ZOOL 3214 1st Edition Lecture 3Lecture 3 & 4: The Integumentary SystemI. Overview- Tegue: to cover- 1.5-2m squared (largest organ)- 15% of our body wt. = just skinA. Components- Doctor: dermatologist- Skin- Hair nails- Cutaneous glandsB. Functions- Protection: UV Radiation, pathogens, abrasions, water-loss- Thermoregulation (homeostasis): body temp. Ph, water-balance, secretion- Communication: sensory input/output (ex. Blushing)- Vitamin D synthesisC. Primary Layers1. Epidermis: Cutaneous Layer- Keratinized stratified squamous ep.- Keratin = adds stability to the outer layers- Avascular = does not contain any blood vessels- Epidermal Ridge = makes the skin not smooth & flat (produce finger prints)- Thick & Thin varieties2. Dermis: Cutaneous Layer- Foundation = CT- Deep to the Epidermis- Blood vessels, muscle, nervous tissue, exocrine glands, and hair follicles- Dermal Papillae = interlock w/epidermis ridges- Areolar CT in the Dermal Papillae- Dense Irregular CT: deeper dermis3. Hypodermis: Subcutaneous Layer- Subcutaneous layer = below the skinThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Comprised of adipose CT (fat)- Fascia = binds cutaneous & subcutaneous layers together (clear/white wrapping)-