Melasma Overview. Patches of melasma are darker than other areas of skin because they have more pigment. The cells that produce pigment in the skin are called melanocytes. Ultraviolet radiation, or UV rays, from the sun stimulate melanocytes to produce pigment.
The human testicle .The two muscles that regulate the temperature of the testes are the dartos andcremaster muscles:â¢ Dartos Muscle The dartos muscle is a layer of smooth muscle fibers in the subcutaneous tissue of thescrotum (surrounding the scrotum).
In order to regulate internal body temperature, the sweat mechanism allows an animal to quickly dissapate heat. Animals like a horse, cow or human will sweat with exercise or in hot temperatures. Reptiles & insects don't sweat as their body temperature is governed by the environmental temperature. Pigs on the other hand, are mammals and need to have water/humidity applied to the skin in order to help dissapate heat.