Integumentary System Chapter 5

Integumentary System Page 65 Made up of skin & its appendages Hair Nails Sebaceous glands Sweat glands Integumentary means “covering” 3,000 square inches of surface area

Functions of the Skin Page 65 Covering Regulate body temperature Manufacture Vitamin D Nerve receptors Temporary storage of fat, glucose, water & salts Screen out ultraviolet radiation Special absorptive properties A covering – protecting deeper tissues from dehydration, injury, & germ invasion Regulate body temperature – controls the size of the blood vessels in the dermal layer of the skin Manufacture Vitamin D – through absorption of ultraviolet light Nerve receptors – 1 sq. inch contains 72 feet of nerves & hundreds of receptors. Temporary storage of fat, glucose, water & salts Screen out ultraviolet radiation Special absorptive properties – for certain drugs & other chemical substances. We can apply drugs locally for rashes or medication

Structure of the Skin Page 65 Epidermis Dermis Outermost covering Avascular Dermis True skin Connective tissue Vascular Two layers

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Page 65 Epidermal Cells Keratinocytes – comprise most of the epidermis & produce keratin Merkel cells – Sensory receptors for touch Melanocytes – Produce the pigment melanin which protects the skin against the ultraviolet rays of the sun Langerhans cells – Macrophages that defend against microorganisms

Page 67 Epidermal Layers Stratum germinativum – Deepest epidermal layer; undergoes continuous cell division. Papillae originate in this layer (fingerprint). Stratum spinosum – 8-10 cell layers thick Stratum granulosum – Where keratinization occurs Stratum lucidum – Palms & soles Stratum corneum – Dead cell layer Stratum germinativum – it consists of a layer of cells that are mostly keratinocytes. They grow upward & become part of the more superficial layers. Melanocytes & merkel cells are also found in the germinativum layer. Stratum spinosum – melanocytes, kerationocytes, & Langerhans cells. When seen under a microscope this layer looks prickly – thus the name which means little spine. Stratum granulosum – cells begin to die. Keratinzation is the process whereby the keratinization is the process whereby the keratinocyte cells change their shape, lose their nucleus, lose most of their water, & become mainly hard protein or keratin. Stratum lucidum – the cells in this layer appear clear Stratum corneum – composed of dead, flat, scale-like keratinized cells, which slough off daily. Complete cell turnover occurs every 28 to 30 days in young adults, while the same process takes 45 to 50 days in older adults. This layer is also slightly acidic, which helps in the defense against harmful microorganisms.

Skin Color Page 67 Three pigments contribute to skin color: Melanin – produces two distinct classes of melanin Pheomelanin – which is red to yellow Eumelanin – which is dark brown to black Carotene – a yellow to orange pigment found in certain plants. Hemoglobin – pinkish color of some fair-skinned people is due to the presence of oxygen in the hemoglobin Those who have light skin generally have a greater proportion of pheomelanin than those who have dark skin Some drugs bind to melanin & therefore make it easer for people to burn In older adults, melanin collects in spots, often called “aging” or “liver” spots. ***** Tends to accumulate in the stratum corneum. The yellowish tinge of the skin of some Asians is due to variations in melanin as well as to carotene.

Dermis (Corium) Pages 67 – 68 Thicker, inner layer of the skin below the epidermis Composed of: dense connective tissue white blood cells oil & fat glands collagen tissue bands fat cells elastic fibers Many nerve receptors muscle fibers some mast cells Blood vessels & heat regulation Mast cells respond to injury, infection or allergy & produce histamine & heparin

Subcutaneous Layer Page 68 Also called hypodermal layer (Lies under dermis) Not a true part of the integumentary system Attaches integumentary system to the surface muscles underneath Injections given in this area are called hypodermic or subcutaneous.

Page 68 Appendages - Hair Hair is composed of Root shaft, Outer cuticle layer, the Cortex & the Inner medulla. Root = the part of the hair that is implanted in the skin. Shaft = projects from the skin’s surface Hair follicle = an inpocketing of the epidermis where the hair is embedded. The shape determines the curl of the hair. Arrector pili muscle – attached to the hair & when you get chilled your hair stands up. Round follicle = straight hair Oval follicle = wavy hair Flat follicle = curly hair **** Alopecia = baldness

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Appendages - Nails Page 69 Hard structures covering the dorsal surfaces of the last phalanges of the fingers & toes Formed in the nail bed or matrix Lunula: white crescent at the proximal end of the nail

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Appendages – Nails (Cont’d) Page 70 Appendages – Nails (Cont’d) Disease Condition & Nail Color Condition Nail Color liver disease white nails kidney disease half of nail is pink; half is white heart condition nail bed is red lung disease yellow & thickening nails Anemia pale nail bed diabetes yellowish with a slight blush at the base hypoxia bluish nails

