Disorders of the Endocrine Glands Nrsg 407

Function Various glands in body Secretes hormones Transported throughout body

Negative feedback One hormone controls secretion of another Last hormone in the pathway controls secretion of first hormone

Pituitary gland Master gland Controls several organs and hormones Works together with hypothalamus

Pituitary Gland Anterior or Adenohypophysis contains glandular tissue Posterior or Neurohypophysis contains nervous tissue

Anterior Pituitary - Hormones

Posterior Pituitary

Posterior pituitary - SIADH Lack of ADH [aka Syndrome of inappropriate ADH] or diabetes insipidus Vasopressin (pitressin) Act on renal tubules to promote reabsorption of water Vasopressor effect (raise BP) SIADH – Syndrome of inappropriate ADH - The syndrome of inappropriate antidiuretic hormone (ADH) secretion (SIADH) is defined by the hyponatremia and hypo-osmolality resulting from inappropriate, continued secretion or action of the hormone despite normal or increased plasma volume, which results in impaired water excretion.

Thyroid 2 types of cells Parafollicular cells – calcitonin Follicular cells – composed of iodine atoms Thyroxine (T4) Triiodothyronine (T3)

Thyroid cont’d Thyroxine hormone (T4) Regulates body metabolism Thermal regulation Regulation of physical/mental development Thyroxine hormone (T4)

Triiodothyronine (T3) Same as T4 Converted once thyroxine enters cells 1 iodine atom eliminated by enzymes Binds to intracellular receptors in nucleus

Thyrocalcitonin (Calcitonin) Lowers plasma Ca and PO4 Increases Ca deposits in bone Not as important due to parathyroid

Negative feedback mechanism Low serum thyroxine  incr TSH  incr thyroxine  maintain normal BMR

Hypothyroidism Poorly functioning thyroid (primary disease) OR Low secretion of TSH by pituitary gland (secondary cause) Most common: chronic autoimmune thyroiditis – Hashimoto’s disease

Myxedema Fatigue General weakness Muscle cramps Dry skin Bradycardia Cold intolerance

Hyperthyroid Most Common: Graves’ disease (primary) Oversecretion of thyroid Increased body metabolism Tachycardia Anxiety Heat intolerance

Adrenal Cortex Glucocorticoids (Sugar) Sex hormones (Sex) Cortisol Androgens

Adrenal Cortex Mineralcorticoids (Salt) Aldosterone

Mechanism of Control Negative feedback mechanism Glucocorticoids and androgens: Anterior pituitary  release of ACTH  stimulates adrenal  glucocorticoid and androgen

Mechanism of Control Mineralcorticoids: RAAS Hormone: Aldosterone produced Promote sodium reabsorption and potassium excretion

Hypofunction Primary Secondary Destruction by systemic infectious disease Cancer Autoimmune process Secondary Decrease ACTH or hypothalamus disease

Hypofunction Hypoglycemia Fatigue Hypotension Increased skin pigmentation Anorexia Vomiting diarrhea

Hypofunction Chronic primary adrenocortical insufficiency (Addison’s disease) Deficiency of all 3 hormones Rare – usually caused by autoimmune destruction

Acute Adrenocortical Insufficiency Caused when glucocorticoids abruptly withdrawn Provide negative feedback to pituitary to stop secreting ACTH No ACTH  adrenal stops secreting endogenous glucocorticoids Adrenal cortex shrinks (adrenal atrophy)

Symptoms of Adrenal crisis Nausea Vomiting Lethargy Confusion Coma / Shock

Cushing’s Syndrome Primary Secondary Iatrogenic Cortisol-secreting tumors Secondary Pituitary or hypothalamus tumor ACTH secreting tumor Iatrogenic Overdosage of glucocorticoid

Signs/Symptoms Hyperglycemia Protein tissue wasting Bruising Osteoporosis Peptic ulcers Delayed wound healing

Signs/Symptoms Abnormal fat distribution Acne Truncal obesity Striae “Buffalo hump” Moon face Acne Mood/ personality changes

Signs/Symptoms Hypokalemia Na and water retention Decrease inflammatory response