8.1 Lesson 1: Skin Structure
- The skin and its accessory structures (including hair and nails) make up the integumentary system.
- The integumentary system functions to:
- guard the body’s physical and biochemical integrity
- waterproof, cushion, and protect the deeper tissues
- maintain a constant body temperature
- provide vitamin D synthesis
- provide sensory information about the surrounding environment.
- General Anatomy of Skin:
- an organ composed of all 4 tissue types
- 22 square feet
- 1-2 mm thick
- weight 10 lbs (4.5 kg)
- approx. 28 day cycle.
- The superficial portion of the skin is the epidermis and is composed of epithelial tissue.
- The deeper layer of the skin is the dermis and is primarily composed of connective tissue.
- Deep to the dermis is the subcutaneous layer or hypodermis (not a part of the skin). It consists of:
- adipose tissue
- fat storage
- an area for blood vessel passage
- an area of pressure-sensing nerve endings.