Appendages – Sweat Glands Pages 69 – 70 Appendages – Sweat Glands Also called sudoriferous glands Perspiration is 99% water; it is excreted through pores Under the control of the nervous system, these glands may be activated by several factors including heat, pain, fever, & nervousness. 500 ml water lost per day through the skin Ceruminous or wax glands are modified sweat glands & are found in ear canals

Sebaceous Glands Page 70 Secretes sebum which is thick, oily substance Sebum lubricates the skin, keeping it soft & pliable

Page 70 Microorganisms Intact skin is the best way to protect against pathogens Most skin bacteria are associated with hair follicles & sweat glands Handwashing Most effective action to prevent spread of disease 20 seconds for washing hands 2–4 minutes for infectious material If soap & water are not available, use an alcohol-based hand sanitizer that contains at least 60% alcohol. Sanitizers quickly reduce the number of germs on the hands in some situations but do not eliminate all types of germs.

Aging Skin Page 71 SB Becomes more fragile and dry Loss of elasticity Less effective body temperature control Melanocytes decrease Physiological changes can impact self-worth

Disorders of the Skin Pages 70 – 71 Acne vulgaris Common & chronic disorder of sebaceous glands Occurs mostly during adolescence & marked by blackheads, cysts, pimples and scarring Athlete’s foot Contagious fungal infection Blisters between fingers & toes causing cracking & scaling Dermatitis Non-contagious inflammation of the skin

Disorders of the Skin (Cont’d) Page 71 Disorders of the Skin (Cont’d) Eczema Acute or chronic, noncontagious inflammatory skin disease Dry, red, itchy & scaly Impetigo Acute, inflammatory, & contagious skin disease Caused typically by staph or strep Honey crusted exudates

Disorders of the Skin (Cont’d) Page 71 Disorders of the Skin (Cont’d) Psoriasis Chronic inflammatory skin disease (reddish patches covered by silvery-white scales) Autoimmune disease triggered by stress, trauma or infection Ringworm Highly contagious fungal infection Red, circular patches with scaly borders Urticaria (hives) Intensely itchy, red, raised wheals or welts Response to an allergen

Disorders of the Skin (Cont’d) Page 73 Disorders of the Skin (Cont’d) Boils (carbuncles) Painful, bacterial infection of the hair follicles or sebaceous glands May require an incision and drainage Rosacea Common inflammatory disorder (chronic redness and irritation to the face) Triggers include stress, caffeine, hot foods, and alcohol

Disorders of the Skin (Cont’d) Page 73 Disorders of the Skin (Cont’d) Herpes Viral infection that is usually seen as a blister Simplex includes cold sores involving the lips or beneath the nose Genital herpes Virus that may appear as a blister in the genital area; this is covered in Chapter 21 Shingles (herpes zoster) Skin eruption due to a viral infection of the nerve ending Reactivation of the chicken pox virus (varicella)

Disorders of the Hair & Nails Page 73 Disorders of the Hair & Nails Head lice Parasitic insects Intense itching & sores on the head Ingrown nails Common nail problem Fungal infections Infections of the nail Makes up 50% of all nail problems

Disorders of the Hair & Nails (Cont’d) Page 73 Disorders of the Hair & Nails (Cont’d) Warts Viral infections that affect the skin surrounding or underneath the nail Caused by human papilloma virus (HPV)

Pages 73 – 74 Skin Cancer Basal cell carcinoma = Most common & least malignant Squamous cell carcinoma = Most often found on the scalp & lower lip Malignant melanoma = Metastasizes to other areas quickly Change in color, size, shape of a mole Skin & sun exposure

Pages 74 – 76 Burns Rule of nines – measures the percent of the body burned; the body is divided into 11 areas & each area = 9% of the body First-degree burns = Superficial, epidermis only, no blister, redness swelling & pain Second-degree burns = Epidermis & dermis, blister forms Third-degree burns = Complete destruction of epidermis, dermis & subcutaneous layers forming an eschar (black skin)

Page 76 Skin Lesions Abrasion = an injury in which superficial layers of the skin are scraped or rubbed away. Fissure = a groove or crack like break in the skin Laceration = a torn or jagged wound

Pressure ulcer (decubitus ulcers) Page 76 Pressure ulcer (decubitus ulcers) Also known as Bedsores they occur along the spine, coccyx, hips, elbows & heels Preventable & are a primary concern of health care professionals. Stage I – Redness only, skin intact Stage II – Blistered skin, broken or unbroken Stage III – Skin breaks through all layers Stage IV – Ulceration to underlying muscle & bone

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