Skin and Body: Functions, Structure, and Appendages

1. Chapter 4 Skin & Body Membranes

2. Integumentary System • Skin (cutaneous membrane) • Skin derivatives • -Sweat glands • -Oil glands • -Hairs • -Nails • Skin Functions • Protects deeper tissues • from: • wMechanical damage • wChemical damage • wBacterial damage • wThermal damage • wUltraviolet radiation • wDesiccation 2. Aids in heat regulation 3. Aids in excretion of uric acid 4. Synthesizes vitamin D

3. Skin Structure • The skin is composed of three layers: • 1. Epidermis- (outer layer) composed of • stratified squamous epithelium which is • keratinized • 2. Dermis- (middle layer) composed of dense • irregular connective tissue • -accessory organs: hair follicles, eccrine and • apocrine glands (sweat glands), sebaceous • glands (oil glands), blood vessels, nerve • endings, arrectorpili muscles, and capillary • beds. • 3. Hypodermis – (lower layer or • subcutaneous layer) composed of adipose tissue • contains arteries, veins, and large nerves

4. Layer of Epidermis • Stratum basale • wCells undergoing mitosis • wLies next to dermis • wcontains cells called melanocytes • Stratum spinosum • Stratum granulosum • Stratum lucidum • wOccurs only in thick skin (soles of feet • and palms of hands) • Stratum corneum • wShingle-like dead cells

5. Identify the layers of the thick skin tissue sample. Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale X - Ray NQ

6. Normal Skin Color Determinants • Melanin • Yellow, brown or black pigments • Carotene • Orange-yellow pigment from some vegetables • Hemoglobin • Red coloring from blood cells in dermis capillaries • Oxygen content determines the extent of red • coloring Melanin Pigment produced by melanocytes Melanocytes are mostly in the stratum basale Amount of melanin produced depends upon genetics and exposure to sunlight-"tanning effect"

7. Put the layers of the skin in order from outer most to inner most. hypodermis stratum basale stratum granulosum epidermis stratum lucidum dermis stratum spinosum stratum corneum Quanecia's Integument Rythym

8. Dermis • Two layers • 1. Papillary layer • ŸProjections called dermal papillae • (responsible for fingerprints) • ŸPain receptors • ŸCapillary loops • 2. Reticular layer • ŸBlood vessels • ŸGlands • ŸNerve receptors

9. Appendages of the Skin • Sebaceous glands • §Produce oil • Lubricant for skin • Kills bacteria • §Ducts that empty into hair • follicles • §Glands are activated at • puberty • Sweat glands: produce sweat • Two types: • a. Eccrine: produce watery sweat, • found all over body • - empty out on the epidermis • surface • b. Apocrine: produce sweat, fatty • substances, and protein • - Located in the axillary and pubic • regions • - Become active during puberty • - body odor due to bacteria • - empty into hair follicles. • Modified apocrine glands: • Ceruminous glands: ear, produce • cerumen or ear wax • Mammary glands: breasts, produce • and secrete milk • Function • Helps dissipate excess heat • Excretes waste products • Acidic nature inhibits bacteria growth

10. Appendages of the Skin • Hair • -Produced by hair bulb • -Hard dead keratinized epithelial cells • -Melanocytes provide pigment for hair color Hair Anatomy Central medulla Cortex surrounds medulla Cuticle on outside of cortex • Associated Hair Structures • Hair follicle • Arrector pilli • Smooth muscle • Sebaceous gland • Sudoriforous gland

11. Appendages of the Skin • Nails • Scale-like modifications of the epidermis • §Heavily keratinized • §Stratum basale beneath the nail bed • is responsible for growth • Lack of pigment makes them colorless Nail Structures Free edge Body Root of nail Eponychium – proximal nail fold that projects onto the nail body

12. Label the fingers! Cuticle Lanula Nail root Cuticle Nail matrix Body of nail Free edge Body of nail Nail bed

13. Appendages of the Skin Nerve receptors: The skin has receptors for pressure (Pacinian and Meissner’s corpuscles), pain, and temperature. Meissner’s corpuscles are located just below the surface of the epidermis and are sensitive to light pressure or touch, these are associated with “tickling sensations”. Pacinian Corpuscles are located deep in the dermis and are associated with strong touch and pressure. Root hair plexus are associated with each hair follicle and is responsible for the pain when your hair is pulled. Free nerve endings are scattered throughout the dermis and are specialized for the reception of heat, cold, or pain.

14. Temperature Regulation • •Your skin acts similar to a • radiator on a car to • disseminate heat that is • produced by cellular activity • in your body and muscular • contraction. • •This process is under the • control of the hypothalamus • in the brain. • •Negative feedback • mechanism

15. Temperature Regulation • • body temperature goes above the • set homeostatic value • • the blood vessels in the dermis dilate and • increase blood supply to the capillary • beds located there • • eccrine glands begin to secrete sweat • which moves to the surface of your • epidermis • • heat is transferred from the blood in your • capillaries, through the dermis and • epidermis, to the surface of the epidermis • and is absorbed by the water in the sweat • and vaporizes or evaporates it • • The blood has now lost heat and is at a • lower temperature and returns to the • inner body away form the surface to cool • the inner body structures

16. Temperature Regulation • • When the body’s temperature falls below the set • homeostatic value • • The arterioles constrict, forcing blood toward the interior organs • • The piliarrector muscles contract, generating heat, and raising the • hair trapping an insulating layer of air around the skin

