Integumentary System PDF

Integumentary System PARA 1002 1 Integumentary System The integumentary system is made up of the skin and its appendages (sweat glands, oil glands, hair and nails) The skin is actually the largest of all the organs (~7% of total body...

Integumentary System PARA 1002 1 Integumentary System The integumentary system is made up of the skin and its appendages (sweat glands, oil glands, hair and nails) The skin is actually the largest of all the organs (~7% of total body wt.) What are the functional roles of the Integumentary System? PARA 1002 2 1  Integumentary Objectives Describe epidermis and dermis (what is the hypodermis?) Understand the function of each skin layer Describe factors relating to skin colour and appearance Identify the appendages of the skin Identify various skin disorders Explain age-related skin changes PARA 1002 3 Skin Epidermis Dermis Hypodermis What is the role of keratin? PARA 1002 4 2  Skin Layers Epidermis (keratinized stratified squamous epithelium) - Contains keratinocytes, melanocytes, Merkel cells, and Langerhans cells - 5 layers (thick skin) or 4 layers (thin skin): stratum basale, stratum spinosum, stratum granulosum, stratum lucidum (absent in thin skin), stratum corneum - The stratum corneum is composed mostly of dead keratinocytes and glycoprotein, forming a waterproof layer that “flakes off” daily - Mechanical / physical protection and produces antibiotics and enzymes that protect the skin PARA 1002 5 Keratin PARA 1002 6 3  Skin Layers Dermis (connective tissue) - Typical cells and fibre types found in connective tissue proper - Living tissue / contains a vast network of blood vessels (thermoregulation!) and nerve fibres - Actually “holds the body together” - Gives strength and resilience to the skin through collagen and elastin fibres - Skin surface markings (flexure lines) such as fingerprints and palm lines originate deep in the dermis PARA 1002 7 Superficial vs Deep Laceration PARA 1002 8 4  Epidermal Growth and Repair Epidermis is continuously “shedding” and being replaced by the cells beneath As the stratum corneum flakes off (a few hundred million go down the shower drain each morning!) cells from the stratum granulosum begin to keratinize and eventually push up to replace them Accelerated by mechanical abrasion High regenerative capacity  cuts / abrasions to epidermis and superficial dermis heal fairly quickly PARA 1002 9 Skin Colour Results from various combinations of the pigments: melanin, carotene and hemoglobin Melanin - Based on the amino acid tyrosine - Colour ranges from yellow to brown to black Carotene - Obtained from vegetables such as carrots - Yellow-orange colour - Concentrated in stratum corneum Hemoglobin - Oxygenated hemoglobin is bright red - Lends a pink hue to Caucasian skin PARA 1002 10 5  Individual Skin Colour PARA 1002 11 Significance of Skin Colour Temporary or permanent changes in individual skin colour may result from various causes from a simple homeostatic response to a serious disease or disorder Pallor – an abnormal paleness of the skin that may be due to low levels of melanin or reduction in the amount of surface blood (many possible causes) Erythema – increased redness of the skin resulting from numerous simple and serious causes PARA 1002 12 6  Significance of Skin Colour Cyanosis – a bluish colouration of the skin due to increased levels of deoxygenated hemoglobin in the blood Jaundice – a yellowing of the skin and eyes resulting from increased levels of the bile pigment bilirubin in the blood (liver disorder) Many of these colour changes are more difficult to observe in skin with a naturally darker pigment… Where else do we see these changes? PARA 1002 13 Significance of Skin Colour PARA 1002 14 7  Significance of Skin Colour PARA 1002 15 Skin Disorders Bacterial Infections – - impetigo (contagious), boils (furuncles) Viral Infection – - warts (papillomavirus), herpes (HSV), shingles, chicken pox Parasitic Disorders – - lice, scabies Fungal Infections – - Tinea (ringworm, jock itch, athlete’s foot) Lesions – - psoriasis, keloids, nevi (moles), decubitus ulcers (bedsores) PARA 1002 16 8  Appendages of the Skin Hair – dead keratinized cells secreted from the hair living hair follicle Sebaceous glands – secrete sebum which protects and conditions the skin Sweat glands – secrete sweat (a blood filtrate) which is mostly water (99%) Nails – scale-like modification of the epidermis PARA 1002 17 Burns Serious threat to life Causes rapid fluid loss and reduced blood flow Infection risk is high Classified by severity – 1st, 2nd and 3rd degree PARA 1002 18 9  Burns 1st degree burns - Only damage to the epidermis - Redness, swelling and pain - No blistering and heals within a few days - Sunburn is a 1st degree burn 2nd degree burns - Damage to the epidermis and upper part of the dermis - Redness, swelling, pain and blisters - 3 to 4 weeks healing time with slight possibility of infection PARA 1002 19 Burns 3rd degree burns - Consume entire thickness of the skin and may damage hypodermis - Appear white, red or blackened - Severe likelihood of extreme fluid loss and infection before natural skin regeneration (intervention) - Dermal structures damaged PARA 1002 20 10  Burns 1st and 2nd degree burns are considered partial thickness burns… 3rd degree burns and above are full thickness burns… What are 4th degree burns? What about 5th, 6th degree burns? PARA 1002 21 Rule of Nines A guideline to estimate the extent of burns to the body Considered severe if: -3rd degree burns over > 10% of body -2nd degree burns over > 25% of body -3rd degree burns on face, hands or feet PARA 1002 22 11  Thermoregulation & Homeostasis What is the role of the skin? PARA 1002 23 Thermoregulation & Homeostasis PARA 1002 24 12  Skin Cancer Basal cell carcinoma Squamous cell carcinoma Melanoma PARA 1002 25 Ageing During adolescence, androgens cause acne Skin is “at its peak” in the 20’s and 30’s During middle age: - Collagen production decreases and skin loses some elastic properties - Skin dries more easily and wrinkles appear - Skin is less “tough” and heals more slowly It is now well documented that the majority of the ageing affects on skin are directly attributable to unprotected sun/UV exposure PARA 1002 26 13 27 Skin Disorders Impetigo PARA 1002 28 14  Skin Disorders Athlete’s Foot Ringworm Jock Itch PARA 1002 29 Skin Disorders Herpes Chickenpox Warts PARA 1002 30 15  Skin Disorders Bed Sores Keloids Psoriasis Nevi PARA 1002 31 Just a bedsore? PARA 1002 32 16