Final answer:
The ST channel refers to the superior thyroid artery and vein that supply the thyroid gland, and it does not enter the gums.
Step-by-step explanation:
The ST channel refers to the superior thyroid artery and vein that supply the thyroid gland. The superior thyroid artery enters the thyroid gland through its superior pole and branches out into smaller arteries that supply blood to different parts of the gland, including the parenchyma, capsules, and stroma. Therefore, the ST channel does not enter the gums, but rather supplies blood to the thyroid gland.