17. Label the diagram! Eccrine sweat gland Eccrine sweat gland Hair root Dermis arrector pili muscle Root hair plexus Pacinian corpuscle Adipose tissue Sebaceous gland Free nerve ending vein Hypodermis Meissner's corpuscle Epidermis Sweat pore Hair follicle artery Hair shaft

18. A, D A, D E H B A H B G

19. Melanin Keratin T Corneum Shaft Dermis Cortex Cortex Medulla Medulla Cuticle Cuticle

20. hair bulb hypodermis dermal papillae sweat gland dermis nerves epidermis arrector pili hair follicle stratum corneum hair shaft adipose sebaceous gland

21. Skin Homeostatic Imbalances • Infections • 1. Athletes foot • Fungal infection • 2. Boils and carbuncles • Bacterial infection • 3. Cold sores • Viral • Infections and allergies • 4. Contact dermatitis • Exposures cause allergic reaction • 5. Impetigo • Bacterial infection • 6. Psoriasis • Cause is unknown • Triggered by trauma, infection, stress

22. Diseases and Disorders of the SkinImmunological • •Acne vulgaris: Due to • formation of sebum plugs • (white heads or black heads) • which block the sebaceous • gland and often trap bacteria • within the gland. • – Can become inflamed which can • lead to the secondary infections • of sweat gland or hair follicle • forming pustules or pimples

23. Diseases and Disorders of the SkinImmunological • •Chicken pox: due to a viral • infection (Herpes zoster) of • the skin which affects the • nerve ending • –results in the formation of • blisters that itch

24. Diseases and Disorders of the SkinImmunological • •Tinea: Ring worm, Athlete’s • foot, and Jock itch are all the • result of a fungal infection of • the skin. • –results in scaling, erythema • (reddening), and occasional • cracking of the skin that • burns or itches

25. Diseases and Disorders of the SkinImmunological • •Warts:due to infection by the • human papilloma virus. • –causes abnormal growth of the • epidermal layer • –Normally warts are benign but • some forms can transform and • become malignant (cervical • cancer) • –transmitted by direct contact from • one person to another

26. Diseases and Disorders of the SkinImmunological • •Impetigo: caused by an • infection of the epidermis by • Staphlococcus or • Streptococcus bacteria • –results in erythema, formation • of weeping blisters, that form a • yellow crusting on their surface • –highly contagious and common • in children

27. Diseases and Disorders of the SkinImmunological • •Contact dermatitis: due to an • allergic reaction with • materials which the skin has • made contact • –characterized by erythema, • edema, blistering and scaling of • the skin • –Itching is usually associated • with the area affected • –Poison Ivy is an example of this • disorder

28. Diseases and Disorders of the SkinImmunological • •MRSA infection is caused by • Staphylococcus aureus bacteria • — often called "staph." MRSA • stands for methicillin-resistant • Staphylococcus aureus • (resistant to antibiotics) • –can be fatal. • –Most MRSA infections occur in • hospitals or nursing homes and • dialysis centers. • –community-associated MRSA: • responsible for serious skin and • soft tissue infections and for a • serious form of pneumonia.

29. Matching 1. Characterized by dry cracked skin with burning and itching, usually between the toes. Dermatitis 2. Caused by the human papillomavirus. MRSA 3. A red itchy rash sometimes caused by poison ivy. Tinea Impetigo 4. A bacterial infection that usually occurs in children, characterized by crusty or oozing blisters. Warts 5. A serious staph infection.

30. Athlete's foot Dermatitis Boil Impetigo Chicken pox Herpes Warts Acne MRSA (boil) Psoriasis

31. Skin Homeostatic Imbalances • Burns • Tissue damage and cell death caused by heat, electricity, UV • radiation, or chemicals • Associated dangers • ü Dehydration & infection • ü Electrolyte imbalance • ü Circulatory shock • Rule of Nines • Determines the extent of burns • Body is divided into 11 areas- • -for quick estimation • Each area represents about 9%

32. Severity of Burns • •1st Degree burns: • – epidermis only • – result in redness and swelling (edema) • – Usually no scarring of tissue • •2nd Degree burns: • – epidermis and dermis, some damage to • accessory organs • – blistering but usually little scarring. • •3rd Degree burns: • – epidermis, dermis, and hypodermis • – destruction of dermal accessory organs, burn • is raw or blackened in appearance • – Severe scarring occurs, long healing period, • usually involving skin grafting

33. Critical Burns • Burns are considered critical if: • Over 25% of body has second degree burns • Over 10% of the body has third degree burns • There are third degree burns of the face, or feet

34. What degree of burn is shown in the pictures?

35. Skin Cancer • Cancer – abnormal cell mass • Two types • Benign • Does not spread (encapsulated) • Malignant • Metastasized (moves) to other parts of the body • «Skin cancer is the most common type of cancer

36. Skin Cancer Types Basal cell carcinoma üLeast malignant üMost common type üArises from statum basale Squamous cell carcinoma üMetastasizes to lymph nodes üEarly removal allows a good chance of cure

37. Skin Cancer Types • Malignant melanoma • Most deadly of skin cancers • Cancer of melanocytes • Metastasizes rapidly to lymph and blood vessels • Detection uses ABCD rule • ABCD Rule • A = Asymmetry • Two sides of pigmented mole do not match • B = Border irregularity • Borders of mole are not smooth • C = Color • Different colors in pigmented area • D = Diameter • Spot is larger then 6 mm in diameter