Term
| Structure of Thyroid Gland |
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Definition
| Follicular Cells, Colloids |
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Term
| Synthesis of Thyroid Hormones (thyroglobin) |
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Definition
| glycoprotein is synthesized by follicular cells and secreted by exocytosis into folicle lumen, contains tyrosine residues |
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Term
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Definition
| Ingested Iodine is convereted into iodide (I-) & absorbed. Iodide is transported into follicular cells through secondary active transport mechanism |
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Term
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Definition
| Iodide is oxidized to iodine and attached to tyrosine molecules attached to thyroglobulin. Thyroid peroxidase |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| formed through oxidative condensation b/n MIT & DIT |
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Term
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Definition
| formed through oxidative condensation b/n DIT & DIT |
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Term
| Percentages of iodinated compounds |
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Definition
| 23% MIT, 33% DIT, 7% in T3, 35% in T4 |
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Term
| Release of Thyroid Hormones |
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Definition
| Engulfing part of colloids by follicular cells --> breaking peptide bonds b/n iodinated tyrosine residues & thyroglobulin by proteases in lysosomes -> diffusion of T3 or T4 into circulation |
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Term
| T/F Most of circulating thyroid hormones are bound to plasma proteins. |
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Definition
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Term
| Distribution of transporters for Thyroid Hormones |
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Definition
| T4: 67% globulin, 20% transthyretin, 13% albumin. T3: 46% globulin, 53% with albumin |
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Term
| Plasma concentrations of thyroid hormones |
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Definition
| T4: 8 ug/dl, T3: .15 ug/dl |
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Term
| Where is the thyroid hormone receptor located? |
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Definition
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Term
| What are the three actions of Thyroid Hormone? |
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Definition
| metabolic actions, permissive actions, growth and development. |
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Term
| Permissive action of Thyroid Hormone |
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Definition
| up regulation of B-adrenergic receptors --> (enhancement of the action of Epi & Norepi at normal level --> (anxiety, nervousness, increased HR & CO) |
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Term
| What function does Thyroid Hormone play in development of fetus? |
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Definition
| Formation of nerve terminals, production of synapse, growth of dendrites, formation of myelin. |
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Term
| What happens if a mother has a dietary iodine deficiency during pregnancy? |
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Definition
| Mental retardation of child: cretinism. A result of mother's inability to form thyroid hormone. |
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Term
| Effects of thyroid hormones |
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Definition
| stimulates basal metabolic rate, augment thermogenesis, promote liver gluconeogenesis, and glycogenolysis, increased fatty synthesis by the liver, increased lipolysis in adipose tissue. |
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Term
| Efffect of thyroid on heart |
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Definition
| chronotropic & ionotropic |
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Term
| Effect of thyroid on muscle |
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Definition
| increase protein breakdown |
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Term
| Effect of thyroid hormone on bone |
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Definition
| promote normal growth; increase bone turnover with more bone resorption than bone formation. |
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Term
| Effect of thyroid hormone on GI tract |
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Definition
| increased carbohydrate absorption |
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Term
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Definition
| Increased levels of free T3 and T4: excess thyroid hormone secretion. caused by excess production of TSH. abnormal thyroid stimulator (Graves). Intrinsic disease of thyroid gland. |
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Term
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Definition
| common in young pt (<40yrs). more frequent in female (7-10x). autoimmune disorder. IgG stimulates TSH receptor. |
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Term
| Clinical features of Grave's disease |
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Definition
| Thyrotoxicosis by hyperfunctinal, diffuse enlargment of the thyroid gland. Exaopthalamos: abnormal protrusion of the eyeball. sweating. tachycardia. weight loss. oligomenorrhea. |
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Term
| Clinical Features of Hyperthyroidism |
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Definition
| restlessness, nervousness, emotional lability, sweating, tachydcardia, cardiac palpitation, muscular tremor & muscle weakness, diarrhea with stimulation of the gut, wt. loss, enlarged thyroid: goiter, exophthalmos: bulging eyes |
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Term
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Definition
| Thyroiditis, thyroidectomy, iodine deficiency, secondary hypothyroidism |
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Term
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Definition
| lymphocytic thyroditis (hasimoto's thyroiditis) |
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Term
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Definition
| due to abnormality of in hypothalamus and pituitary gland. (Very Rare) |
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Term
| Signs and Symptoms of hypothryroidism |
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Definition
| growth retardation in children. mental development retardation. myxedema, Sleepy. bradycardia, muscle weakness: mitochondrial impairment, coarse brittle hair, gastric atrophy, constipation, peripheral edema, low T3,T4, high TSH |
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Term
| Diffuse Multinodular Goiter |
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Definition
| Reflects impaired synthesis of thyroid hormone, symmetric enlargement of thyroid gland usually due to deficiency of iodine, common in female, increase in TSH: hypertrophy & hyperplasia of thyroid follicle. coughing and hoarseness secondary to pressure. present in high altitude. |
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Term
| Why do people with diffuse multinodular goiter have high levels of TSH? |
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Definition
| The TSH levels is what causes hypertrophy & hyperplasia of the thyroid follicular cells. |
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Term
| Why do people with Diffuse multinodular goiter experience coughing and hoarsenss? |
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Definition
| It is secondary to the pressure of enlarged thyroid on the larynx or laryngeal nerve. |
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Term
| Chronic lymphocytic thyroiditis |
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Definition
| called hashimoto thyroiditis. most common form of hypothyroitism in U.S.Gradual thyroid failure due to autoimmune destruction of thyroid gland. more common in women than men. significatn genetic effect on the development of the disease. |
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Term
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Definition
