What Are the Main Layers of Skin and Their Function?

The skin is the largest organ in the body and serves many functions, including acting as a protective barrier, regulating body temperature, storing water and fat, and more. The skin is made up of three main layers such as the epidermis, the dermis, and the subcutaneous fat layer (hypodermis).

The skin is the largest organ in the body. It is soft enough to allow movement, but tough enough to resist easily breaking or tearing. 

The skin serves many functions: 

• Acts as a protective, waterproof shield against heat, light, and injury
• Is our first line of defense against germs such as bacteria 
• Regulates body temperature and cools via sweat
• Stores water and fat
• Is a sensory organ that provides information about pain, pleasure, temperature and pressure
• Prevents water loss
• Helps produce vitamin D when exposed to the sun

The skin varies in texture, thickness, and color from one part of the body to another. For example:

• The skin on the lips and eyelids is thin and delicate, while skin on the soles of the feet is thicker and harder
• The head contains more hair follicles than anywhere else, but the soles of the feet have none

The skin is made up of three main layers: 

• The epidermis
  • The outer layer of skin – this is the skin you can see
  • Protects the more delicate inner layers
  • Consists of three types of cells:
    • Squamous cells make up the stratum corneum, which is the outermost layer of skin that is continuously shed 
    • Basal cells are found just under squamous cells, at the base of the epidermis
    • Melanocytes are also found at the base of the epidermis and make melanin, which gives skin its color
• The dermis
  • The middle layer of the skin
  • Consists of elastic fibers (elastin) for suppleness and protein fibers (collagen) for strength
  • Contains the following:
    • Blood vessels
    • Lymph vessels
    • Hair follicles
    • Sweat glands
    • Collagen bundles
    • Fibroblasts
    • Nerves
    • Sebaceous glands
    • Pain and touch receptors
• The subcutaneous fat layer (hypodermis)
  • The deepest layer of skin
  • Consists of a network of collagen and fat cells
  • Gives smoothness and contour to the body
  • Provides thermal insulation and helps conserve body heat 
  • Acts as a shock absorber to protect the body from injury 
  • Adipose fat stored in the hypodermis is a source of energy