Adrenal Gland- Structure, Hormones, Functions, Disorders

Biology has been interested in the topic of adrenal glands over the years because of their diverse structure, intricate neurological connections, multitude of physiological activities, and large hormone production.

The adrenal glands, also called suprarenal glands, are a pair of glands occurring on the top of kidneys and produce different steroid hormones.Hormones produced by this gland assist in controlling blood pressure, metabolism, immune system, stress response, and other vital processes. The cortex and the medulla, the two components of this gland, are each in charge of manufacturing a distinct hormone.

The two glands on top of the kidneys that are known as the adrenal glands, often referred to as the suprarenal glands, generate distinct steroid hormones.

The adrenal cortex and adrenal medulla are the two unique structures that make up the glands; they have distinctive structures and roles.

Because it is an endocrine gland, the circulation carries the hormones it releases to the appropriate cells or organs.

The small, triangular-shaped glands on top of both kidneys are called adrenal glands, sometimes referred to as suprarenal glands.

Hormones produced by this gland assist in controlling blood pressure, metabolism, immune system, stress response, and other vital processes.

Structure of Adrenal Gland

Located atop each kidney, they are tiny, triangular glands. There are two primary components to every adrenal gland:

• Adrenal Cortex: The outer region, or adrenal cortex, is further subdivided into three zones:
  Mineralocorticoids are produced by the zona glomerulosa.
  Glucocorticoids are produced by the zona fasciculata.
  Hormones are produced by the zona reticularis.

Each zones have its own responsibility to produce specific hormones.

• Adrenal Medulla: The inner area of this gland that produces catecholamines is called the adrenal cortex. The adrenal medulla is located inside the adrenal cortex in the center of it. It produces “stress hormones,” including adrenaline.

Hormones of Adrenal Gland

Your body’s adrenal glands are responsible for the direct release of certain hormones into the bloodstream. Numerous of these hormones are essential to life, and many more have to do with how the body handles stress. The adrenal cortex and adrenal medulla, the two components, have different and unique roles to play.

Certainly! The adrenal glands are small, triangular-shaped glands located above the kidneys. They play a crucial role in regulating various bodily functions. Let’s dive into the hormones produced by these glands:

• Cortisol: Produced by the adrenal cortex, cortisol is a glucocorticoid hormone. It plays several important roles in the body, including regulating metabolism, immune responses, and blood sugar levels1.
• Aldosterone: Also produced by the adrenal cortex, aldosterone is a mineralocorticoid hormone. Its central role is in regulating blood pressure and maintaining electrolyte balance (specifically sodium and potassium) in the body1.
• DHEA (Dehydroepiandrosterone) and Androgenic Steroids: These hormones are also produced by the adrenal cortex. They contribute to sexual development and play a role in maintaining overall health2.
• Epinephrine (Adrenaline) and Norepinephrine (Noradrenaline): These hormones are produced by the adrenal medulla. They are part of the body’s stress response system and help control blood pressure, heart rate, and other activities regulated by the sympathetic nervous system

Functions of Adrenal Glands

• Control of Metabolism: Cortisol facilitates the metabolism of lipids, proteins, and carbohydrates.
• Stress Response: In order to react to stress, catecholamines and cortisol are both essential.
• Electrolyte Balance: Aldosterone controls potassium and sodium levels, which has an impact on blood pressure and fluid equilibrium.
• Development and Reproduction: Androgens have an impact on the processes of sexual maturation and reproduction.

Disorders of Adrenal Glands

Hormonal imbalances are predominantly caused by the overproduction or underproduction of certain hormones by the adrenal glands. The pituitary gland or adrenal glands may be affected by a number of disorders that result in aberrant adrenal function.

• Adrenal Insufficiency

Adrenal insufficiency is a rare disorder. It may be caused by disease of the adrenal glands (primary adrenal insufficiency, Addison’s disease) or by diseases in the hypothalamus or the pituitary (secondary adrenal insufficiency). It is the opposite of Cushing syndrome and is characterized by low levels of adrenal hormones. The symptoms include weight loss, poor appetite, nausea and vomiting, fatigue, darkening of skin (only in primary adrenal insufficiency), abdominal pain, among other.

• Congenital adrenal hyperplasia

Congenital adrenal hyperplasia is a hereditary condition that can potentially cause adrenal insufficiency. In order to create cortisol, aldosterone, or both, a vital enzyme is absent in children with this condition from birth. They frequently experience an overabundance of androgen at the same time, which can cause male traits in girls and premature puberty in boys.

A congenital adrenal hyperplasia diagnosis may take years to come about, depending on how severe the enzyme deficit is. In more serious situations, babies may have vomiting, dehydration, unclear genitalia, and failure to thrive.

• Overactive Adrenal Glands

Adrenal gland nodules that overproduce particular hormones can occasionally form. Suspicion for malignancy is increased by nodules measuring four centimeters or more and by nodules exhibiting specific characteristics on imaging. A functional nodule is one that produces an excess of a certain hormone in both benign and malignant nodules. It is advised to refer patients with functional tumors, malignant tumors, or nodules larger than 4 centimeters for surgical examination.

• Excess of Cortisol: Cushing Syndrome

Overproduction of ACTH due to a benign tumor in the pituitary gland or another tumor in the body can also cause excess cortisol production. We call this Cushing Disease. Excessive and prolonged use of external steroids, such as prednisone or dexamethasone, which are prescribed to treat a variety of inflammatory or autoimmune diseases, including multiple sclerosis, lupus, rheumatoid arthritis, asthma, and inflammatory bowel disease, is another common cause of Cushing syndrome.

• Excess of Adrenaline or Noradrenaline: Pheochromocytoma

A tumor known as a pheochromocytoma causes the adrenal medulla to produce excessive amounts of adrenaline or noradrenaline, which frequently occurs in spurts. Occasionally, an excess of these hormones may arise from neural crest tissue, which has tissue characteristics with the adrenal medulla. We refer to this as a paraganglioma.

Pheochromocytomas can result in intermittent or chronic hypertension that can be challenging to manage with prescription drugs. Headaches, perspiration, tremors, nervousness, and a fast heartbeat are some other symptoms. This kind of tumor is genetically prone to form in some persons.

Frequently Asked Question(FAQ)

Related Article

• Adrenal Gland Structures
• Adrenal Insufficiency