Chapter 4 Lesson 4.1

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 1 The Endocrine System  uses powerful chemical messengers called hormones to:  maintain homeostasis  respond to stress  regulate essential functions  control metabolic rate  direct growth and development

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 2  pituitary  thyroid  parathyroid  adrenal  pancreas  ovaries/testes  pineal  thymus Major glands of the endocrine system are:

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 3  are either amino acids (proteins) or steroids  are secreted into the bloodstream by specialized glands  target their actions to very specific tissue receptor sites Hormones are chemical messengers that:

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 4 Important hormones include:  insulin and glucagon  estrogen, progesterone, and testosterone  thyroxine, calcitonin, and thyroid stimulating hormone (TSH)  vasopressin  cortisol and cortisone  aldosterone  growth hormone (GH)  follicle stimulating hormone (FSH) and luteinizing hormone (LH)

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 5 Negative Feedback  Hormonal secretions typically regulated by negative feedback; information about the hormone level or its effect is fed back to the gland, which then responds accordingly

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 6 The effect of pituitary hormones on target tissues

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 7 Pituitary Gland Diseases Hyperpituitarism: Chronic, progressive disease caused by excessive production and secretion of pituitary hormones, especially growth hormone (HGH)

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 8 Types of Hyperpituitarism  Gigantism: increased growth hormone — occurs prior to puberty  Treatment focuses on reducing secreted hGH through radiation or surgical intervention to reduce pituitary size  Acromegaly: increased growth hormone — occurs after puberty is complete  Treatment focuses on reversing or preventing tumor mass effects and reducing secreted GH ideally through surgery with or without radiation to the pituitary gland.

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 9 Hypopituitarism  A deficiency or absence of the hormones produced by the pituitary gland, especially those of the anterior pituitary.  The cause of hypopituitarism may be a tumor or the pituitary or hypothalamus. Headache and blindness may be symptoms of tumor compression of the adjacent optic nerve.  Cause of panhypopituitarism is sometimes unknown; it is more common in women.  Treatment, based on patient age, severity and type, and underlying cause, includes removal of tumor and hormone replacement therapy.

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 10 Example of Hypopituitarism Dwarfism: abnormal underdevelopment that occurs in children due to decreased growth hormone production Treatment  Somatotropin (hGH) administration  Replacement of thyroid and adrenal hormones  Sex hormones as puberty approaches as necessary

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 11 Diabetes Insipidus  A deficiency in the release of vasopressin (ADH) from the posterior pituitary resulting in excessive (polyuria) urine excretion and thirst (polydipsia)  Treatment consists of vasopressin injections, nasal spray or oral desmopressin acetate.

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 12 Thyroid Gland Diseases  A group of disorders caused by increased or decreased amounts of thyroid hormones:  Simple goiter  Hashimoto disease  Hyperthyroidism/Graves’ disease  Hypothyroidism  myxedema

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 13 Hypofunction  bradycardia  constipation  weight gain  reduced alertness  fatigue  edema/bloating  poor circulation  cold intolerance  dry skin and hair Hyperfunction  tachycardia/palpitations  diarrhea  weight loss  anxiety/restlessness  fatigue  appetite  sweating  heat intolerance  hair loss Thyroid Gland Diseases Symptoms

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 14 Simple Goiter Enlargement of the thyroid gland: usually palpable results from shortage of dietary iodine  Symptoms include swollen mass (goiter) at anterior aspect of neck, and dyspnea and difficulty swallowing with further enlargement of goiter.  Treatment includes one drop per week of potassium iodide

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 15 Thyroid Gland Diseases: Hyperthyroidism Graves’ disease: diffuse goiter and over-production of thyroid hormone that can result in life-threatening condition  Causes of Graves’ disease are unknown but it is thought to be autoimmune in nature and there is a strong familial predisposition for it.  Exophthalmos, the outward protrusion of the eyeball, can be present with Graves’ disease. Other symptoms include rapid heartbeat, insomnia, and weightloss, to name a few.  Treatment goal is to reduce thyroid hormone through antithyroid drugs and beta-blockers, or for severe cases, radioactive iodine or surgery.

