Physiological Functions of the Thyroid Gland

The thyroid gland plays a critical role in regulating the body's metabolism, growth, and development. Located in the front of the neck, this endocrine organ produces hormones essential for numerous physiological functions.

Thyroid Hormones and Their Functions

• Thyroxine (T4) – The primary hormone secreted by the thyroid gland, it regulates metabolic activities.
• Triiodothyronine (T3) – The active form of thyroid hormone, influencing energy utilization and organ function.
• Calcitonin – Regulates calcium metabolism and bone health.

Thyroid Function Regulation

The hypothalamic-pituitary-thyroid axis ensures hormonal balance. The hypothalamus releases thyrotropin-releasing hormone (TRH), stimulating the pituitary gland to produce thyroid-stimulating hormone (TSH), which then prompts the thyroid gland to synthesize T3 and T4.

Thyroid Abnormalities

• Hypothyroidism – Characterized by reduced hormone production, leading to fatigue, weight gain, and depression.
• Hyperthyroidism – Excessive hormone secretion resulting in increased metabolism, rapid heart rate, and weight loss.
• Goiter – Enlargement of the thyroid gland, often due to iodine deficiency.

Assessing Thyroid Function

Thyroid disorders can be diagnosed through various methods:

• Blood tests measuring TSH, T3, and T4 levels
• Ultrasound imaging for structural abnormalities
• Radioactive iodine uptake tests