Glandular disorders

Glands are organs, or collections of cells, which manufacture chemical compounds essential to the body’s functioning. There are two kinds the ductless, or endocrine glands, which release hormones directly into the bloodstream, and the exocrine glands, which release their secretions via ducts or tubes to a particular part of the body, such as the hair, skin, eyes, or alimentary canal.

There are countless exocrine glands throughout the body, from the mucosal glands of the nose to the digestive glands of the alimentary canal and the sweat glands of the sjdn. There are also several larger, complete collections of exocrine glands the salivary glands, the thymus, the pancreas, and the prostate among them. The ones most commonly affected by illness are the salivary glands, for example in mumps, which primarily affects the parotid gland, and the prostate, a gland found at the base of the bladder in men that can become inflamed, particularly in older adults.

There are six main endocrine glands the pituitary, thyroid, parathyroid, pancreas, adrenal, and sex glands (ovaries or testes) and the term glandular disorders refers most commonly to these.

Type I (juvenile) diabetes mellitus is caused by the failure of endocrine cells in the pancreas to produce insulin. The pancreas also produces digestive juices, which pour into the duodenum through the pancreatic duct, but between the groups of cells (acini) that produce the pancreatic juice are groups of hormone-producing cells. The groups of cells are called the islets of Langerhans. Alpha islet cells produce glucagon, which is involved in the breakdown of glycogen and so in raising blood glucose levels. Beta islet cells produce insulin, which is needed for the metabolism of glucose. If insufficient or no insulin is produced, glucose levels rise and the symptoms of diabetes mellitus result.

Pituitary disorders

The activity of several endocrine glands is controlled by the pituitary gland. Specifically, the anterior pituitary gland, stimulated by the hypothalamus, produces trophic hormones that act upon the thyroid gland, adrenal glands, and sex glands. It also produces the growth hormones.
Overproduction of growth hormones may cause gigantism or acromegaly (enlargement and distortion of the bones); underproduction may result in dwarfism, or restricted growth. Excessive secretion of the hormone adrenocorticotropin (ACTH) affects the adrenal glands, causing excessive steroid production. This may cause disorders such as Cushing’s syndrome, which is characterized by abnormal fat deposits, high blood pressure, wasting of the muscles, fullness of the face, and various abnormalities of the body chemistry.

Panhypopituitarism, or overall loss of anterior pituitary function usually the result of a tumor, a cyst, or necrosis of the gland will be followed by failure of all glands under anterior pituitary control. It can be treated by substitution of the various hormones produced by the target glands.
The posterior pituitary gland produces antidiuretic hormone (ADH), which is responsible for maintaining the correct water balance in the body. Deficiency results in diabetes insipidus. This rare disorder is characterized by the production of excessive, extremely dilute urine, with corresponding dehydration and thirst.

The thyroid gland contains cells that produce thyroxine, which collects in follicles between the cells. This microscopic section of thyroid tissue shows normal cells and follicles.

Diabetes

Diabetes mellitus, or sugar diabetes, is the most common endocrine disorder. There are two major types. Type I (juvenile type) is due to deficient insulin production; Type II (Maturity onset) is usually due to insensitivity of the body to normal levels of insulin. Insulin itself is produced by clumps of cells called the islets of Langerhans situated within the pancreas. If they fail to produce insulin, the body cannot make proper use of sugar and starch in the diet. Instead of being used by the body to produce energy, glucose and other sugars accumulate in the blood and are excreted as waste in urine. This is associated with severe thirst and weight loss, while the high blood sugar level encourages infection. If untreated, diabetes can produce a number of other symptoms, such as drowsiness, and can lead eventually to coma and cardiac failure.

Diabetes is a common disorder, affecting some two per cent of the population. All diabetics need treatment to reduce the sugar content of their blood and urine and reduce the risk of associated disorders, such as cataracts or arteriosclerosis. Type II diabetes can sometimes be treated by a special diet or by tablets taken orally. Type I diabetes is usually treated only by daily injections of insulin, combined with a controlled diet.

Overproduction of insulin, in contrast, is quite rare and is caused by an insulinoma, or insulin-producing tumor, of the pancreas.

Goiter is a glandular disorder in which the thyroid gland, situated at the front of the neck, is abnormally enlarged. A goiter may be caused by iodine deficiency or excessive production by the pituitary of thyroid-stimulating hormone (TSH).

Thyroid disorders

The thyroid gland affects the metabolic rate of practically all the body tissues. It is unique among the glands in that it requires iodine obtained from the diet to make its principal hormone, thyroxine, in a process controlled by the pituitary. Healthy thyroid function therefore requires an adequate supply of iodine, a normal pituitary gland, and normal pathways of hormone synthesis and release from the thyroid.

Hyperthyroidism, or excessive production of thyroid hormones, also known as thyrotoxicosis may be caused by a benign tumor (adenoma). More commonly, it is a result of an overactive thyroid. Symptoms include weight loss, flushed skin, thirst, rapid heart rate, tension, and anxiety. Body processes speed up, the thyroid enlarges, and the eyes protrude. Treatment may involve drugs or chemical or surgical irradiation of the thyroid gland.

Hypothyroidism (thyroid deficiency) may develop for a number of reasons, or it may be congenital. Once known as cretinism, the congenital form occurs when a child is born with a deficient thyroid or with no thyroid at all. Or it may develop in adulthood if the pituitary ceases to function normally. Most commonly, the thyroid is attacked by an autoimmune process that slowly destroys the gland and so causes hormone levels to drop, leading to progressive illness. Thyroid deficiency produces a low metabolic rate, giving symptoms such as fatigue, lethargy, depression, slowed speech, which may be slurred, and a changed physical appearance as the skin becomes dry and puffy, and the weight increases. Treatment depends on early diagnosis and involves replacement doses of thyroxine.

Mumps (below) is an infection of the salivary glands, particularly the parotid gland, which causes them to swell. The salivary glands are paired, one of each pair being on either side of the face. All secrete salivary juices into the mouth cavity.