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Adrenal Gland

Last Updated : 13 Jan, 2024
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The right lobes of the liver and the inferior vena cava are located on the front side of the adrenal gland which would be on right.  The right diaphragm crus is attached to the posterior side. The front side of the adrenal gland which would be on left is where the stomach, pancreas, and spleen are located. The left diaphragmatic crus is attached to the posterior aspect.


  • The individual system contains two adrenals, the right of which has a pyramidal shape and the left of which has a semilunar shape, as was mentioned in the introduction.
  • Additionally, the left adrenal gland is noticeably bigger than the right.
  • The glands typically measure 5 by 3 cm and weigh 7 to 10 grammes when combined. The colour of healthy glands is yellowish.
  • Each adrenal gland is encased in a protected bit of fat called a capsule. Although they are not precisely adrenal glands, this capsule layer’s main job is to encapsulate and safeguard each adrenal gland.
Adrenal Gland


Adrenal cortex

Aldosterone, cortisol, and androgen hormones are produced by the adrenal cortex, which is the adrenal gland’s outermost layer. Under a microscope, the three zones that make up the cortex can be seen and clearly distinguished:

The largest and outermost portion of an adrenal gland is called the adrenal cortex. Three distinct zones—the zona glomerulosa, zona fasciculata, and zona reticularis—make up this region. Particular hormones are produced by each zone. Additionally, testosterone production occurs there secondarily. As listed below, the three primary zones or layers that make up the adrenal cortex are each controlled by a different hormone. At the microscopic level, each zone may be identified and discriminated from the others based on structural and anatomical traits, allowing us to fully grasp this anatomic zonation.

Zona glomerusa

Aldosterone, a mineralocorticoid, is mostly produced in the zona glomerulosa, the topmost layer of the body. The renin-angiotensin-aldosterone system is primarily responsible for controlling the production and secretion of aldosterone. Aldosterone synthetase is a particular enzyme that is expressed by the zona glomerulosa layers  Aldosterone plays a significant role in the lengthy treatment of hypertension. DCT  and the collecting duct of something like the kidney are affected by aldosterone, which increases reabsorption of Na and k (by main cells) and h+ ions excretion (by intercalated cells.  The distal colon, as well as sweat glands, react to aldosterone receptor activation by retaining sodium. Although constant ca entering via low-voltage stimulated Ca2+ is necessary for aldosterone synthesis,

Zona fasciculata

The cell lines of the zona fasciculata, which are located seen between glomerulosa and reticularis, produce and produce glucocorticoids like 11-deoxycorticosterone, cortisol levels, and cortisol in people. The anterior pituitary hormone ACTH is the main hormone that induces cortisol output in humans.   It have been demonstrated that neonatal sickness increases the zona fasciculate ability to produce steroids. 
zona reticularis:

(DHEA), DHEA sulphate (DHEA-S), as well as  (the forerunner to testosterone) are indeed the primary androgens that are produced by the zona reticularis, the deepest cortical region in mammals. Additionally, ACTH stimulates DHEAS secretion

  • Mineralocorticoids, such as aldosterone, are released by the zona glomerulosa.
  • Corticosteroids like cortisol are produced by the Zona fasciculata. Secret amounts of androgens are also present .
  • Zona reticularis: This organelle creates dehydroepiandrosterone, or DHES (also called androstenolone)

Adrenal medulla

The medulla is the last and most internal component of the adrenal gland. It has Chromaffin cells, which are the body’s primary source of endorphins and catecholamines (including adrenaline and noradrenaline). In response to stress, these are both stored and released.


  • The Fight or Flight Response, one of the most well-known reactions, is brought on by the adrenal glands’ secretion of stress chemicals.
  • Numerous hormones are produced by the adrenal glands. These hormones are absolutely necessary for the body to function normally. For instance, the glands release cortisol, which supports the immune system and has anti-inflammatory characteristics.
  • Through the production of numerous other hormones, the adrenal gland also assists in controlling blood pressure and metabolism.
  • Catecholamines, or adrenaline-like chemicals like epinephrine and norepinephrine, are produced by the adrenal medulla. 

We’ve all felt that immediate rush of dread and terror whenever something frightening strikes us abruptly and abruptly. We suddenly experience shivers and the urge to flee or rise up and fight. These are the “fight-or-flight” symptoms, and they are brought on by our adrenal glands’ unexpected release of adrenaline. (Indeed, adrenaline is known so because the adrenal gland produces it.) The adrenal medulla generates two distinct hormones, epinephrine and norepinephrine, which could be divided into general terms for adrenaline.

