Parathyroid Gland: What They Are, Function, Location, Levels, Symptoms & Causes

What Is the Parathyroid Gland?

A small, four-lobed endocrine gland behind the thyroid in the neck, the parathyroid gland is an organ whose main function includes the regulation of the calcium levels in the body via the parathyroid hormone. It does perform very vital functions to maintain bone health and proper neuromuscular functioning.

Anatomy of the Parathyroid Gland

Understanding the anatomy of the parathyroid gland is also essential to its function and role in the human body.

Location

The parathyroids are glands in your neck, next to the thyroid.

• Generally found on the posterior surface of the thyroid gland.

• Four parathyroid glands can normally be found in every person.

Structure

• Small, pea-shaped glands.

• Oval or beaked shape.

• Composed of chief cells and oxyphil cells, the cell types that produce the hormones.

Physiology of the Parathyroid Gland

To understand its effect on calcium homeostasis, the physiology of the parathyroid gland has to be appreciated.

Function

• The blood concentration of calcium is maintained within a narrow range.

• The parathyroid hormone is produced and secreted.

• Optimum functioning of bones, muscles, and nerves.

Mechanism of Action

• Actions of PTH on bones, kidneys, and intestines maintain calcium and phosphate concentration.

• PTH causes bone resorption for the release of calcium into the bloodstream.

• Increases kidney calcium reabsorption and intestinal calcium absorption.

Hormones of the Parathyroid Gland

The hormones of the parathyroid gland are mentioned below-

Parathyroid Hormone (PTH)

Parathyroid hormone is another vital hormone released by the parathyroid glands. It also has a primary function in the regulation of calcium.

Synthesis and Secretion

• PTH is synthesised within the chief cells of the parathyroid glands.

• The primary stimulator for PTH secretion is low blood levels of calcium.

Actions of PTH

• Raises blood calcium levels through the promotion of bone resorption.

• Increases absorption by the intestine.

• Lowers excretion by the kidneys.

Disorders of the Parathyroid Gland

Dysfunction of the parathyroid gland can lead to severe medical conditions as PTH plays a critical role in the regulation of bodily calcium levels.

Hyperparathyroidism

Types:

• Primary: Due to a problem within the gland itself.

• Secondary: Due to another condition, such as kidney failure.

• Tertiary: Due to prolonged secondary hyperparathyroidism

Symptoms:

• Weak bones, kidney stones

• Fatigue, depression.

Diagnosis:

• Blood tests (Calcium, PTH levels)

• Imaging studies

Treatment:

• Surgery medications, calcium intake monitoring .

Hypoparathyroidism

Causes:

• Autoimmune diseases

• Surgical removal

• Genetic disorders

Symptoms:

• Muscle cramps, tingling

• Seizures, dry skin

Diagnosis:

• Blood test, low Ca, low PTH level

Treatment:

• Calcium and vitamin D drugs to relieve symptoms.

Treatment of Parathyroid Disorders

The treatment is described below-

Surgical Management

• Parathyroidectomy for primary hyperparathyroidism or adenomas

• Monitoring of calcium levels, and assurance of adequate calcium intake.

Medical Management

• Medications: Calcium supplements and vitamin D analogues

• Lifestyle changes: Balanced diet rich in calcium and regular exercise

Newer Treatments

• Gene therapy might prove to be a future treatment for genetic malfunctions caused by parathyroid disorders

Prevention and Monitoring

Parathyroid disorders can be prevented with a healthy lifestyle, and keeping a check on calcium levels.

• Calcium-rich foods like milk and milk products, green vegetables, nuts, seeds.

• Vitamin D-rich foods like Fatty fish, fortified foods, supplements.

• Blood tests to check for calcium and PTH levels

• Management of any features of calcium imbalance at an early stage.

Parathyroid Gland NEET MCQs (With Answers & Explanations)

Important questions asked in NEET from this topic are:

• Parathyroid gland hormones and their functions

• Disorders related to Parathyroid gland

Practice Questions for NEET

Q1. The blood calcium level is lowered by the deficiency of

1. Thyroxine

2. Calcitonin

3. Parathormone

4. Both 1 and 2

Correct answer: 3) Parathormone

Explanation:

The parathyroid glands secrete a peptide hormone called parathyroid hormone (PTH), which plays a crucial role in regulating calcium levels in the blood. The secretion of PTH is primarily controlled by the circulating levels of calcium ions. When blood calcium levels drop, the parathyroid glands increase the release of PTH to stimulate the release of calcium from bones, increase calcium reabsorption by the kidneys, and promote the activation of vitamin D, which enhances calcium absorption from the intestines. Conversely, when calcium levels rise, the secretion of PTH is reduced, maintaining a balanced calcium concentration in the body.

Hence the correct answer is option 3) Parathormone.

Q2. Tetany is caused by

1. Hyperparathyroidism

2. Hypoparathyroidism

3. Hypothyroidism

4. Hyperthyroidism

Correct answer: 2) Hypoparathyroidism

Explanation:

The clinical complications associated with hypoparathyroidism can result in a disorder termed parathyroid tetany or hypocalcemic tetany, characterized by involuntary muscle contractions that can be distressing and potentially dangerous. Proper diagnosis and management of this condition are essential to restore calcium balance and reduce symptoms.

Hence, the correct answer is option 2) Hypoparathyroidism.

Q3. Which of the following hormones can play a significant role in osteoporosis?

1. Estrogen and Parathyroid hormone

2. Progesterone and Aldosterone

3. Aldosterone and Prolactin

4. Parathyroid hormone and Prolactin

Correct answer: 1) Estrogen and Parathyroid hormone

Explanation:

Estrogen: By preventing bone resorption, or breakdown, this hormone aids in maintaining bone density. Osteoporosis is a disorder in which bones become weak and can be exacerbated by a reduction in estrogen levels, such as occurs after menopause.

Parathyroid hormone (PTH): PTH affects bone metabolism and controls blood calcium levels. Increased bone resorption brought on by high PTH levels can erode bones even more and exacerbate osteoporosis. PTH promotes bone breakdown to release calcium into the bloodstream when blood calcium levels are low.

Hence, the correct answer is option 1)Estrogen and Parathyroid hormone.

Also Read:

• MCQs on Parathyroid Gland

• Mechanism of Hormone Action

• Adrenal Gland

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