The adrenal glands are two in number, one right and one left, they are each located near the upper pole of the kidney match. Their average size is 3 inches high, 2 cm wide, 1 cm in thickness, weighs 4 to 6 g, consistency soft buff yellow coloring.
When cut, the adrenals show will consist of two entirely different areas, that difference is reflected in their function. These two areas are:
- the cortex or adrenal cortex, located at the periphery of the gland, the color yellow. It is formed by three layers of glandular cells, these three layers of cells bearing the names of areas glomerular, fascicular and reticular;
- medulla or the adrenal medulla, looking brown-red occupies the center of the gland. It is composed of polygonal cells in cords, stuffed enclaves stain; these enclaves can be highlighted by a special chemical reaction, the chromaffin reaction.
Numerous experiments ablation of adrenal glands in animals performed since Brown-Sequard in 1856 showed that the adrenal cortex is essential to life while the medulla is not.
The removal of the adrenal cortex in animals, as do humans, causes death in 1 to 5 days in a table involving digestive disorders, a cardiovascular collapse and prostration leading to coma. The biological tests show serious disturbances on the equilibrium and metabolism of water and on the balance of electrolytes (sodium and potassium in particular).
The administration of adrenal extracts in adrenalectomized animals corrects these problems.
The cortex secretes many hormones whose chemical composition is now well defined and their manufacture in the adrenal (biosynthesis) and their metabolism in the body. The physiological action of some compounds is however still unknown. (more…)