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 testes are located outside of the body because the bodies  temperature is too high for the testes and the scrotum has a lower  temperature for them to be able to produce â¦ sperm. + 20 others found this useful. Somya Pal.he temperature needed for the sperms to survive and thrive is lower than the optimum body temperature, hence it is not possible to maintain a lower temperature inside the bo â¦ dy hence the testes are located outside the body.