Skin Structure & Function
The basic structure of skin in cats, dogs and horses is very similar to human skin. Skin is divided into three basic layers.
The uppermost layer is the constantly regenerating thin epidermis, which provides protection from external irritants e.g. pathogens and keeps in nutrients, fluids, salts and water. The species specific differences are seen in the speed of regeneration and thickness of epidermis. Horses have the thickest epidermis of these animals.
The middle layer is called dermis. Blood vessels in dermis supply nutrients to epidermis, as well as participate in regulating body and skin temperature. The nerves are found in hair follicles and in dermis. These sense the pain, temperature and touch.
The inner layer is called subcutis, which functions as reservoir.
Oil and sweat glands are located in dermis. Oil glands secrete fatty acids on the surface of the skin, which provides flexibility on the skin. These fatty acids have different and important role in protecting the skin. Cats and dogs control their temperature by sweating from paws and by panting. Horses sweat across their entire body. The thickness and structure of the skin vary depending on the site e.g. nose, paws, stomach. Significant difference compared to human skin is the pH value, which is acidic in humans pH ~5,5 and in cats, dogs and horses approximately pH 7.
Skin is composed of various cell types of which some are cells of immune system. Skin participates in regulating the immune response. Vitamin D is produced on skin by utilizing sun shine. The skin is a lot more than just a shell of the body and hence the good health of animal’s skin is essential for the well being of the animal.