The Integumentary System Ms. Cohen Anatomy & Physiology

What makes up the Integumentary System? - Skin Nails Hair Glands (variety)

What does this system do for you? Serving as a barrier against infection and injury Helping to regulate body temperature Removing waste products from body Protection against U.V. radiation Producing vitamin D

The layers The skin is composed of two main layers Epidermis Dermis The hypodermis layer composed of fat and connective tissue

Epidermis Many layers of flattened, scaly, mostly dead epithelial cells. Sheds every 14 - 28 days Protein KERATIN replaces cell components in these cells. Keratin is basic structure of hair, nails and calluses. In animals it forms horns, feathers, scales and quills. New cells produced in this layer and pushed upward

Melanocytes located in the _________________________________________ these cells contain the pigment ____________________________ Dark/light skin = same number melanocytes, varying amount melanin Amount of melanin depends on _________________ and ________ Basement cells of epidermis Melanin Heredity and sun exposure

Dermis Two Zones Innermost thick layer Living or Dead? What’s found here? Two zones of the dermis:papillary zone - loose areolar connective tissue containing collagen and fine elastic fibers; connects the epidermis to the thicker and denser reticular zone of the dermis reticular zone - contains dense, irregular and coarse collagen fibers and thick elastic fibers interspersed with fibroblasts, blood vessels and nerves Connective tissueContains blood vessels, nerve endings, glands, sense organs, smooth muscles and hair follicles

Dermis Layer and Thermoregulation Blood vessels narrow to ________________ Blood vessels widen to increase blood flow and ________________ Goosebumps trap heat close to skin. Narrow to conserve heat during cold Widen to increase blood flow and release heat on warm days. Trap heat close to the skin. Question: You appear flush when vessels are narrow or wider?

Sebaceous gland Hair follicle Produce oily secretion called sebum Keeps keratin __________________ Controlled by hormones What type of gland? Mildly toxic to bacteria Can cause _________ Flexible and waterproof Exocrine - secretes sebum into duct (pathway) onto surface acne

Sweat gland What comes out of here? Function? How does it start? Sweat Temperature regulation Nervous system

Hair What types of cuts are these? Hair is produced in dermis by hair follicle Hair is large column of dead cells that have filled with keratin Rapid cell division at hair root causes hair growth Hair gets its color from melanin How long does hair grow for before it falls out?

Nails What do you think cells fill with? ____________ Rapidly dividing cells What do you think cells fill with? ____________ Nail appear pink. Why? ___________ Growth rate =.5 - 1.2 mm per day