| physical trauma, prolonged exposure to cold, infection, shock, decreased oxygen supply, sleep deprivation, pain, exercise, emotional stress. |
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Term
| Hormone response to stress |
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Definition
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Term
| Physiological function of cortisol |
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Definition
| permissive for catecholamines for BP, maintain enzyme level for gluconeogenesis, anti-inflammatory and anti-immune function, normal development of various tissues during fetal and neonatal life. |
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Term
| Effect of increased cortisol during stress |
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Definition
| anti-inflammatory & anti-immune effects. fat metabolism. glucose metabolism. Protein metabolism. CV system. protective effect against damaging influences of stress. inhibition of of nonessential functions (reproduction, growth) |
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Term
| How does cortisol stimulate fat metabolism? |
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Definition
| stimulate lipolysis in adipose tissue, releasing FFA & glycerol. |
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Term
| How does cortisol stimulate glucose metabolism? |
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Definition
| inhibit glucose uptake by muscle, facilitate amino acid uptake by the liver & gluconeogenesis from liver, maintain blood glucose. |
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Term
| Hormones that increase during stress |
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Definition
| Aldosterone, Vasopressin, Growth hormone, glucagon, catecholamine, B endorphin from anterior pituitary gland, decrease in insulin. |
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Term
| Actions of Catecholamine during Stress |
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Definition
| increase hepatic & muscle glycogenolysis, increase breakdown fo TG, diversion of blood from viscera, increased cardiac function, increased ventilation. |
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Term
| What actions does catecholamines do in blood vessels of the viscera and skeletual muscles during stress? |
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Definition
| Vasodilation in skeletal muscles, Vasoconstriction in viscera. |
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Term
| How do catecholamines increase TG breakdown in adipose tissue? |
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Definition
| Glycerol for gluconeogenesis, FFA: oxidation. |
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Term
| How do catecholamines increase ventilatio during stress? |
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Definition
| stimulating brain breathing center, dilating airways. |
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Term
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Definition
| sodium retention, H2O retention, excretion of potassium ion. |
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Term
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Definition
| enhance muscle mass, aiding in the development of secondary sex characteristics |
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Term
| Adrenocortical Hyperfunction |
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Definition
hypercortisolism- hypersecretion of cortisol, cushing's syndrome/disease
Hyperaldosteronism - hypersecretino of aldosterone. Conn's syndrome |
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Term
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Definition
| hypersecretion of aldosterone, Conn's Syndrome |
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Term
| Clinical Feature of Hypercortisolism |
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Definition
| Fat accumulation: face, neck, trunk, abdomen. uncontrolled catabolic effects on bone, muscle & skin. Decrease GI Ca2+ absorption, resulting in low serum Ca2+. inhibit gonadotropin secretion in males and females. |
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Term
| What are some of the uncontrolled catabolic effects on bone, muscle & skin of hypercortisolism? |
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Definition
| Bone resorption: osteoporosis, proximal muscle wasting, skin becoming thinned & easily bruised. -->inhibit fibroblasts, loss of collagen & connective tissue-->thinning of skin-->easy bruising, poor wound healing. |
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Term
| What are the clinical features of hypercortisolism? |
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Definition
| HTN due to enhanced action of catecholamine. Secondary sex characteristics change, glucose intolerance with increased glucose production, hyperinsulinemia, possible immunosuppression due to cortisol's anti-immune effect. |
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Term
| Primary vs. seondary aldosteronism |
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Definition
| primary: adenoma in zona glomerulosa normal renin and high aldosterone. secondary hyperplasia: high renin and high aldosterone |
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Term
| Difference b/n Primary and Secondary Aldosteronism |
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Definition
| Primary Aldosteronism: normal renin, high aldosterone |
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Term
| What are the clinical features of aldosteronism? |
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Definition
| Hypertension due to increase in Na+ and volume expansion, Hypokalemia |
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Term
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Definition
| muscle weakness and fatigue, intracellular K+ is replaced by Na+ & H+. Intracellular movement of H+ causes metabolic alkalosis |
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Term
| Chronic Adrenocortical Insufficiency |
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Definition
| known as addison's disease, uncommon disorder, do not appear until 90% of adrenal cortex has been compromised, commonly caused by autoimmune adrealitis. |
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Term
| What is Acute adrenocortical insufficiency? |
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Definition
| sudden withdrawal of long-term corticosteroid therapy, incrased stress in pt w/ chronic adrenal insufficiency. |
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Term
| Clinical feature of adrenocortical hypofunction |
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Definition
| progressive weakness & fatigue, low BP, loss appetite, significant drop i blood sugar after fasting, GI irritability, increased susceptibility to infection, electrolyte disturbance by mineralocorticoid insufficiency |
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Term
| What are the two tumors of the Adrenal Medulla? |
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Definition
| Neuroblastoma, Phochromocytoma |
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Term
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Definition
| neuroblasts: precursors of normal adrnal medullary cells |
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Term
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Definition
| Cells in the adrenal medulla that secrete epinephrine and norepinephrine. |
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Term
| Clinical Feature of Neuroblastoma |
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Definition
| Neuroblastoma is highly malignant. Neuroblastoma comprises 6-10% of all childhood cancers, peak incidence is in first 3 yrs after birth. enlarged abdomen in young child, palpation of firm, irregular and nontender mass in abdomen, prognosis is generally good. 90% of pts are cured w/ surgical, medical |
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Term
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Definition
| occurs in chromaffin cells of adrenal medulla. benign or malignant occuring in adrenal medulla in adults. rare disease 1:10,000/yr. excessive secretionof epinephrine & norepinephrine by tumor cells, sustained or spisodic HTN w/ palpitation, tachycardia, chest pain, anxiety, hyperglycemia, and clycosuria, prognosis is good w/ surgical Tx. |
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