Delineate the many ways the integumentary system protects the body

5. Discuss how the body responds when it is placed under stress from situations such as emergencies or exercise.

What will be an ideal response?

The epidermis has many layers of densely packed cells that are filled with keratin, a waterproof, protective substance that kills the cells. The topmost surface of the skin is composed of waterproof dead cells that are continually being sloughed off, taking bacteria and other pathogens with them. In the deep layers of the epidermis, another type of cell participates in immune responses, providing further protection from pathogens that are able to enter the skin from the outside. Sebaceus glands secrete oil that coats most of the body and its hairs. The pH of the skin ranges from 3 to 5 and is due to acids in the oil. This acidity kills most of the bacteria and other disease-
producing organisms that land on the skin. The skin, then, provides protection from the external environment by being a very effective barrier; not only are the top skin cells hard to penetrate, there are also many ways the skin protects underlying tissues from disease-causing organisms.
The skin also helps with body temperature regulation, or thermoregulation, with both sudoriferous glands and the blood vessels in the dermis. When the body is warm and needs to cool, the sudoriferous glands are stimulated; the evaporation of perspiration takes a great deal of heat away from the body. Blood has a high water content, and water absorbs and transports heat readily. To cool the body, certain blood vessels in the dermis vasodilate. This increases blood flow to the skin, where the heat in the blood can radiate to the environment. This increased blood flow to the skin is what gives the skin its characteristic red color when warm. When the core of the body is cooling, skin blood vessels vasoconstrict so that the warm blood will be shunted to the core to keep it warm.