© 2009 Delmar, Cengage Learning Anatomy and Physiology Blake Austin College Licensed Vocational Nursing Program Semester 1 Integumentary System

© 2009 Delmar, Cengage Learning Objectives Describe the functions of the skin Describe the structures found in the two skin layers Explain how the skin serves as a channel of excretion Describe the action of the sweat glands Describe some common skin hair and nail disorders Define the key words that relate to this chapter

© 2009 Delmar, Cengage Learning Integumentary System Skin and its appendages –Hair –Nails –Sebaceous glands –Sweat glands Integumentary means covering 3,000 square inches of surface area

© 2009 Delmar, Cengage Learning Functions of Skin Covering Regulate body temperature Manufacture Vitamin D Nerve receptors Temporary storage Screen out ultraviolet radiation Special absorptive properties

© 2009 Delmar, Cengage Learning Structure of the Skin Epidermis –Outermost covering –Avascular Dermis –True skin –Connective tissue –Vascular

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Epidermal Cells Keratinocytes –Comprise most of the epidermis and produce the protein keratin –Keratin renders the skin dry and provides a waterproof covering; it also serves as a barrier against ultraviolet light, bacteria, abrasions and some chemicals Merkel cells –Sensory receptors for touch Melanocytes –Produces the protein melanin which protects the skin against the ultraviolet rays for the sun Langerhans cells –Macrophages that defend against microorganisms

© 2009 Delmar, Cengage Learning Epidermal Layers Stratum germinativum –Deepest epidermal layer and continuously undergoes cell division Stratum spinosum –Cells have slender projections or spiny processes, that connect them with other cells Stratum granulosum –Keratinization begins and the cells begin to die Stratum lucidum –Translucent band of cells found only on the palms of the hand and the soles of the feet Stratum corneum –Outermost or surface region of the epidermis

© 2009 Delmar, Cengage Learning Dermis Also called corium Thicker, inner layer of the skin –Dense connective tissue that is deeper and usually thicker than the epidermis –Contains collagenous and elastic fibers to give strength and elasticity –Hair, nails and certain glands are embedded in the dermis Many nerve receptors –Sensory receptors that detect changes in the environment, such as heat, cold, pain, pressure and touch Blood vessels and heat regulation

© 2009 Delmar, Cengage Learning Subcutaneous Layer Also called hypodermal layer Lies under dermis Not a true part of the integumentary system Attaches integumentary system to the surface muscles underneath

© 2009 Delmar, Cengage Learning Appendages Hair Root shaft Outer cuticle layer Cortex Inner medulla Hair follicle Arrector pili muscle

© 2009 Delmar, Cengage Learning Appendages Nails Hard structures covering the dorsal surfaces of the last phalanges of the fingers and toes Nail bed or matrix –Responsible for nail growth –Produces elongated cells that become keratinized Diseases and nail color

© 2009 Delmar, Cengage Learning Appendages Sweat Glands Also called sudoriferous glands Perspiration 99% water Perspiration is excreted through pores Under the control of the nervous system 500ml water lost per day through skin Ceruminous or wax glands

© 2009 Delmar, Cengage Learning Sebaceous Glands Secrete sebum which is thick, oily substance Sebum lubricates the skin, keeping it soft and pliable

© 2009 Delmar, Cengage Learning Microorganisms Intact skin is the best way to protect itself against pathogens and water loss Most skin bacteria are associated with hair follicles and sweat glands Handwashing –Most effective action to prevent spread of disease 20 seconds for washing hands 2-4 minutes for infectious material

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Aging Becomes more fragile and dry Loss of elasticity Less effective body temperature control Melanocytes decrease Physiological changes can impact self-worth

© 2009 Delmar, Cengage Learning Disorders Skin Acne vulgaris – Common and chronic disorder of sebaceous glands Athlete’s foot – Contagious fungal infection Dermatitis – Inflammation of the skin Eczema – Acute or chronic, noncontagious inflammatory skin disease Impetigo – Acute, inflammatory, and contagious skin disease Psoriasis – Chronic inflammatory skin disease (reddish patches covered by silvery-white scales) Urticaria (hives) – Intensely itching wheals or welts

© 2009 Delmar, Cengage Learning Urticaria

© 2009 Delmar, Cengage Learning Urticaria

© 2009 Delmar, Cengage Learning Disorders Skin Boils (carbuncles) – Painful, bacterial infection of the hair follicles or sebaceous glands Rosacea – Common inflammatory disorder (chronic redness and irritation to the face) Herpes – Viral infection which is usually seen as a blister Genital herpes – Virus which may appear as a blister in the genital area Shingle (herpes zoster) – Skin eruption due to a virus infection of the nerve ending

© 2009 Delmar, Cengage Learning Herpes Simplex

© 2009 Delmar, Cengage Learning Herpes Zoster

© 2009 Delmar, Cengage Learning Disorders Hair and Nails Head lice – Parasitic insects Ingrown nails – Common nail problem where the nail curves downward into the skin due to improper trimming or tight shoes Fungal infections – Infections of the nail Warts – Viral infections that affect the skin surrounding or underneath the nail

© 2009 Delmar, Cengage Learning

Skin Cancer Associated with ultraviolet light and is the most common type of cancer in people –Basal cell carcinoma Most common and least malignant type of skin cancer –Squamous cell carcinoma Grows rapidly and metastasizes to the lymph nodes –Malignant melanoma Occurs in pigmented cells and metastasizes to other areas quickly

© 2009 Delmar, Cengage Learning Skin Cancer

© 2009 Delmar, Cengage Learning Skin Cancer or Toe Fungus?

© 2009 Delmar, Cengage Learning

Burns Rule of nines First degree burns Second degree burns Third degree burns

© 2009 Delmar, Cengage Learning Rule of Nines

© 2009 Delmar, Cengage Learning Skin Lesions Pressure ulcer (decubitus ulcers) –

© 2009 Delmar, Cengage Learning Skin Lesions