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 16 Thyroid Gland Diseases: Hypothyroidism Cretinism: a congenital condition in children in which the thyroid gland is absent or nonfunctional resulting in mental or growth retardation  Treated with thyroid hormone throughout life Myxedema: severe condition that develops in older child or adult; can result in life-threatening symptoms including myxedema coma  Symptoms include slowed metabolism, menorrhagia, weight gain, muscular weakness, and tiredness amongst others  Treatment includes administration of levothyroxine sodium

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 17  Painless lump or nodule on the thyroid gland that is malignant.  Treatment is usually surgery to remove the thyroid gland and any involved lymph nodes and replacement hormone.  Anaplastic types may only be treated with radiation and chemotherapy to prolong survival. Thyroid Gland Diseases: Thyroid Cancer

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 18 Parathyroid Gland Disease  Hyperparathyroidism  overproduction of PTH hormone, resulting in demineralization of bone and release of excess calcium  symptoms include muscle atrophy, GI pain, and nausea amongst others  treatment is highly individualized based on cause  Hypoparathyroidism  reduced production of PTH hormone, resulting in excessive calcium deposits in tissue and decreased circulating calcium  treated with calcium replacement therapy with vitamin D (life-threatening is treated with calcium gluconate IV)

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 19 Adrenal Gland Diseases  Cushing Syndrome  increase in adrenal cortex secretion of cortisol  early signs and symptoms include weight gain, hypertension, and emotional instability  other signs and symptoms: fatigue, muscle weakness, change in body fat distribution, moon face, fluid retention, edema, excessive hair growth, fertility changes  treatment depends on cause: surgical removal or radiation of tumor or adrenal gland; drug therapy to suppress ACTH

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 20 Adrenal Gland Diseases (cont’d.)  Addison Disease  partial or complete failure of adrenocortical function  onset usually gradual over weeks to months  fatigue, weakness, gastrointestinal disturbances, weight loss, fluid and electrolyte imbalances, cardiovascular problems, depression, anxiety, “bronzing” of skin tone  treatment includes replacement of natural hormones; increased fluid intake; control of salt and potassium intake; and high carbohydrate/protein diet

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 21  Diabetes Mellitus  little or no insulin production in the pancreas  transport of glucose to cells is impaired  cells begin to use fats and proteins as energy alternative  blood glucose levels continue to increase, resulting in state of hyperglycemia  signs and symptoms include frequent thirst, urination, weight loss, fatigue, increased appetite Endocrine Dysfunction of Pancreas

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 22  Diabetes Mellitus  Type 1: early, abrupt onset before age 30 with little or no insulin secreted  Type 2: more common form with gradual onset after age 30, especially after age 55, with some pancreatic function intact Endocrine Dysfunction of Pancreas (cont’d.)

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 23 Warning Signs and Interventions for Diabetic Coma and Insulin Reaction

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 24  Diabetes mellitus treatment  Goal is to normalize blood glucose levels and minimize complications through: diet control diet control exercise exercise frequent blood and urine testing frequent blood and urine testing insulin injections or oral hypoglycemics insulin injections or oral hypoglycemics weight loss (if overweight) weight loss (if overweight) preventive health care preventive health care Endocrine Dysfunction of Pancreas (cont’d.)

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 25  Gestational diabetes mellitus (GDM)  Type 3: decreased ability to metabolize glucose during pregnancy with onset around weeks of gestation; the condition usually disappears right after delivery.  Treatment might include control of diet; limited intake of simple sugars; oral hypoglycemic agents; insulin Endocrine Dysfunction of Pancreas (cont’d.)

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 26  Hypoglycemia  abnormally low blood glucose level that can be caused by excessive insulin secretion in the pancreas, fasting, or medications  signs and symptoms: sweating, nervousness, hunger, weakness, dizziness, headache, palpitations, confusion, visual disturbances  if severe or untreated, can cause seizures, stupor, coma, and death  Treatment: acute requires intravenous infusion of glucose; hormone glucagon; complex carbohydrate/protein snack with stabilization Endocrine Dysfunction of Pancreas (cont’d.)

Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 27 Precocious Puberty  For boys, puberty that begins before age 9  For girls, puberty that begins before age 8  Causes include tumors of the testes/ovaries, hypothalamic or pituitary dysfunction or tumors, and ingestion of hormones or sex steroids  Treatment depends on cause: no treatment if idiopathic; hormone therapy to suppress sexual maturation until appropriate time; treatment more invasive if cause is testicular or brain tumor