The integumentary is the largest system of the body. it's involved 16%of body weight, 1.5 - 2 M square in area. the integumentary system is made up of two parts which are curtaneous membrane (skin) and accessory structure. The curtaneous membrane has two components- outer epidermis (epithelial tissue) and inner dermis (connective tissue).The accessoory structure extend through the epidermis to the skin surface (hair, nails and muscles).

1. Protect body organs and underlying tissue
2. Mantains body temperature (insulation and evaporation/ sweat)
3. Synthesizes vitamin D3 (sun light)
4. Storing of lipids
5. Detect touch, pain, pressure and temperature
6. Excretes salt, water and other organic wastes (glands)

There are two types of skin which are thin skin (most of the body and has four layers of keratinocytes) and thick skin (has five layers of keratinocytes). The five layers of the keratinocytes in thick skin from basal lamina to surface:

• stratum germinativum (fingerprints)
• stratum spinosum
• stratum granulosum
• stratum lucidium (thin skin does not have this strata/layer)
• stratum corneum

1. Pigmentation 

    (carotine)

    carotine is orange-yellow pigment. It can be found in orange vegetables such as carrots and tomatoes.Carotine can be converted to Vitamin A.

    (Melanine)

     Melanine is a yellow-brown or black pigment causing the skin dark color. it's produced in stratum germinativum. skin color depends on melanin production, not on the number of melanocytes.

2. Blood Circulation (Hemoglobin)

    blood circulation takes place in skin color as the blood vessels dilate from heat the skin become redness or when the blood flow decreases the skin become pales looking (cyanosis)