PC 705 Module 8 Exam - Endocrine and Neurological Disorders

PC 705 Module 8 Exam - Endocrine and Neurological Disorders Hormone release is regulated by: -chemical factors -endocrine factors -neural control Feedback systems provide? -precise monitoring & control of cell environment What is the most common feedback? Negative —a change in chemical, neural, or endocrine response causes a subsequent decrease in synthesis & excretion of the accompanying hormone Which type of hormones can intiate changes in target cells? -free floating hormones The thyroid hormone secretion uses which feedback? Negative Which structures are involved in thyroid hormone secretion? -hypothalamus—releases TRH -anterior pituitary—releases TSH -thyroid gland—releases T3 & T4 (thyroid hormones) TSH binds on what kind of cells on thyroid gland? Receptor on thyroid follicular cells -Causes the release of T3 & T4 (thyroid hormones) TRH release by the hypothalamus increases with? -cold exposure -stress -detection of low T3 & T4 TRH release by the hypothalamus decreases with? Increasing serum thyroid hormones Thyroid hormones need what? Iodide What is the most common thyroid disorder? Primary hypothyroidism What is primary hypothyroidism? -abnormal thyroid gland function -iodide deficiency—common cause worldwide -autoimmune—common cause in US -common in women & elderly Why is iodine deficiency rare in US? -iodized table salt & fortified foods What is the most common autoimmune cause of primary hypothyroidism? -Hashimotos disease -"autoimmune thyroiditis" What is Hashimoto's thyroiditis? -autoimmune destruction of thyroid gland -genetics & epigenetics play a role -thyroid autoantibodies are formed -T cells, NK cells, inflammatory cytokines, and apoptosis of thyroid follicular cells Diagnosis of primary hypothyroidism? -symptoms -low thyroid hormone (T3 & T4) -high TSH (trying to compensate to stimulate the thyroid gland) What is secondary hypothyroidism? -pituitary failure to stimulate the thyroid gland or hypothalamic failure to stimulate the anterior pituitary -can be from a tumor Diagnosis of secondary hypothyroidism? -Symptoms -low TSH -low TH (T3 & T4) The majority of T3 is produced by? Conversion of T4 to T3 in the tissues Clinical manifestations of hypothyroidism? -Lethargy -Weakness -Dry skin -Cold intolerance -Weight gain -Constipation -Coarse brittle hair -Myxedema (edema around eyes, hands, feet) -bradycardia -can have goiter -low BMD (risk for osteoperosis) Severe complication of long term hypothyroidism? Myxedema Coma -hypothermia, bradycardia, hypotension, hypoglycemia, unconsciousness, usually no shivering —medical emergency— Thyroid gland release of thyroid hormones causes what? -iodide uptake & oxidation -increased growth (hypertrophy & hyperplasia of thyroid gland) -decreased apoptosis of thyroid cells What causes a goiter? -inflammation process from autoimmune cell destruction (hypothyroidism) OR -increased thyroid hormone release causes hypertrophy and hyperplasia of thyroid tissue (hyperthyroidism) What is subacute thyroiditis? -uncommon -inflammation of the thyroid gland that usually precedes a viral infection -no antibody involvement like hashimotos or graves -"inflammatory reaction" -fever, tender & enlarged thyroid -can last 2-4 months -initial TH levels increase with stored TH released follow by transient hypothyroidism -can be painless—-"silent thyroiditis" -6-12 months post delivery—- postpartum thyroiditis What is iatrogenic hypothyroidism? -from thyroid ablation, thyroidectomy, & medications (lithium & amiadorone) Thyroid carcinoma? -from exposure to ionizing radiation especially in childhood -tumor growth on thyroid -changes in voice, swallowing issues, difficulty breathing