Integumentary
System
Consists of:
Skin, Hair,
& Nails
Skin
• The largest organ in your body. Yes, skin
is an organ.
• Functions of the Skin
– Protective barrier against pathogens
– Prevents water loss
– Offers body protection
– Regulates body temperature through
sweating
3 layers of skin
1. Epidermis: Top layer
– Constantly makes new skin cells to replace
dead ones
– Contains keratin, which as a waterproof
barrier
– Also contains melanin, a brown pigment that
helps protect you from UV rays. (This is why
people tan)
3 layers of skin
2. Dermis: The 2nd layer of skin
– Contains hair follicles (each follicle contains 1
hair)
– Contains the sebaceous glands which
produce an oil called sebum. This lubricates
the skin and hair.
– Contains sweat glands. These release water
and some wastes to cool the body and
maintain homeostasis
3 layers of skin
3. Subcutaneous tissue: The 3rd layer
– Composed of fat cells
– This is used for insulation and an energy
supply
SKIN LAYER DIAGRAM
EPIDERMIS
SEBACEOUS
DERMIS
GLAND
SUBCUTANEOUS
TISSUE
HAIR FOLLICLE
SWEAT GLAND
MICROSCOPE VIEW OF SKIN
LAYERS