The adrenal glands (Figure 22) are paired organs lying on the superior pole of the kidneys. They are often referred to as suprarenal glands. On CT they look like little triangles on an axial image. The adrenal glands are composed of an outer cortex and inner medulla that function as separate glands. The medulla secretes epinephrine and norepinephrine which are stimulants. These stimulants act on many areas of the body including pupil dilatation, bronchodilatation and heart muscle stimulation. The cortex secretes several major hormones including cortisol, corticosterone and aldosterone. As the hormone names indicate, they are steroidal in nature and are components of a group called corticosteroids. Cortisol and corticosterone are used in metabolism of carbohydrates. Aldosterone is essential in mineral balance and water metabolism. Aldosterone acts upon the kidney to increase sodium reabsorption and decrease tubular reabsorption of potassium. It also helps control water balance in the body.
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