photo.jpg
Transcript
# Chapter 5: Integumentary System ## What does integument mean? - Covering ## Components of Integumentary Skin - Skin - Hair - Nails - Glands ## Did You Know? Skin Facts - Skin weighs 9 lbs (pounds). - Used to determine body fat. ## Functions of Integumentary System 1. Protection: water...
# Chapter 5: Integumentary System ## What does integument mean? - Covering ## Components of Integumentary Skin - Skin - Hair - Nails - Glands ## Did You Know? Skin Facts - Skin weighs 9 lbs (pounds). - Used to determine body fat. ## Functions of Integumentary System 1. Protection: water loss, microbes, UV light. 2. Sensation: hot, cold, pain, pressure. 3. Temperature Regulation: Maintain homeostasis. 4. Excretion: removes waste. 5. Vitamin D Production: UV light stimulates production. ## Epidermis - The 1st major skin region (outside). - Composed of stratified squamous epithelium (several layers of flat, tile-like cells). - **Keratinization**: Process in which cells (with keratin) push old cells to surface. It takes 40-56 days for new cells to reach the surface. ### Stratum Basale (Basal Layer) - Deepest layer of epidermis. - Single layer of cells. - Firmly attached to dermis. - Undergo cell division to produce millions of new cells daily. ### Stratum Spinosum (Spiny Layer) - Superficial to the basal layer. - It appears spiky (Cell shrink, but the desmosomes hold it tight) - Cell division occurs in this layer. ### Stratum Granulosum (Granular Layer) - It is named for abundant granules in its cells. - Some of these contain a waterproofing glycolipid. - That is secreted into the extracellular space. - Contains the subunits of keratin. - The upper border, the cells are beginning to die. ### Stratum Lucidum (Clear Layer) - It is a thin, translucent band of flattened dead keratinocytes. - Thick skin: palm of the hands and soles of the feet. ### Stratum Corneum (Horny Layer) - Outermost layer of epidermis. - 20-30 layers of dead squamous cells filled with keratin. - Accounts for 75% of epidermal thickness. - Dandruff is this layer flaking off scalp.
