Functions of the skin
Types of barriers
chemical
physical
biological
How much water does a person loose in a day? What is this kind of sweat called
- insensible perspiration
How does the body respond to high or low temperatures?
High: dermal vessels dilate and sweat gland activity increases
Low: Dermal vessels constrict and skin temp drops to slow passive heat loss
Explain cutaneous sensations
Metabolic functions
- chem. conversion of carcinogens and activation of some hormones
Blood reservoir
Excretion
nitrogenous waste and salt
Dimensions of skin
area = 2 m^2 = 22 ft^2 weight = 4.5-5.5 kg = 10-11 lbs thickness = 0.5-4 mm
2 types of skin
thin/ hairy skin
thick/hairless skin
-palms and soles of hands, feet, and digits
3 layers of skin
Epidermis
-keratinized, stratified, squamous epithelium
Dermis
-areolar and dense irregular connective tissue
Subcutaneous/hypodermis layer
4 types of cells in epidermis
Stratum Basale
Stratum Spinosum
Stratum Granulosum
Stratum lucidum
- thin, clear band of 2-3 rows of flat, dead keratinocytes
Stratum Corneum
Outer dermal layer
Deeper dermal layer
3 sensory structures in the deep dermal layer
Striae
- appear if skin is stretched too much and the dermis breaks
Lines of cleavage
Epidermal ridges
Dermatoglyphics
study of epidermal ridges