NUR 339 Final Exam Study Guide

Endocrine System Disorders Pathophysiology Role of the Hypothalamus • Hypothalamus is main link between neuro and endocrine systems o Responds to nerve stimulation by producing hormones o Nerve fibers run from hypothalamus to pituitary and control release of hormones o Secretes inhibitory and releasing factors which control anterior pituitary hormone release o HPA axis involved in stress response: hypothalamus secretes corticotrophin-releasing factor à anterior pituitary to release corticotrophin àadrenal cortex à cortisol • See Figure 31-1, Porth p. 762 & Table 31-1, Porth p. 763 Feedback mechanisms • Negative Feedback • Most common type • The key is inverse relationships • Increased level of hormone will create a decreased production of the hormone • Decreased level of hormone will create an increased production of the hormone • Example: o Decreased serum calcium level à Increased production of PTH by the parathyroid glands à causes bones to release calcium into blood à increase in serum calcium level • Positive o Rare o When a hormone level is decreased, the gland decreases production of the hormone and vice versa. o Eg: labor and oxytocin Pituitary Gland: • Hormones • Disorders of ADH o Diabetes Insipidus  Due to deficiency or decreased response to ADH à inability to concentrate urine  Excrete large volumes of urine (3-20 L/day)  If thirst mechanism is intact may be able to maintain normal fluid balance  Types: • Neurogenic o Due to defect in synthesis or release of ADH (synthesized in hypothalamus, stored and released by posterior pituitary) o Temporary DI may be caused by head trauma or brain surgery • Nephrogenic o Kidneys unable to respond to ADH o May be due to genetic trait or AE of meds (lithium)  S/S: • polyuria, polydipsia, hypernatremia, dehydration  Treatment: • depends on cause • IV or po fluids • Synthetic vasopressin (Desmopressin, synthetic ADH, DDAVP) o SIADH  S/S: • those of dilutional hyponatremia, CHF, decreased urine output and urine osmolality, decreased BUN and Hct  Treatment: • fluid restriction • diuretics • hypertonic NaCl (3%) solution IV • Growth disorders Thyroid gland • Regulates metabolic rate, growth, & development • Thyroid hormone increases metabolism rate in most body tissues, which increases rate of metabolism of glucose, fat, and protein • TH also effects CV, GI, neuro functioning • Hormones • Calcitonin (peptide) o Calcium regulation – calcium absorption and release by bones • Thyroxine (T4) & Triiodothyronine (T3) o Synthesized in follicular cells and release stimulated by TSH from pituitary which is in turn regulated by thyroxine (T4