The thyroid gland secretes two main hormones: thyroxine (T4) and triiodothyronine (T3).
Thyroid Hormones Explained
The thyroid gland, a small butterfly-shaped gland located in the neck, plays a crucial role in regulating metabolism. Its primary function is to produce hormones that influence almost every physiological process in the body. The two key hormones produced by the thyroid are:
- Thyroxine (T4): Also known as tetraiodothyronine, T4 is the most abundant hormone secreted by the thyroid. It contains four iodine atoms.
- Triiodothyronine (T3): T3 is the more active hormone and is produced both by the thyroid gland and from the conversion of T4 in other tissues. It contains three iodine atoms.
How Thyroid Hormones Work
These hormones work together to:
- Regulate Metabolism: They control how the body uses energy, which affects weight, heart rate, and temperature.
- Support Growth and Development: Thyroid hormones are essential for proper growth and development, particularly in children.
- Influence Brain Function: They are critical for normal brain development and function throughout life.
- Affect Heart Function: They impact heart rate and the strength of heart contractions.
Production and Regulation
The production of T4 and T3 is regulated by the pituitary gland, which secretes thyroid-stimulating hormone (TSH). When thyroid hormone levels are low, the pituitary releases TSH, which signals the thyroid to produce more T4 and T3. This system ensures that thyroid hormone levels are appropriately balanced.
Table Summary of Thyroid Hormones
| Hormone | Abbreviation | Iodine Atoms | Activity Level | Primary Function |
|---|---|---|---|---|
| Thyroxine | T4 | 4 | Less active | Precursor to T3; main storage form |
| Triiodothyronine | T3 | 3 | More active | Directly influences metabolism and body functions |
Reference: The main hormones produced by the thyroid gland are thyroxine or tetraiodothyronine (T4) and triiodothyronine (T3).05-Jun-2023
