integumentary system - ANS-is composed of the skin, hair, oil and sweat glands, nails, and sensory receptors. skin - ANS-also known as the cutaneous membrane, covers the external surface of the body and is the largest organ of the body in weight epidermis - ANS-superficial, thinner portion, which is composed of epithelial tissue, avascular dermis - ANS-deeper, thicker connective tissue portion, vascular hypodermis - ANS-also known as the subcutaneous layer, this layer consists of areolar and adipose tissues functions of integumentary system - ANS-1. Regulates body temperature. 2. Stores blood. 3. Protects body from external environment. 4. Detects cutaneous sensations. 5. Excretes and absorbs substances. 6. Synthesizes vitamin D