The control of the thyroid hormone levels in the blood is maintained by the HPT axis. The HPT axis is known as the hypothalamic-piutuitary-thyroid axis and it depends on three things: the hypothalamus, the pituitary, and the thyroid gland. Low levels of thyroid hormone cause the hypothalamus to release TRH, thyrotropin-releasing hormone. This then causes the pituitary to secrete TSH, thyroid-stimulating hormone. This then signals for the thyroid gland to secrete both T3 and T4, which are both types of thyroid hormones. Both T3 and T4 act as a negative feedback loop on both the hypothalamus and the pituitary. This means that a high level of thyroid hormone in the blood will not cause the hypothalamus and pituitary to release TRH and TSH, respectively. The whole system together acts to maintain the balance of thyroid hormone in the blood of an organism.
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Good, but show what HPT stands for before introducing the term "HTP". Maybe add more detail so those who do not know about topic understand
it's a bit confusing
I have trouble understanding what the paragraph is about. The topic sentence is about the HPT axis, but the paragraph mostly focuses on thyroid hormones.
wording
The sentence "The HPT axis is known as the hypothalamic-piutuitary-thyroid axis and it depends on three things: the hypothalamus, the pituitary, and the thyroid gland." can be simplified to "The HPT axis is known as the hypothalamic-piutuitary-thyroid axis which depends on three things: the hypothalamus, the pituitary, and the thyroid gland."