Integumentary system

In most terrestrial mammals, the scrotum (: scrotums or scrota; possibly from Latin scortum, meaning "hide" or "skin") or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin containing the external spermatic fascia, testicles, epididymides, and vasa deferentia. The scrotum will usually tighten when exposed to cold temperatures.

organ system that protects the body comprising the skin and its appendages (including hair, scales, feathers, hooves, and nails)

small rigid plate that grows out of an animal's skin

thumb|Two urokotori of slightly different sizes A urokotori is a utensil used in Japanese cuisine to remove the scales from the skin of fish before cooking. Although it is possible to remove the scales with a knife, this is more difficult and there is a higher risk of cutting the skin of the fish, especially with small fishes; knife-scaling also risks cutting one's hand.