They are in charge of numerous crucial operations, including:

  • metabolism
  • high blood sugar
  • systolic pressure
  • water and electrolyte equilibrium
  • the combination of sex hormones, especially oestrogen and testosterone, throughout pregnancy hormonal changes before and during adolescence stress reaction.

Blood supply

The adrenal glands receive their blood from 3 main components:

  • This lower phrenic artery has a minor branch called the superior adrenal artery.
  • The aorta is the primary origin of the central adrenal artery.
  • This renal artery forms the contralateral source of the lower adrenal artery.

The source of the adrenal artery can vary widely. The aorta,  axis, and, less frequently, an intercostal artery can all be the origin of the superior adrenal artery. There are frequently numerous arteries that makeup one upper adrenal artery. The lower phrenic, renal, upper mesenteric, or celiac axis are all possible origins of the central adrenal artery lower phrenic artery may also be the source of the lower adrenal artery.

The aspect of the glands affects the vein outflow from either the adrenal glands. The left adrenal vein empties through into the left renal vein because the left adrenal gland was physiologically located further out inferior vena cava. The right adrenal vein empties straight through into the inferior vena cava, which is significantly closer to it. There are frequently differences in adrenal venous drainage, especially just on the left side. According to sources, the lower phrenic vein and the left vaginal and adrenal veins link via veins. Additionally frequent are either left adrenal veins.

Hormones of the Adrenal Glands

  • Epinephrine, often known as adrenaline, is a hormone that reacts quickly to stress by speeding up the heartbeat and elevating blood sugar levels.
  • Norepinephrine, also known as noradrenaline, collaborates with epinephrine to help the body respond to stress. Its main job is to get the body and brain ready for action.
  • Hydrocortisone is a steroid hormone also referred to as cortisol. It controls bodily processes like the transformation of lipids and carbohydrates into energy and is crucial for many other metabolic activities.
  • Together with hydrocortisone, corticosterone regulates the immune system and stops inflammatory responses.

Clinical Aspects

  • When the adrenal glands produce insufficient or insufficient amounts of hormones, adrenal gland diseases develop. Certain illnesses can even be brought on by tumours or abnormal growths. High levels of cortisol in the body are a symptom of Cushing’s syndrome. A pituitary or adrenal gland tumour may be the root cause. A malignant tumour called an adrenocortical carcinoma typically appears in the adrenal gland’s outer layer. This kind of tumour is frequently discovered years after it has spread to the body’s other organs.
  • A hereditary condition known as congenital adrenal hyperplasia (CAH) is characterised by extremely low cortisol production. People who suffer from this illness may also have additional hormonal imbalances in which their bodies produce an excessive amount of androgen but very little aldosterone. When the adrenal glands don’t produce enough cortisol or aldosterone, Addison’s Disease develops. Weakness, exhaustion, low blood pressure, nausea, etc. are the results. 70% of the time, Addison’s disease is brought on by an autoimmune illness in which the body unintentionally targets the adrenal glands. As a result, there is insufficient aldosterone production by the adrenal gland.
  • Pheochromocytoma is a tumour that causes the adrenal medulla to produce excessive amounts of adrenaline or noradrenaline, frequently in rushes. Rarely, the excess supply of those same hormones might well be brought on by neural crest tissue, which shares tissue with the adrenal medulla. It is referred to as a paraganglioma.
  • Hypertension brought on by pheochromocytomas may be chronic or sporadic and challenging to manage with usual treatments. Cramps, perspiration, trembling, nervousness, and an accelerated heartbeat are other symptoms. This form of tumour is more likely to grow in some persons due to genetics.
  • Adrenocortical carcinoma is one type of uncommon aggressive adrenal tumour that has progressed towards other body tissues through the time it is discovered. These tumors develop to be many more inches in diameter but have a capacity to develop rather big.
  • Cancerous adrenal tumours may activate and produce too much of 1 or even more hormones, which is followed by the aforementioned symptoms. When the adrenal tumour grows very huge, individuals may develop stomach cramps, abdominal discomfort, or a sensation of stomach heaviness.
  • Excess supply of aldosterone with  1 or both adrenal glands causes hyperaldosteronism. This would be characterised by a rapid heart rate, which frequently necessitates the use of numerous drugs to regulate. Lower serum potassium levels in certain persons can result in muscle pain, fatigue, and cramps. Conn syndrome is the name of the condition where adrenal excess supply is the reason.

