Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 50: Anatomy and Physiology of the Integumentary System
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Facts About the Integument Largest organ of the body Maintains homeostasis –Protective –Sensory –Reparative
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Layers of the Skin
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Layers of the Skin (cont.) Epidermis Dermis Hypodermis
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question The outer layer of the epidermis is made up of living cells. A. True B. False
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer B. False Rationale: The outer layer of the epidermis is composed of dead cells called keratinocytes. They have varying degrees of thickness: thinnest over the eyelids and thickest on the palms and the soles of the feet. These cells, although protective in nature, are sloughed continuously.
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Epidermis Outer or surface layer Avascular Formed from the protein keratin Contains melanin Openings for the appendages of the skin: sweat glands, sebaceous glands, hair, and nails
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Functions of the Epidermis Regulates water loss –From openings that secrete sebum Protects underlying structures from UV rays (melanin) Absorbs and scatters radiation (melanin) Protects the underlying structures Protects against microbial invasion
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Dermis Middle layer of the skin Structurally supports the outer layer of skin –Papillary dermis Very vascular connective tissue –Responsive to the SNS
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Which of the following is true of a stage II pressure ulcer, which has eroded into the dermal layer? A. Insensitive to pain B. Lacks hair follicles C. Composed of dead keratinocytes D. Contains infection-fighting cells
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer D. Contains infection-fighting cells Rationale: The dermis contains macrophages, mast cells, T cells, and fibroblasts, all of which help fight foreign invading substances. Hair follicles are imbedded within the dermis. This layer of skin is extremely sensitive to pain, pressure, and heat and cold. The epidermis contains dead keratinocytes.
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Functions of the Dermis BP and temperature regulation –Dilation and constriction in response to heat/cold Sensory nerve endings –Home to receptors for heat/cold, pressure, and pain Immunological functions Reticular dermis –Collagen –Three-dimensional, allowing stretching with movement
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hypodermis Subcutaneous layer under the dermis Connective tissue and fat –Retains heat –Acts as shock absorber –Stores fat calories for future use
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Skin Appendages Sweat glands Sebaceous glands Hair Nails
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Sweat Glands Eccrine sweat glands –Arise from dermis –Transport sweat to epidermis to aid in body temperature Apocrine sweat glands –Less abundant but larger –Secrete “nervous sweat” or body odor
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Sebaceous Glands Secrete sebum Inactive until puberty Lubricates skin and hair Prevents moisture evaporation Conserves body heat
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hair Hair follicle Vascular papilla provides nutrition Melanocytes form color of hair Arrector pili muscles –“Goose bumps” –Prevent heat loss by decreasing surface area
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Structure of the Hair
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question The nails provide the nurse with a “window” into the patient’s circulatory status. A. True B. False
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer A. True Rationale: The nurse can use capillary refill to make a rough determination of circulatory status. If the nail beds blanch but return to their normal color within 3 seconds, this is one of many indictors that circulatory status is intact.
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Nails End product of dead cells Cover the top of the fingers and toes Increase manual dexterity Capillary refill