Thyroid and Adrenal Glands
Completion requirements
The thyroid and adrenal glands are two essential endocrine organs that regulate a wide range of physiological processes crucial for survival, growth, metabolism, and adaptation to stress.
While the thyroid gland primarily controls the rate of energy metabolism and protein synthesis, the adrenal glands coordinate the body’s stress response, electrolyte balance, and metabolic adjustments through hormonal secretion.
Together, they exemplify how the endocrine system maintains homeostasis through finely tuned hormonal interactions and feedback control mechanisms
1. The Thyroid Gland
1.3. Synthesis and Secretion of Thyroid Hormones
- Iodide trapping by follicular cells.
- Oxidation of iodide to iodine.
- Iodination of tyrosine residues in thyroglobulin → MIT and DIT.
- Coupling by enzymes within the colloid:
- MIT + DIT → T₃
- DIT + DIT → T₄
5.Storage in colloid
until secretion.
6.Proteolysis releases
free T₃ and T₄ into blood (bound to thyroxine-binding globulin) on stimulation
by TSH.
