Anatomy and Physiology of Animals/The Skin/Test Yourself Answers

1. The two layers that form the skin are the: epidermis and dermis

2. The special protein deposited in epidermal cells to make them waterproof is keratin

3. Skin structures made of keratin include scales, beaks, claws, nails, hoofs, hairs and feathers.

4. Sweat, sebaceous and mammary glands are all exocrine glands. Meaning they all have ducts through which they expel their products to the outside.

5. The pigment deposited in skin cells that protects underlying skin layers from the harmful effects of the sun is melanin.

6. The skin helps cool an animal down when it is active or in a hot environment by producing sweat and dilating the capillaries in the dermis

7. The skin helps prevent heat loss when an animal is in a cold environment by:
 * a) contraction of the hair erector muscles to make the hairs stand up and trap an insulating layer of air.
 * b) constriction of the capillaries in the dermis to reduce heat loss through the body surface.