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Adrenal Gland.pptx
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- 2. Anatomy External environmentalchanges can create scenarios that the human brain interprets as dangerous or stressful. The body can be equipped to face these changes under the influence of the adrenal glands, also known as the suprarenal glands. The left and right suprarenal glands differ slightly in their shape and location on top of their respective kidneys. The right gland is more pyramidal and sits on top of the upper pole of the kidney, while the left gland is more crescenteric and hangs more over the medial side of the left kidney, superior to the hilum.
- 3. The adrenalgland is divided into an outer cortex and an inner medulla The adrenal cortex is subdivided into the zona glomerulosa the zona fasciculata zona reticularis.
- 4. The zonaglomerulosa is comprised of small rounded cells that are responsible for secreting mineralocorticoids such as aldosterone. Aldosterone regulates the uptake of water in the distal convoluted tubules and collecting ducts, which consequently alters the body’s blood pressure. Mainly through increasing the absorption of sodium and chloride back into the blood in exchange for potassium and hydrogen into the urine. The net result of the aldosterone release is to increase blood volume and blood pressure.
- 5. Zona fasciculatais significantly thicker than the other two cortical layers. It is made up of pale staining vacuolated cells arranged in parallel rows. This layer is responsible for secreting glucocorticoids (cortisol and cortisone) to increase the overall blood glucose level in an effort to provide more energy for a system under stress. Result in gluconeogenesis from non sugar sources such as amino acids and lactic acids They also result in increasing the rate at which adipose tissue breaks down triglycerides into fatty acids and glycerol. They also decrease protein synthesis And decrease the effectiveness of our immune system.
- 6. Zona reticularisconsists of smaller cells that stain darker relative to cells of the aforementioned layers. Here, suprarenal androgens are produced, which serve as precursors for testosterone. These represent a small portion of the sex hormones.
- 7. At thecenter of the organ is a thin, grey medulla. Residing here are chromaffin cells, splanchnic nerves and dilated capillaries. The chromaffin cells are responsible for the production of catecholamines, namely epinephrine (adrenaline), norepinephrine (noradrenaline) and dopamine. Epinephrine is released directly into the medullary capillaries and carried to their site of action via systemic circulation. The physiological effect it has is dependent on the neuroreceptors present at the site at which the chemical acts.
- 9. Control of adrenalgland The hypothalamus secretes corticotropin releasing factors which then acts on the anterior pituitary gland to release Adrenocorticotropic hormone (ACTH). ACTH will act on the adrenal cortex to release the required hormone which in turn will exert a negative feedback on the pituitary gland. The adrenal medulla is under the influence of the nervous system.
- 10. Cushing syndrome Pituitary adenomas can result in a hypersecretion of ACTH. The excess ACTH will overstimulate the suprarenal cortex, resulting in hypercortisolism, or Cushing syndrome. The disease is more predominant in women in the young adult age group. Immunosuppression, muscular atrophy, weight gain and hyperglycaemia are some of the clinical manifestations of the disease. Both medical and surgical options can be implemented to correct this disorder.
- 11. Pheochromocytoma Pheochromocytoma(PCC) is the primary neoplasm of the suprarenal medulla. These tumors are rare and may precipitate life threatening hypertension. The neoplasms can also affect extra-adrenal chromaffin tissue. The lesion results in a hyper production of catecholamines, which consequently results in an overactive sympathetic response.