Parathyroid Gland for BSC Nursing 1st Year, Structure, Regulation, Role

The parathyroid gland is an important part of the endocrine system. It plays a key role in maintaining calcium balance in the body. Calcium is needed for many body functions. These include muscle contraction, nerve function, and bone strength.

In nursing studies, understanding the parathyroid gland helps in learning about hormonal control and clinical conditions related to calcium imbalance.

Location and Structure of Parathyroid Gland

The parathyroid glands are small endocrine glands present in the neck. They are located behind the thyroid gland.

• There are four parathyroid glands in most individuals

• Each gland is very small, about the size of a grain of rice

• They are soft and oval in shape

• They are embedded in the posterior surface of the thyroid gland

Even though they are small, their function is very important for survival.

Hormone Secreted by Parathyroid Gland

The parathyroid gland secretes a hormone called Parathyroid Hormone (PTH).

• PTH is also called parathormone

• It is produced by chief cells of the gland

• Its main function is to increase blood calcium levels

This hormone works continuously to keep calcium levels within a normal range.

Also Check: BSc Nursing Syllabus, 1st, 2nd, 3rd & 4th Year

Importance of Calcium in the Body

Calcium is an essential mineral. It performs many important functions:

• Helps in bone and teeth formation

• Supports muscle contraction

• Aids in nerve signal transmission

• Plays a role in blood clotting

Because of these functions, the body must maintain a stable calcium level at all times.

Regulation of Blood Calcium Levels

The body maintains calcium balance through a simple control system. This system mainly involves PTH and another hormone called calcitonin.

When Calcium Level is Low (Hypocalcemia)

• The parathyroid gland releases more PTH

• PTH acts to increase calcium in blood

When Calcium Level is High (Hypercalcemia)

• The thyroid gland releases calcitonin

• Calcitonin reduces calcium in blood

This system works through negative feedback. When calcium becomes normal, hormone secretion decreases.

Actions of Parathyroid Hormone (PTH)

PTH acts on three main organs:

• Bone

• Kidney

• Intestine (indirectly)

Each action helps in increasing blood calcium levels.

Action of PTH on Bone

Bone stores a large amount of calcium. PTH helps in releasing this calcium into the blood.

• PTH acts on osteoblasts (bone-forming cells)

• Osteoblasts activate osteoclasts (bone-resorbing cells)

• Osteoclasts break down bone tissue

• This releases calcium and phosphate into the blood

This process increases blood calcium levels.

Action of PTH on Kidney

PTH affects kidney function in two ways:

• It increases calcium reabsorption in distal tubules

• It decreases phosphate reabsorption in proximal tubules

As a result:

• Less calcium is lost in urine

• More phosphate is removed from the body

This helps in maintaining free calcium levels in blood.

Action of PTH on Intestine (Indirect Action)

PTH does not directly act on the intestine. It works through vitamin D.

• PTH activates vitamin D in the kidney

• Active vitamin D increases calcium absorption in the intestine

This process helps in adding more calcium to the blood.

Role of Calcitonin

Calcitonin is another hormone that controls calcium levels. It is secreted by the thyroid gland.

• It is produced by parafollicular (C) cells

• Its main function is to decrease blood calcium levels

Actions of Calcitonin:

• Inhibits osteoclast activity

• Reduces bone resorption

• Increases calcium excretion in urine

Calcitonin acts opposite to PTH. It protects the body from high calcium levels.

Clinical Conditions Related to Parathyroid Gland

Changes in PTH levels can lead to different health conditions that affect calcium balance. 

Hypoparathyroidism

This condition occurs when PTH secretion is low.

Effects:

• Decreased calcium levels (hypocalcemia)

• Muscle cramps

• Tingling in fingers and lips

• Tetany (muscle spasms)

This condition may occur after thyroid surgery if parathyroid glands are damaged.

Hyperparathyroidism

This condition occurs when PTH secretion is high.

Effects:

• Increased calcium levels (hypercalcemia)

• Weak bones

• Kidney stones

• Fatigue and confusion

Long-term high calcium can damage many organs.

Signs of Calcium Imbalance

Changes in calcium levels show clear signs that help in early diagnosis. 

Signs of Low Calcium:

• Tingling sensation in fingers

• Muscle cramps

• Nervous irritability

Signs of High Calcium:

• Weakness

• Nausea

• Increased urination

Early identification of these signs is important in nursing care.

Important Points for BSC Nursing 1st Year Exams

Key facts help in quick revision and better understanding during exams. 

• The parathyroid gland has four small glands behind the thyroid

• It secretes Parathyroid Hormone (PTH)

• PTH increases blood calcium level

• It acts on bone and kidney directly

• It acts on intestine indirectly through vitamin D

• Calcitonin reduces blood calcium level

• PTH and calcitonin work in opposite directions

The parathyroid gland plays a vital role in maintaining calcium balance in the body. Even though it is small in size, its function is very important. PTH ensures that calcium levels remain stable by acting on bone, kidney, and intestine.

Calcitonin helps in lowering calcium when levels are high. Together, these hormones maintain proper calcium balance.

For nursing students, understanding this topic is important. It helps in recognizing symptoms, understanding treatment, and providing proper patient care.

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