Adrenal failure: A condition in which the adrenal glands do not produce enough of the adrenal hormones that control important functions such as blood pressure.
The adrenal glands sit on top of the kidneys. The adrenal is made up of an outer layer (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 mineralocortoids that regulate the levels of minerals such as sodium and potassium in the blood.
The adrenal medulla makes adrenaline (epinephrine) and noradrenaline (norepinephrine). Adrenaline 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. Noradrenaline is a neurohormone, a neurotransmitter, for of most of the so-called sympathetic nervous system.
The term “Addison’s disease” refers to long-term insufficiency of the adrenal cortex. This may be due to a number of different insults to the adrenal including physical trauma, hemorrhage, and tuberculosis of the adrenal, and destruction of the cells in the pituitary gland that secrete ACTH (adrenocorticotropic hormone) which normally drives the adrenal. Addison’s disease is characterized by bronzing of the skin, anemia, weakness, and low blood pressure. The U.S. President John F. Kennedy had Addison’s disease. The condition is named after the British physician Thomas Addison (1793-1860).
- Adrenal gland
Adrenal gland: A small gland located on top of the kidney. The adrenal glands produce hormones that help control heart rate, blood pressure, the way the body uses food, the levels of minerals such as sodium and potassium in the blood, and other functions particularly involved in stress reactions.
- Adrenal medulla
Adrenal medulla: The inner portion of adrenal gland. (The outer portion is the adrenal cortex). 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 […]
Adrenaline: A stress hormone produced within the adrenal gland that quickens the heart beat, strengthens the force of the heart’s contraction, and opens up the bronchioles in the lungs, among other effects. The secretion of adrenaline is part of the human ‘fight or flight’ response to fear, panic, or perceived threat. Also known as epinephrine.
Adrenoleukodystrophy: A rare genetic (inherited) disorder characterized by the breakdown or loss of the myelin sheath surrounding nerve cells in the brain and progressive dysfunction of the adrenal gland. Adrenoleukodystrophy (ALD) is one of a group of genetic disorders called the leukodystrophies that cause damage to the myelin sheath of the nerve fibers in the […]
- Adult ADHD
Attention deficit hyperactivity disorder (ADHD) as found in the adult population. ADHD is a well-known childhood disorder that is characterized by varying degrees of hyperactivity, impulsivity, and/or inattention that lead to difficulty in academic, emotional, and social functioning. Children who are diagnosed with ADHD may continue to exhibit symptoms that persist into adulthood. In the […]