For example, it affects cellular respiration, it affects protein synthesis, and so forth. So we see that an increased concentration of T three and T four hormones in our blood actually increases the rate of cellular respiration, increases the rate at which we produce our ATP by using oxygen. It also increases the rate of protein synthesis and protein degradation. And it also increases the rate at which our heart actually contracts. So it influences this basal metabolic rate. Now, these hormones are actually also very important in the growth and the development of our organism from the child into an adult.