A person can become easily confused with the functions of the thyroid and parathyroid glands, as they are related to each other; both perform vital functions in the body; both are located in the same region of the neck; both belong to a large family of glands that secrete hormones, the Endocrine System. Past those similarities, the thyroid and parathyroid glands are interdependent of one another, and have distinct functions within the human body.
The thyroid gland is located in the front of the neck, right below the Adam’s apple. It is shaped like a butterfly, consisting of two lobes connected by an isthmus. The control center for the workings of the thyroid gland is another gland called the “hypothalamus”, found above the brain stem. When the hypothalamus sends messages to the thyroid gland, two hormones are secreted: a thyroid releasing hormone (TRH), and a thyroid stimulating hormone (TSH). These hormones bind with iodine to form other hormones called T3 and T4.
The thyroid gland is important for both cellular and brain growth, intelligence, and overall well-being of a person. As hormones are all about keeping bodily processes balanced, a deficiency of these hormones can create a condition called “hypothyroidism”. On the other hand, too much can result its opposite, “hyperthyroidism”. While hypothyroidism has an effect on stunted growth or dwarfism, hyperthyroidism can result in giantism.
A person who suffers from hypothyroidism can experience fatigue, weight gain, feel cold all the time, have dry skin and hair. In addition, they may have slowed thinking and constipation. Women can experience heavy menstrual periods. On the other hand, with hyperthyroidism, a person can be over-stimulated, as in Graves Disease. People with this disease often have a rapid heartbeat, exhibit overt nervousness and irritability. Because they are hyper, they may feel hot and exhausted all the time. This nervousness can result in frequent bowel movements,and women in experiencing shorter or lighter menstrual periods.
Since the thyroid gland is a prime target for tumor growth, both benign and malignant, symptoms of thyroid disease come on gradually, and are often misdiagnosed. The bad news is, a thyroid condition can affect a person’s life for many years, and sometimes a lifetime.
The parathyroid gland differs in structure from the thyroid gland as it consists of 4 separate glands, located right behind the thyroid. Two parathyroid glands are found behind each lobe of the thyroid gland. Whereas the activities of the thyroid are controlled by the hypothalamus and the pituitary gland (both in the brain), the parathyroid is affected mainly by calcium sensing receptors in the gland.
Hormones produced by the parathyroid affect the workings of the gastrointestinal tract, kidneys, deal with bone health and absorption of Vitamin D. The parathyroid controls blood calcium levels by either releasing a hormone that raises serum calcium levels, or lowers them to maintain a constant balance in the body. As with the thyroid gland, too much of PTH (parathyroid hormone) can result in “hyperparathyroidism”, and too little can cause “hypoparathyroidism”.
Having too much PTH can cause loss of energy, osteoporosis, bone pain, insomnia, acid reflux, and kidney stones. Too little of PTH can result in tingling of the fingers, muscle aches/spasms, headaches, mood swings, fatigue/weakness. Diseases of the parathyroid can be treated with supplementation of Vitamin D, or medicines that convert to Vitamin D. Unlike the thyroid gland, there are few malignancies associated with the parathyroid gland.
Differences between the Thyroid and Parathyroid Glands
While the thyroid gland has two or more major blood supplies, the parathyroid is only supplied by a single, major source. Whereas the thyroid is controlled by the hypothalamus and pituitary glands, the parathyroid is controlled by calcium sensors in the gland. The thyroid gland has effect on practically every cell in the body, while the parathyroid is limited to a few discreet tissues. Where malignancies are common in the thyroid, they are not common with the parathyroid.
Both glands can be interdependent when it comes to surgery, as the thyroid can be removed, due to nodules or cancer, and still leave the parathyroid intact. However, the parathyroid can be removed accidentally. These are the similarities and differences between the functions of the thyroid and parathyroid glands.