The adrenal glands are located above the kidneys, at the level of the 8th thoracic vertebra, and have an orange-yellow appearance. The left adrenal gland is semilunar in shape, while the right adrenal gland is conical pyramid-shaped. Each adult adrenal gland measures approximately 4-5 cm in length, 2-3 cm in width, and 0.3-0.6 cm in thickness. Each weighs about 4-5g. The adrenal glands consist of a cortex and a medulla, with the cortex accounting for about 80%-90% of the total weight of the adrenal glands. The cortex is further divided into three layers from the outside in: the outer layer is the zona glomerulosa, accounting for about 15% of the cortex, and primarily secretes salt皮质hormones, mainly aldosterone; the middle layer is the zona fasciculata, accounting for about 78% of the cortex, and primarily secretes glucocorticoids, mainly cortisol; the inner layer is the zona reticularis, accounting for about 9% of the cortex, and secretes sex hormones such as androgens, estrogens, and progesterone. Glucocorticoids are essential for maintaining life, mainly regulating the metabolism of sugar, protein, and fat; salt皮质hormones are mainly responsible for regulating the metabolism of electrolytes such as sodium and potassium; sex hormones mainly promote hair, bone, muscle growth, and the development of secondary sexual characteristics.
The adrenal medulla is almost completely composed of chromaffin cells, brown in color, weighing about 1g, mainly secreting adrenaline and norepinephrine, and its main function is to regulate the metabolism of sugar and fat and strengthen the contraction of the cardiovascular system. The characteristics of adrenal diseases are similar to the excess and deficiency of kidney yang and kidney yin in traditional Chinese medicine, so the treatment of such diseases in traditional Chinese medicine is mainly based on the regulation of yin and yang.