Structure, Functions and Disorders of Adrenal Gland and Pancreas

Adrenal gland

Structure

In addition to each kidney, two adrenal glands are atop each of them, hence the term suprarenal glands. Generally, the glands are pyramid-shaped, but the exact shape may vary from person to person depending on age and health. In addition to a fibrous capsule, the glands are cushioned by fat that protects them from shocks internally.

Adrenal cortex

Of the adrenal glands' glandular epithelium, the adrenal cortex is the more important part. The glomerulus is separated into three main zones; zona fasciculata, zona glomerulosa, and zona reticularis. An outermost zone of the body consists of an arched, thin layer of columnar cells in the zona glomerulosa. A hormone called aldosterone is produced by the adrenal cortex's zona glomerulosa. In the cortex, there is a zone known as the zona fasciculata, which is the middle and thickest zone. A column of secretory cells surrounds a mass of capillaries. Glucocorticoids are produced in this zone. The zona reticularis consists of polyhedral cells arranged in nests or clumps of the linear or round shape. The region produces mostly glucocorticoids, but some species also make androgens, which are sex steroids.

Adrenal medulla

The adrenal medulla is comprised primarily of the adrenal cortex, while the adrenal medulla accounts for a small proportion of the overall glandular volume. While the adrenal cortex is made of muscle tissue, the adrenal medulla is composed of neural tissue that makes up the sympathetic nervous system during embryonic development. Within blood-filled capillaries and sinusoids, the adrenal medulla is composed of medullary chromaffin cells. Metabolizing catecholamines like norepinephrine, epinephrine, and adrenaline, the medullary chromaffin cells in the adrenal medulla synthesize postganglionic sympathetic cells.

Functions

The adrenal gland produces hormones that are responsible for its functions. The adrenal gland has the following functions:

• In addition to regulating sodium and potassium levels in the blood and other extracellular fluids, mineralocorticoids also help control body temperature.
• The adrenal cortex produces cortisol which regulates metabolism, immunity, and the cardiovascular system.
• During times of stress, the adrenal gland produces hormones that strengthen the body's ability to cope.
• Adrenal glands produce androgens, which are then transformed into sex hormones that support the development of the reproductive system.
• Catecholamines, epinephrine, and norepinephrine, hormones from the adrenal cortex, are involved in the fight-or-flight response.

Disorders

The adrenal gland is associated with the following diseases and disorders;

Cushing's syndrome

Those suffering from Cushing's syndrome have high levels of cortical, the main glucocorticoid hormone produced by the adrenal cortex. An adrenal tumor can produce hypersecretion or the pituitary can produce excessive amounts of ACTH. In this condition, facial, neck, and abdominal adiposity is preceded by an extensive breakdown of tissue proteins. Hyperglycaemia and glycosuria can occur as a result of osteoporosis and increased gluconeogenesis.

Adrenal hypoplasia

As a result of various clinical conditions, adrenal hypoplasia results in the underdevelopment of the adrenal cortex. Primary and secondary adrenal hypoplasia are both possible. Symptoms of primary hypoplasia include underdevelopment of the adrenal gland and hyposecretion of adrenal hormones. The second type of hypoplasia, which only affects the gland's secretions, is less common and less severe.

Addison's disease

Addison's disease results from an under secretion of glucocorticoids and mineralocorticoids which destroys the adrenal gland. Immune cells can produce autoantibodies that attack the cortical cells, causing the disease. Muscle weakness, fatigue, hypoglycaemia, and increased skin pigmentation are all common symptoms of this condition.

Adrenocorticoids adenomas

The cause of cortisol-producing adenomas is increased cAMP levels or protein kinase A expression in the body. While usually benign, these adenomas can sometimes produce different hormones, which can result in hypersecretion. ACTH binds to receptors and releases protein kinase A, which causes adrenal adenomas to form. Cell formation in the cortex is critical for the activity of protein kinase A.

Pancreas

Structure

The pancreas consists of a head, a body, and a tail. Its size is 12-15 cm in length located posterior to the stomach, its head is in the curve of the duodenum. Afterward, its body and head extend laterally to it. There is a splenic connection. With functions that are both exocrine and endocrine, the pancreas is a mixed gland. It secretes digestive enzymes into the pancreatic duct in its capacity as an exocrine gland. Bloodstream is filled with hormones produced by the gland. Endocrine functioning accounts for less than 1% of the weight of a gland. Islet of Langerhans is the name given to this part of the pancreas. A healthy adult pancreas contains 200,000-20,00,000 Langerhans islets.

An area of the pancreas called the Islet of Langerhans contains cells that are involved in hormone production.

Alpha cells - Alpha cells produce the hormone glucagon. When blood sugar levels are low, glucagon is released. This is necessary for controlling blood sugar.

Beta cells - Beta cells secrete insulin. When blood sugar levels are elevated, insulin is released.

Delta cells - Peptide hormone Somatostatin is produced by delta cells. Inhibition of insulin and glucagon is the effect of pancreatic somatostatin.

In addition to the hypothalamus (as GHIH), the stomach and intestines also release somatostatin

F cell (PP cell) - Pancreatic polypeptide hormone is produced by F cells (PP cells).

Functions

Following are the functions of the pancreas:

Exocrine function

It is the exocrine glands of the pancreas that produce trypsin and chymotrypsin, two digestive enzymes. To break down proteins, chymotrypsin and trypsin are present, while amylase and lipase break down carbohydrates and fats, respectively. These pancreatic juices are released into the duct system when the food enters the stomach, culminating in the pancreatic duct.

Endocrine function

Among the endocrine components of the pancreas are the Langerhans islets which secrete glucose and insulin directly into the bloodstream. Insulin and glucagon help control blood sugar levels in the body.

Disorders

Evaluation of pancreatic diseases may be difficult due to the inaccessibility of the pancreas. Pancreatic cancer, pancreatitis, and precancerous conditions affect the pancreas. The symptoms and treatments of each disorder vary.

Pancreatitis

In response to pancreatic enzyme secretion, the pancreas swells and begins to digest. An attack could be painful or it could be chronic.

Precursors to pancreatic cancers

It is unclear what causes pancreatic cancer, although some risk factors increase its likelihood. For example, smoking and genetic cancer syndromes are among the risk factors.

Pancreatic cancer

Adenocarcinomas of the pancreas are one of the most common forms of cancer of the pancreas. Pancreatic duct cells are affected by the tumor, which is a type of exocrine tumor. Approximately 5% of pancreatic tumors arise from endocrine tumors, also known as islets, as well as neuroendocrine tumors.

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