradrenaline)Epinephrine (adrenaline)Pheochromocytoma: increased secretion of catecholaminesProduces pronounced CV effectsMay cause cerebral hemorrhage from hypertensionAny emotional stress causes release of hormonesTreatment: tumor resection
43Biosynthesis of adrenal cortical hormones and the site of enzymatic block leading to overproduction of adrenal androgens.
44Addison Disease An adrenal cortical hypofunction Deficiency of all steroid hormonesGlucocorticoid deficiency: hypoglycemiaMineralocorticoid deficiency: lowblood volume and low blood pressureHyperpigmentation: from increased ACTH due to loss of feedback inhibitionAutoimmune disorderTreatment: administration of corticosteroids
45Appearance of hand (right side of photograph) of patient with Addison’s disease compared with hand of normal subject.
46Cushing Disease Excessive production of adrenal corticosteroids Causes Glucocorticoid excess: disturbed carbohydrate, fat, and protein metabolismMineralocorticoid excess: high blood volume and high blood pressureTreatment: tumor removalCausesHormone-producing pituitary microadenomaHormone-producing adrenal cortex adenomaHyperplastic adrenal glandsAdministration of large amounts of corticosteroidOther tumors
49Overproduction of Other Adrenal Cortex Hormones Overproduction of aldosteroneAldosterone secreting adenomaOverproduction of adrenal sex hormonesCongenital adrenal hyperplasiaAdrenal sex-hormone–producing tumor
50Pancreatic IsletsPancreatic tissue that functions as an endocrine glandProduce hormonesBeta cells: insulin productionAlpha cells: glucagonDelta cells: somatostatin
51Gonads Function Tumors may secrete hormones Production of germ cellsProduction of sex hormones: controlled by gonadotropic hormones of pituitary gland FSH and LHTumors may secrete hormonesTreatment: surgical excision
52Nonendocrine TumorsEctopic hormones: hormones secreted by nonendocrine tumors that are identical with or mimic action of true hormonesUsual origin: produced by malignant tumorsLung, pancreas, kidneys, connective tissue
53Stress and Endocrine System Stress: any event that disturbs homeostasisCauses: injury, surgery, prolonged exposure to cold, vigorous exercise, pain, or strong emotional stimulus such as anxiety or fearAcute response to stressFear-fight-flight reactionMediated by sympathetic nervous system and adrenal medullaChronic response to stress: alters metabolism, taxes CV system, impairs inflammatory and immune responsesInvolves adrenal cortex; predisposes to illness
54Obesity (1 of 2) Occurs when caloric intake > requirements Usually NOT result of endocrine or metabolic disturbanceHealth consequencesCardiovascular diseaseDiabetesCancerMusculoskeletal problemsImpaired pulmonary function
55Obesity (2 of 2) Treatment Medical: diet Drugs: suppress appetite Combination of fenfluramine and phentermine (fen-phen) causes heart valve damageSurgeryIleal bypass: several complications, infrequently performedGastric bypassVertical-banded gastroplasty