WARM UP “Tears are the safety valve of the heart when too much pressure is laid upon it.” –Albert Smith 1.Do you agree with this? Why? 2. How does this apply to this unit?

Integumentary System

Overview Integument –Latin for “to cover” –Tough, flexible barrier –Skin

Skin Basics Weighs 4 kg. (9 lbs.) 15 sq. ft. in area

Layers of Skin Epidermis –Thin epithelial tissue –Dead cells Dermis –Many living structures –Connective tissue Hypodermis –Mostly fat

Structures of Skin Sweat glands –99% water Oil glands Hair –Follicles (root) –Live roots, dead tips Sensory receptors Blood vessels

Skin Functions Flexibility –Softness from oils –Dermal c.t. Blocks UV rays –Pigments in epidermis Kills and blocks bacteria, holds moisture –Stratified squamous –Oil glands

Skin Functions Repairs injuries –Cell replacement Makes Vitamin D for calcium absorption –Pigment Temperature regulation –Hairs and fat –Sweat glands Senses –Receptors

WRAP UP List 4 or 5 ways the structure of the skin allows it to help control your body’s temperature.

WARM UP 1.List 4 functions of skin. 2.Identify the structure or structures responsible for each function listed in #1.

WRAP UP Describe why stratified squamous epithelium is effective as a part of the integumentary system (and its functions).