ADRENAL CORTEX FUNCTION&DIS ORDER-1.pptx

ADRENAL CORTEX FUNCTION&DIS ORDER The adrenal gland situated in the upper pool or part of each kidney. There are two parts of the adrenal glands, the adrenal cortex(outer part) and the adrenal medulla (inner part). The adrenal cortex is formed of three layers -Zona glomerulosa -Zona reticul...

ADRENAL CORTEX FUNCTION&DIS ORDER The adrenal gland situated in the upper pool or part of each kidney. There are two parts of the adrenal glands, the adrenal cortex(outer part) and the adrenal medulla (inner part). The adrenal cortex is formed of three layers -Zona glomerulosa -Zona reticular -Zona fasciculata Adrenal Histology  Zona reticular and zona fasciculata produces Cortisol. A hormone that regulates nearly every type of organ and tissue within the body. (such as gluconeogenesis and anti- inflammatory action). Zona glomerulosa produces Aldosterone. It helps to:  Maintain appropriate proportions of water and salts within the body, Na and K regulation in plasma. In addition to intravascular fluid balance.  Action in the kidney: Increase absorption of Na in the distal tubules, and facilitate secretion of K and H. The fine regulation of Na and K by the action of Aldosterone take place in distal tubules.  Aldosterone secretion is controlled by: -Rennin enjotensin system (the main regulation) -Recently ACTH has a miner role in controlling the level Aldosterone. - High level of plasma potassium (hyperkalemia).  High Na and low K---------- =inhibit secretion  Aldosterone: Synthesis in adrenal cortex in zona glomerulosa, its steroid hormone, carries in plasma bound to albumin and to corticosteroid binding globulin (CBG) (60- 70%) and the free Aldosterone is the active form. *Aldosterone is metabolized in the liver and secreted in the urine.  24 hrs urinary Aldosterone secretion, normal range (2 --- 26µg/24hrs.). The half life period of aldosterone is 20- 30minutes. Disorder of Aldosterone Secretion: Hyperaldosteronism (Conn´s Syndrome): In hyperaldosteronism, there is a primary and secondary condition. Primary hyperaldosteronism (Conn´s Syndrome) are conditions in which the adrenal gland releases too much of the hormone aldosterone.  Primary hyperaldosteronism considered a rare condition, but some experts believe that it may be the cause of high blood pressure in some patients. Most cases of primary hyperaldosteronism are caused by: A noncancerous tumor of the adrenal gland (adenoma). The disease is common between the ages of 30 and 50.  -Tumor of adrenal gland (adenoma). -Adrenal hyperplasia -Glucocorticoid receptor defects. Adrenal carcinoma. Secondary hyperaldosteronism: Is generally related to: high blood pressures cirrhosis of the liver. heart failure. nephritic syndrome. Symptoms of hyperaldosteronism include: fatigue, headache, high blood pressure, paralysis, muscle weakness, and numbness. Laboratory Findings : -Hypernatremia -Hypokalemia -Some times hypocalcaemia -Metabolic alkalosis (low K level) Hypoaldosteronism: This usually occur in Addison disease. Destruction of the adrenal cortex by disease e.g. autoimmune disease, tuberculosis-------- cause deficiency in hormones glucocorticoids , androgens and as a result there is low cortisol and low aldosterone.  Isolated Hypoaldosteronism Insufficient aldosterone secretion is seen with: Adrenal gland destruction. following unilateral adrenalectomy. G-layer enzyme deficiencies..  Most hypoaldosteronism occurs in patients with mild renal insufficiency such as persons with diabetes who present with mild metabolic acidosis. high serum potassium, low urinary potassium excretion (urine K less than urine Na).  Glucocorticoids: The most important is cortisol and corticosterol, cortisol represent more than 90% of glucocorticoids. Cortisol: Steroid hormone, 90% of cortisol in plasma is bound to α-globulin corticosteroid binding globulin (CBG), 15% are free cortisol These hormones (glucocorticoids) stimulate out put of glucose by the liver(elevate plasma glucose ) by gluconeogenesis.  Action in lipid and protein is catabolism to provide substrate for glucose synthesis Cortisol is metabolized mainly in the liver and secreted in urine. Plasma R.V 5----25µg/dl. 24hrs urinary excretion 20-----100µg/24 hrs. Cortisol secretion is under control of ACTH from pituitary and ACTH------------RH from hypothalamus.  Disorder of cortisol secretion: 1-Excess cortisol (Cushing’s syndrome): Which may be the result of a tumor of the pituitary glands, adrenal glands or from tumors or cancer arising elsewhere in the body. Cushing’s disease refers to specifically to excessive ACTH secretion by a pituitary tumor.  The cause of Cushing’s syndrome is a pituitary adenoma Cushing’s disease is relatively rare  The symptoms and signs of Cushing’s syndrome are: weight gain in the face, bone and on the back of the neck. Skin changes with easy bruising, Excess hair growth on the face, neck, chest, and abdomen. Generalized weakness and fatigue. loss of muscles, menstrual disorders in women. decreased fertility and/or sex drive. High blood pressure. High blood sugar.  2-Addison’s disease: Is caused by the failure to produce adequate levels of cortisol. This can be caused by a disorder of the adrenal glands. Autoimmune disorder. The disorder causes the body’s immune system to gradually destroy the adrenal cortex. Other causes include certain medications, sepsis, and bleeding into both adrenal gland.  Circadian rhythm of cortisol secretion: The highest level of cortisol occurs between 7-9 a.m and the lowest level occurs between 4: 00---11: 00 p.m. 1-Suspected Cushing syndrome test by using Dexamethazole: Dexamethazole is synthetic glucocorticoids similar in action to cortisol.  At 23:00 hr give 2mg of Dexamethazole and estimate cortisol at 9: 00 hr Suppression is defined as cortisol level