1. Skin Cells Kelsey Howard Period 7

2. Type of Skin Cells Epidermis Dermis Hypodermis

3. What is the epidermis? It is the upper layer of the skin. Made of squamous cells; (flat, scaly cell)

4. About the epidermis Deepest part contains melanocytes –Melanocytes create melanin (skin coloring) Contains five layers –Stratum basale, Stratum spinosum, Stratum granulosum, Stratum licidum, Stratum corneum MELANOCYTES: A pigment-producing cell in the skin, hair and eye that determines their color

5. What is the dermis? The lower middle layer of the skin. Composed of tissues –collagen, elastic tissue, and reticular fibers COLLAGEN: The principal protein in connective tissue, this fibrous, structural molecule provides strength and elasticity to tissue, skin, cartilage, ligaments, tendons and bones RETICULAR FIBERS: Connective tissue fibers

6. About the dermis Contains blood vessels, lymph vessels, hair follicles, and glands –Glands produce sweat and regulates sebum, and body temperature. Made up of two layers –Papillary layers (upper) and reticular layers (lower) Papillary layer contains the thin collagen fibers Reticular layer contains the thick collagen fibers

7. What is the hypodermis/subcutaneous layer? The innermost/thickest layer of skin. Composed of loose connective tissue and adipose cells. Contains major blood vessels of the skin. ADIPOSE CELLS: cells that primarily compose adipose tissue, specialized in storing energy as fat.

8. Structures Epidermis –Keratinocytes Dermis –Nerve endings, sweat glands, oil glands, hair follicles, blood vessels Hypodermis –Fibrous tissue KERATINOCYTES: type of skin cell that makes up 95 percent of the epidermis FIBROUS TISSUE: tissue containing with tight woven strands of collagen protein

9. Functions Epidermis –Cell renewal and preservation of moisture, vitamins, minerals and proteins. Dermis –Removes waste products of metabolism from the epidermis, regulation of body temperature, and skin sensations (touch, pain, heat, cold) Hypodermis –Provides thermal insulation and absorbs fat

10. Osmosis or Diffusion? The body’s skin cells take part in osmosis. Water moves through the dead skin cells in the stratum corneum. Example: When you go swimming in a pool and your skin looks wrinkly. Reasoning: The water moves into the dead skin cells and seeps through the spaces between the dead skin cell flakes, this makes the skin cells rehydrate and swell and expand; creating the wrinkly texture.

11. Cellular Respiration Our skin needs oxygen to stay healthy. We take in oxygen and let out carbon dioxide, this allowing cellular respiration to take place in the body. Cellular respiration is able to take place in the body and while it does oxygen can enter the body through the skin and carbon dioxide can leave the body through the skin.

12. ← dead skin cell skin cell →

13. THE END