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).
The way in which the hypothalamus controls body temperature is that  it triggers changes to the sweat glands and muscles.The body can  then increase or decrease the amount â¦ of heat that is lost.rain. There is no specific body part that is made for controlling body temperature, and brain controls all the functions of the body, so it also controls the body temperature â¦ . 4 people found this useful.