Lecture Notes

The scrotum is a pouch of skin that holds the two testicles. The skin of the scrotum is more heavily pigmented than the skin elsewhere on the body, and is sparsely covered with hair. The scrotum is divided in the middle by a ridge of skin. The skin of the scrotum varies in appearance under different conditions. For example, when a man is sexually aroused, or when he is cold, the testicles are pulled close to the body. This causes the skin to wrinkle and to become more compact. The changes in the surface of the scrotum help maintain a fairly constant temperature of about 93 degrees Fahrenheit within the testicles. Two sets of muscles control these changes. The dartos muscle is a smooth muscle under the skin that contracts and causes the surface of the skin to wrinkle. The cremaster muscle is within the scrotal sac that causes the testes to elevate.