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. So the one thing we have to know about this cycle is our TRH, the thyroid releasing hormone basically affects the entire pituitary in a positive manner. So this is a positive feedback cycle and this is also a positive feedback cycle. That basically means this build up in concentration causes this to build up in concentration and that causes our thyroid to basically increase the concentration of T three and T four.