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Title: Hormone Cascade Pathway Post by: galpinj on Jun 22, 2016 Hi everyone,
I was hoping someone could explain why hormone cascade pathways exist the way they do? For example, why does the hypothalamus release Thyrotropin-Releasing Hormone (TRH) to stimulate the anterior pituitary, which then releases Thyroid-Stimulating Hormone (TSH) to stimulate the Thyroid, which then releases hormones itself. Why doesn't the hypothalamus just stimulate the Thyroid directly?What is the point of the anterior pituitary? Given that the hypothalamus is the organ responsible for linking the nervous system to the endocrine system, it seems reasonable for the hypothalamus to directly stimulate other endocrine glands around the body. I can't understand the reason for relaying all the information first to the anterior pituitary. Any help or input is much appreciated as always! Title: Re: Hormone Cascade Pathway Post by: ryann on Nov 14, 2018 why does the hypothalamus release Thyrotropin-Releasing Hormone (TRH) to stimulate the anterior pituitary, which then releases Thyroid-Stimulating Hormone (TSH) to stimulate the Thyroid, which then releases hormones itself. Why doesn't the hypothalamus just stimulate the Thyroid directly?
Answer: The hypothalamus releases thyroid-releasing hormone (TRH), which stimulates thyrotrophs of the anterior pituitary to secrete TSH. TSH is released by the anterior pituitary and stimulates the thyroid follicular cells to release thyroxine, T4 (80%) and triiodothyronine, or T3 (20%) What is the point of the anterior pituitary? Answer: The anterior pituitary gland secretes six hormones. In this lesson, you will learn the functions of the hormones: growth hormone (GH), prolactin (PRL), follicle-stimulating hormone (FSH), luteinizing hormone (LH), adrenocorticotropic hormone (ACTH), and thyroid-stimulating hormone (TSH). I hope this is helpful |