THE SKIN OR INTEGUMENTARY SYSTEM
Remember the outer portion of the skin is an example of what type of
tissue?
Epithelia Tissue
FUNCTIONS OF THE SKIN
• PROTECTION• THERMOREGULATION
• CUTANEOUS SENSATION• PRODUCTION OF VITAMIN D
• BLOOD RESERVOIR• EXCRETION
LAYERS OF THE SKIN
EPIDERMIS
DERMIS
HYPODERMIS
EPIDERMIS
• THICK• KERATINIZED
• STRATIFIED SQUAMOUS EPITHELIUM• 4-5 SUBLAYERS
LAYERS OF THE EPIDERMIS
• STRATUM BASALE• STRATUM SPINOSUM
• STRATUM GRANULOSUM• STRATUM LUCIDUM• STRATUM CORNEUM
STRATUM BASALE
• THE DEEPEST EPIDERMAL LAYER• A SINGLE ROW OF LIVING CELLS
• RAPID CELL DIVISION• 10-25% OF THESE CELLS ARE
MELANOCYTES
STRATUM BASALE
STRATUM SPINOSUM
• SEVERAL LAYERS OF LIVING CELLS
• CELL DIVISION IS SLOWER THAN BASALE
STRATUM SPINOSUM
STRATUM GRANULOSUM
• THIN, LIVING LAYER OF CELLS
• KERATINOCYTES WATERPROOF IN THIS LAYER
STRATUM GRANULOSUM
STRATUM LUCIDUM
• DEAD CELLS
• LOCATED ONLY IN THICK SKIN (PALMS OF HANDS & SOLES OF FEET)
STRATUM LUCIDUM
STRATUM CORNEUM
• DEAD CELLS
• SERVES TO PROTECT
STRATUM CORNEUM
THE DERMIS
HAIR FOLLICLES, OIL & SWEAT GLANDS ARE FOUND HERE
EPIDERMIS
DERMIS
HAIR & ITS FUNCTIONS
• WARMTH; IT PREVENTS HEAT LOSS
• DETECT INSECTS ON THE SKIN
• PROTECTION
• FILTER PARTICLES
FACTS ABOUT HAIR
• ABOUT 100,000 IN THE SCALP
• ABOUT 30, 000 IN A MAN’S BEARD
• RATE OF HAIR GROWTH AVERAGES 2 mm/WEEK
• HAIR LOSS AVERAGES 90 HAIRS/DAY
HAIR LOSS• ALOPECIA: HAIR THINNING AND BALDNESS
CAUSES OF HAIR LOSS
• HIGH FEVER• SURGERY
• SEVERE EMOTIONAL TRAUMA• CERTAIN DRUGS
• EXCESSIVE VITAMIN A• CHEMOTHERAPY DRUGS
• RADIATION• GENETICS
MOST IMPORTANT
• POOR NUTRITION (ESPECIALLY LACK OF ENOUGH PROTEIN)
• HORMONAL IMBALANCES