The Integumentary System

10/1/2016

• Organ system that protects the body from various kinds of damage • Examples: water loss, abrasion • Includes skin and its derivatives • Hair • Nails The Integumentary System • Glands • Sebaceous • Sudoriferous • Ceruminous • Scales, feathers, hooves in other animals

Structure of the Skin

Hair shaft • One of the body’s largest organs Dermal papillae • 2 main layers Epidermis Subpapillary Papillary vascular plexus • Epidermis layer Pore • Dermis Appendages of skin Dermis Reticular • Eccrine sweat layer gland • Arrector pili muscle Hypodermis • Sebaceous (superficial fascia) (oil) gland • Hair follicle Nervous structures • Hair root • Sensory nerve fiber Cutaneous vascular • Pacinian corpuscle plexus • Hair follicle receptor Adipose tissue (root hair plexus)

Structure of the Skin

Hair shaft • Epidermis Dermal papillae • 4-5 main layers Epidermis Subpapillary vascular plexus • Stratum corneum Papillary layer Pore • Surface layer, dead cells Appendages Keratin of skin • Dermis • Stratum germinativum Reticular • Eccrine sweat layer gland • Dividing cells • Arrector pili • Melanin muscle Hypodermis • Sebaceous (superficial fascia) (oil) gland • Hair follicle Nervous structures • Hair root • Sensory nerve fiber Cutaneous vascular • Pacinian corpuscle plexus • Hair follicle receptor Adipose tissue (root hair plexus)

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Structure of the Skin

Hair shaft • Dermis Dermal papillae • Deep to epidermis Epidermis Subpapillary vascular plexus • Contains Papillary layer Pore • Connective tissue Appendages of skin • Nerve endings Dermis Reticular • Eccrine sweat • Blood vessels layer gland • Hair follicles • Arrector pili muscle • Skin glands Hypodermis • Sebaceous Hypodermis (superficial fascia) (oil) gland • • Hair follicle Nervous structures • Hair root • Sensory nerve fiber Cutaneous vascular • Pacinian corpuscle plexus • Hair follicle receptor Adipose tissue (root hair plexus)

Structure of the Skin Structure of the Skin

• Epidermis and dermis are attached to each other with varying • Epidermal derivatives degrees of strength • Hair • Structure • Root • Shaft • Follicle • Pigments • Melanin = ranges of colors = yellow/red, brown, black • Gray = lack of pigment • Carotene = yellowish

Structure of the Skin

Hair shaft Epidermal derivatives Dermal papillae • Epidermis Subpapillary • Hair cont. Papillary vascular plexus layer Pore • Functions Appendages • Insulation Dermis of skin Reticular • Eccrine sweat • Protection layer gland • Arrector pili • Sensation muscle Hypodermis • Sebaceous • Psychosocial (superficial fascia) (oil) gland • Hair follicle • Nails Nervous structures • Hair root • Sensory nerve fiber Cutaneous vascular • Pacinian corpuscle plexus • Hair follicle receptor Adipose tissue (root hair plexus)

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Structure of the Skin Structure of the Skin

• Epidermal derivatives • Epidermal derivatives • Glands • Glands • Sebaceous • Sudoriferous • Associated with hair follicles • Tubular glands, numerous on palms and soles • Secrete oil • Secrete sweat • Fats, cholesterol, proteins, salts • Water, salts, urea, uric acid, amino acids, lactic • Functions acid, ascorbic acid • Functions

Structure of the Skin Functions of the Skin

• Epidermal derivatives • Sensation • Glands • Protection • Ceruminous • Chemical, physical/mechanical, biological • Secrete ear wax • Excretion • Modified sweat glands • Vitamin D production • Functions • Temperature regulation

Control Center Information sent (thermoregulatory Information sent along the afferent center in brain) along the efferent Skin Disorders pathway to control pathway to center Afferent Efferent effectors pathway pathway Receptors • Color can be an important indicator of health Temperature-sensitive Effectors cells in skin and brain Sweat glands • Pigmentation Sweat glands activated Response • Paleness/redness Evaporation of sweat Stimulus Body temperature falls; • Cyanosis Body temperature stimulus ends BALANCE rises • Jaundice Stimulus Response Body temperature falls Body temperature rises; stimulus ends

Receptors Effectors Temperature-sensitive Skeletal muscles cells in skin and brain

Efferent Afferent Shivering pathway pathway begins Information sent Information sent along the efferent along the afferent pathway to effectors Control Center pathway to control (thermoregulatory center center in brain)

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Skin Diseases Acne • Acne • Impetigo • Psoriasis • Decubitus ulcers • Sunburn • Skin cancer • Basal cell carcinoma • Squamous cell carcinoma • Melanoma • Systemic lupus erythematosis • Hair follicles plug with oil and dead skin cells • Warts • May become infected and inflammed • Influenced by a number of factors (hormones, stress, etc)

Impetigo Psoriasis

• Highly contagious skin infection • Caused by Staphylococcus aureus • Buildup of skin cells due to overdivision • Common in young children • Dry, scaly, itchy patches • Blisters or sores usually appear on face, neck, hands, and • Thought to be an immune system problem diaper area • Genetic, but attacks are triggered by infection, stress, and cold

Decubitus ulcers (bedsores) Sunburn

• Skin injury resulting from prolonged pressure • Damage to skin from overexposure to UV light • Pressure on one side + bone on the other = lack of blood flow • Peeling = body’s attempt to shed damaged cells • Develop quickly, hard to treat, slow to heal (easier to prevent) • Damage to blood vessels underneath = increased blood flow • Common in those with limited mobility and warmth

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Burns Cancer • Causes • Heat • Chemicals Basal cell carcinoma • Electricity • Radiation • Dangers • Fluid and plasma protein loss → shock • Infection • Circulation Malignant melanoma • Kidney damage • Scarring • Uncontrolled cell growth due to genetic changes • Cells may metastasize and spread to other areas of the body

Burns Burns

• Classification • First degree • Second degree • Rule of nines • Epidermal damage only • Treatment • Epidermal and upper • Localized redness and pain dermal damage • Blistering, edema and pain

Surface area percentage reference This illustrates the difference between infants and adults

Burns

• Third degree 1st degree • Entire thickness of skin damaged burn • Gray-white, cherry red, or black • No initial edema or pain (nerve endings destroyed) • Skin grafting usually necessary

2nd degree burn

(a) Skin bearing partial thickness burn (1st and 2nd degree burns)

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Totals Burns 41/2% Anterior and posterior head and neck, 9% • Critical if: Anterior and posterior • >25% of the body has second-degree burns or worse Anterior upper limbs, 18% • >10% of the body has third-degree burns 41/ % trunk, 41/ % Anterior and posterior • Face, hands, or feet have third-degree burns 2 2 18% trunk, 36%

9% 9% (Perineum, 1%)

Anterior and posterior lower limbs, 36% 100%

Burns Burns

• Treatment • Cleaning and debridement • Treatment • Fluid therapy • Protection • Grafting • Prevention of infection • May require very high calorie and high protein diet

Skin: Developmental Aspects

• Advanced age • Decreased blood flow to skin • Thinning of epidermis • Loss of subcutaneous fat • Less collagen and elastin • Fewer melanocytes • Gray hair • Reduced glandular activity