So these are our hairs that extend to the outside and these are the hair roots. Now, we also have oil glands, also known as sebaceous glands and oil is produced to basically make the hair impermeable to water. We also have these green structures which are the sweat glands. And remember, sweat is another method by which we excrete our waste products to the outside. Sweat is also the method by which we regulate the amount of heat found inside our body. So when we basically want to take the heat and move it to the outside we do it via the process of sweating as we'll see in the next lecture.