Effects of glucocorticoids

  • Exacerbations of asthma that range in severity
  • Exacerbations of the chronic obstructive pulmonary disease that are severe
  • An allergic rhinitis
  • Dermatitis atopy
  • Urticaria/angioedema
  • Anaphylaxis
  • Allergies to drugs and foods
  • Nose growths
  • Pneumonitis with hypersensitivity
  • Sarcoidosis
  • Pneumonia eosinophilia, both acute and chronic
  • Idiopathic pulmonary disease, Pityriasis Vulgaris
  • Severe and sudden contact dermatitis


Adrenal glands release the steroid hormone aldosterone. Aldosterone is classified as a mineralocorticoid since it is the main regulator of the body’s salt and water balance. Additionally, it somewhat affects how proteins, carbs, and lipids are metabolised. Corticosterone, a steroid produced from cholesterol, is used by the body to make aldosterone. The renin-angiotensin system controls aldosterone synthesis in the zona glomerulosa of the adrenal cortex, which occurs in adults at a rate of 20–200 micrograms each day. In reaction to changes in blood pressure, volume, and plasma sodium and potassium levels, the kidneys release renin. Angiotensinogen, a plasma-circulating protein, is broken down into angiotensin I by the action of renin. Angiotensin I is then changed into angiotensin II, which prompts the adrenal glands to release aldosterone. Aldosterone’s biological activity increases salt and water retention while increasing the kidneys’ excretion of potassium (and to a lesser extent by the skin and intestines). It works by attaching to and turning on a receptor in the renal tubular cells’ cytoplasm. Following this, the active receptor prompts the renal tubular cells to produce more ion channels, boosting potassium excretion through the urine and sodium reabsorption into the blood.


Androgens benefit all genders in that they:

  • bone thickness
  • growth of muscle
  • Puberty
  • formation of red blood cells
  • sexual arousal and activity

What function do androgens serve in males?

Androgens support: in those who were born with a male gender preference (AMAB)

  • low voice (vocal cord lengthening)
  • growth of hair on the genitalia, chest, underarms, and scalp
  • development of sperm

What function do androgens serve in women?

Other bodily molecules transform testosterone into estradiol, a type of oestrogen, in people who were designated female at birth (AFAB). It’s a hormone:

  • controls menstruation
  • helps in pregnancy and fertilisation.
  • reduces bone loss (osteoporosis).
  • encourages the growth of pubic and underarm hair.


The body converts the hormone dehydroepiandrosterone (DHEA) into sex hormones for men and women. Thin vaginal tissue is treated with prescription DHEA.

The liver and the adrenal glands both produce DHEA. DHEA levels appear to decrease with age. DHEA levels appear to be decreased in depressed individuals and women postmenopausal.

  • DHEA is frequently prescribed to treat weakening vaginal tissue. 
  • There isn’t enough solid scientific evidence to support many of the claimed claims for DHEA supplements, including treating erectile dysfunction (ED), heart disease, depression, infertility, and ageing skin.
  • Dehydroepiandrosterone, sometimes known as DHEA, is a hormone that your body makes.
  • Some of it is transformed into the main sex hormones for men and women, testosterone and oestrogen.
  • Both the DHEA molecule itself and the actions of testosterone and oestrogen that follow this conversion may contribute to its effects.
  • Some people ponder why DHEA is taken as a supplement given that it is created naturally. The primary cause is the decline in DHEA levels that occurs with ageing and is linked to a number of disorders.

FAQs on Adrenal Gland

Question 1: What symptoms indicate adrenal gland issues?


Typically, a tumour will form and cause issues with the adrenal gland. The synthesis of some crucial hormones may occasionally be affected by tumours, either by accelerating or stopping it.

Question 2: How significant are the adrenal glands?


A number of hormones are released by the adrenal gland into the bloodstream, preparing the body for mobilisation. In addition to cortisol, which is essential for survival, it produces s-e-x hormones.

Question 3: Describe the adrenal glands.


Endocrine glands called adrenal glands are in charge of manufacturing vital hormones needed for metabolic processes and the stress response.

Question 4: What would be determined by the colour of the adrenal gland?


If it would be yellow then it is healthy. If it changes in any colour then it indicates that the adrenal gland is diseased .

Question 5: What are the adrenal glands used for?


The fight-or-flight response is controlled by the adrenal glands, which also regulate blood pressure and help with metabolism.

Question 6: What would happen when the body is under stressful conditions?


Epinephrine would be released from the adrenal gland whenever our body is in stress conditions to cope with the stress.

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