THE ADRENAL GLANDS
Topic: The Endocrine System
Next Unit: Diabetes Mellitus
8 minute read
ADRENAL GLANDS: Adrenal glands (or, suprarenal glands) are the triangular-shaped glands found on top of each kidney that are responsible for the production of adrenalin and other hormones important to the body's normal function. The adrenal glands are divided into the adrenal medulla and adrenal cortex.
The Adrenal Medulla
The adrenal medulla is located in the center of the gland and is responsible for the production and release of epinephrine and norepinephrine.
EPINEPHRINE (ADRENALIN): makes the heart beat faster and squeeze harder, it is also responsible for the psychological feeling of fight or flight. It has many of the same actions as norepinephrine.
NOREPHRINE (NORADRENALIN): responsible for vasoconstriction, wakefulness, glucose release from the liver, and like epinephrine, increasing heart rate and contractility.
The Adrenal Cortex
The adrenal cortex is responsible for regulating water balance, stress response, metabolism, immune response, and sexual function via the production of hormones known as glucocorticoids and mineralocorticoids.
MINERALOCORTICOIDS: The major mineralocorticoid is ALDOSTERONE, which acts on the kidney to regulate blood pressure by modulating the water/salt balance of the urine that is expelled from the kidneys. Increases in aldosterone result in increased salt and water reuptake.
GLUCOCORTICOIDS: The main glucocorticoid is CORTISOL; it is known as the "stress hormone," it prepares the body for both short and long-term disruptions to homeostasis, up-regulates gluconeogenesis (formation of glucose), has anti-inflammatory effects, and stimulates the breakdown of proteins and fats. It also serves an important role in the development of the brain.
- SEX HORMONES: Basic sex hormones, known as ANDROGENS are produced in the cortex and travel to the gonads for further processing. Absence of damage to either the adrenals or the gonads will prevent the proper creation of hormones such as estrogen, testosterone, and progesterone.
Dehydroandrostenedione (DHEA): the most important androgen made in the adrenals and is converted into the other key androgens by the ovaries/testes.
Diseases Associated with the Adrenal Glands
Diseases of the adrenal cortex include
- Addison’s disease and
- Cushing’s syndrome.
ADDISON'S DISEASE: Addison’s disease occurs when the adrenal glands do not produce enough steroid hormones, specifically cortisol and aldosterone. This causes the slow-onset of symptoms such as:
- abdominal pain,
- weight loss and
- darkening of the skin.
A large percentage of people with Addison's disease also have Type I DM and are on insulin. If a person who suffers from Addison's disease suddenly stops taking their prescribed glucocorticoids, or when undiagnosed individuals have an acute Addisonian crisis, left untreated can be fatal.
ADDISONIAN CRISIS SYMPTOMS:
- severe dehydration secondary to diarrhea or vomiting,
- altered mental status,
- hypoglycemia, and
ADDISONIAN CRISIS TREATMENT:
- securing the airway,
- management of blood pressure, and
- rapid transport to definitive care.
CUSHING SYNDROME: Cushing’s syndrome occurs with prolonged exposure to excess levels of cortisol. It may present with:
- high blood pressure,
- abdominal obesity,
- reddish stretch marks,
- round red face ("moon facies"),
- weakened muscles and bones,
- acne, and
- fragile skin.
In the field, treatment of Cushing disease in the field primarily involves
- maintaining the ABCs and
- managing symptoms of cardiovascular disease, as Cushing's confers a high risk of CV disease.