Now, the third type of hormone is our thyroid stimulating hormone or TSH. And the hormone that is released by the hypothalamus that stimulates the release of Tch is known as thyroid releasing hormone. So the hypothalamus releases the thyroid releasing hormone and it travels down the portal veins into this system and that stimulates the release of our thyroid stimulating hormone. Now, TSH, the thyroid stimulating hormone, basically stimulates it causes the thyroid cells in our thyroid to not only increase in number but also increase in size. And this induces, this increases the rate at which those thyroid cells basically produce two important types of hormones known as T three and T four. And we'll discuss what these actually do when we'll look at the thyroid individually.