One of a pair of small glands, each of which sits on top of one of the kidneys. The adrenal is made up of an outer wall (the cortex) and an inner portion (the medulla).
The adrenal glands produce hormones that help control the heart rate, blood pressure, the way the body uses food, and other vital functions. The adrenal cortex secretes steroid (cortisone-related) hormones and the mineralocortoids that regulate the levels of minerals such as sodium and potassium in the blood.
The adrenal medulla makes epinephrine (adrenaline) and norepinephrine (noradrenaline). Epinephrine is secreted in response to low blood levels of glucose as well as exercise and stress; it causes the breakdown of the storage product glycogen to the sugar glucose in the liver, facilitates the release of fatty acids from adipose (fat) tissue, causes dilation (widening) of the small arteries within muscle and increases the output of the heart. Norepinephrine secreted by the adrenal gland acts to narrow blood vessels and raise blood pressure.
The name “adrenal” comes from the Latin “ad-“, toward + “rebes”, kidney. It refers to the perch of this gland atop the kidney. The adrenals are also called the suprarenal glands, “supra-” in Latin meaning “on top.”
- Gland, mammary
One of the glands within the breast that secrete milk when prompted to do so by special hormones. Mammary glands are slightly tender to the touch, and may become more so during menstruation or pregnancy. They become enlarged when engorged with milk. See also mastitis.
- Gland, prostate
A gland within the male reproductive system that is located just below the bladder. Chestnut shaped, the prostate surrounds the beginning of the urethra, the canal that empties the bladder. The prostate is actually not one but many glands, 30-50 in number, between which is abundant tissue containing many bundles of smooth muscle. The secretion […]
- Gland, pituitary
The main endocrine gland. It is a small structure in the head and is called the master gland because it produces hormones that control other glands and many body functions including growth. The pituitary consists of the anterior and posterior pituitary. The anterior pituitary is the front portion of the pituitary. Hormones secreted by it […]
- Gland, salivary
One of the glands in the mouth that produce saliva. There are 3 major salivary glands. They are the parotid, submandibular, and sublingual glands. Each of these glands is paired; there is one parotid gland on each side of the head, etc. The parotid glands are located in front of the ears; the submandibular glands […]
- Gland, sudoriferous
The sudoriferous (sweat) glands are small tubular structures situated within and under the skin (in the subcutaneous tissue). They discharge sweat by tiny openings in the surface of the skin. The sweat is a transparent colorless acidic fluid with a peculiar odor. It contains some fatty acids and mineral matter. It is also called perspiration.