Endocrine Disorders Flashcards
Which hormones do the anterior pituitary release?
ACTH, TSH, FSH, LH, and GH
Which hormones do the posterior pituitary release?
Oxytocin, ADH
What is ACTH?
Released by anterior pituitary, triggers adrenal glands to release cortisol in response to stressors
What is the function of growth hormone?
Also called somatotropin, stimulates growth/cellular reproduction/cell regeneration
What often results in hypo/hyperfunction of the anterior pituitary glands?
Tumors
What disease is result of the posterior pituitary hyperfunction?
Syndrome of inappropriate antidiuretic hormone secretion (SIADH)
What prompts the posterior pituitary to release ADH?
Osmoreceptors in the hypothalamus–monitor blood solute levels
What clinical consequence results as a result of SIADH?
Hyponatremia–too much water being reabsorbed, osmolarity of extracellular fluid decreases
What disease is a result of posterior pituitary HYPOfunction?
Diabetes insipidus
What are key clinical manifestations of diabetes insipidus?
Polydipsia (frequent drinking), polyuria, hypotonic urine production and hyperosmotic extracellular fluid
What are the two forms of diabetes insipidus?
Neurogenic form (lesions of the hypothalamus or pituitary gland interfere with ADH synthesis transporter) or nephrogenic form (inadequate response to ADH in kidney)
What is the cellular composition of the thyroid?
Follicular cells and parafollicular cells (C cells)
What is the role of follicular cells and parafollicular cells?
Follicular cells secrete iodine CONTAINING thyroid hormone, parafollicular cells secrete calcitonin
What are the two thyroid hormones?
T3 (10%) and T4 (90%)
What is calcitonin?
Hormone involved in calcium/phosphate homestasis, works opposite of PTH and works to decrease calcium levels in the blood
What are the functions of thyroid hormone?
Hormones derived from amino acid TYROSINE (with some iodine added)–circulate bound to plasma proteins, work on target cells to alter expression of genes related to metabolism. Have effect on growth, maturation of tissue, cell metabolism, heat production and oxygen consumption.
What is the feedback loop for thyroid hormone?
Hypothalamus secretes TRH (thyrotropin releasing hormone), stimulates anterior pituitary to release TSH, TSH stimulates thyroid gland follicular cells to produce thyroid hormones
What is Hasimoto’s disease?
Also called chronic lymphocytic thyroiditis. Autoimmune destruction of thyroid gland due to infiltration of autoreactive B and T cells, damages follicular cells
What can result in hypothyroidism?
Hashimoto’s, iodine deficiency, congenital hypothyroidism
What are some of the clinical manifestations of hypothyroidism?
Decreased metabolism–weight gain, difficulty generating body heat, lethargy, goiter, myexedma*
What causes goiter?
Decrease in thyroid hormone results in increased TSH which stimulates thyroid tissue to proliferate in attempt to increase thyroid hormone production
What is myxedema?
Alteration in composition of dermis. Severely advanced hypothyroidism, can result in myxedema coma (in response to infection) which can be fatal. Body’s attempt to compensate for lack of thyroid hormone. Results in puffiness, coarse/sparse hair, periorbital edema, etc.
What is Grave’s disease?
Autoimmune disease that stimulates the thyroid gland. T cells become sensitized to thyroid antigens and stimulate B cells to produce IgG antibodies that bind to TSH receptors= thyroid stimulating immunoglobulins
What is the result of thyroid stimulating immunoglobulins in Graves?
Binding of autoantibodies to follicular cells results in stimulation and synthesis of thyroid hormone independent of TSH. Negative feedback intact, overrun by immunological stimulation.
Why do goiters occur in hyperthyroidism?
Immunological stimulation of thyroid gland, results in hyperproliferation of follicular tissue. With more follicular tissue, causes more thyroid hormone to be released.
What are the types of goiter in hyperthyroidism?
Single nodule or multiple nodules (toxic multinodular goiter) on thyroid gland
What are some clinical manifestations of hyperthyroidism?
Increased metabolic rate, increased heat production, weight loss, goiter, exophthalmos (bulging of eyes), pretibial myexedema, can result in thyroid storm in severe cases