Lesson-4.-Integumentary-System (1).pdfsd
- 2. • Integumentary System – consists of the skin and its accessory organs – hair, nails, and cutaneous glands • Most visible system and more attention paid to this organ system • Inspection of the skin, hair, and nails is significant part of a physical exam 6-2 http://essentialoilsforguide.com/body-systems/integumentary-system/
- 3. • Skin is the most vulnerable organ – exposed to radiation, trauma, infection, and injurious chemicals • Receives more medical treatment than any other organ system • Dermatology – scientific study and medical treatment of the integumentary system 6-3 http://www.sevenhillshospital.com/our-specialities/cosmetic-dermatology.html
- 4. The body’s largest and heaviest organ covers area of 1.5 -2.0 m2 15 % of body weight Consists of two layers: epidermis – stratified squamous epithelium dermis – connective tissue layer Hypodermis – another connective tissue layer below the dermis 6-4 Sensory nerve fibers Apocrine sweat gland Piloerector muscle Lamellar (pacinian) corpuscle (pressure receptor) Hair bulb Motor nerve fibers Cutaneous blood vessels Hypodermis (subcutaneous fat) Epidermis Merocrine sweat gland Hair receptor Dermal papilla Blood capillaries Hair follicle Sebaceous gland Hairs Sweat pores Dermis Tactile corpuscle (touch receptor)
- 5. Most skin is 1 – 2 mm thick Ranges from 0.5 mm on eyelids to 6 mm between shoulder blades Thick skin – on palms and sole, and corresponding surfaces on fingers and toes has sweat glands, but no hair follicles or sebaceous (oil) glands epidermis 0.5 mm thick Thin skin – covers rest of the body epidermis about 0.1 mm thick possesses hair follicles, sebaceous glands and sweat glands 6-5 Sensory nerve fibers Apocrine sweat gland Piloerector muscle Lamellar (pacinian) corpuscle (pressure receptor) Hair bulb Motor nerve fibers Cutaneous blood vessels Hypodermis (subcutaneous fat) Epidermis Merocrine sweat gland Hair receptor Dermal papilla Blood capillaries Hair follicle Sebaceous gland Hairs Sweat pores Dermis Tactile corpuscle (touch receptor)
- 6. • Resistance to trauma and infection – keratin – acid mantle • Other barrier functions – waterproofing – UV radiation – harmful chemicals 6-6 • Vitamin D synthesis – skin first step – liver and kidneys complete process https://www.bbraun.co.uk/en/patients/wound-healing/knowledge-series.html
- 7. • Sensation – skin is our most extensive sense organ • Thermoregulation – thermoreceptors – vasoconstriction / vasodilation • Nonverbal communication – acne, birthmark, or scar • Transdermal absorption – administration of certain drugs steadily through thin skin – adhesive patches 6-7 http://www.beautyhelm.com/birthmarks/what-do-birthmark-mean-meaning/ http://www.poison.org/articles/2012-aug/using-skin-patch-medicines-safely
- 8. Epidermis – keratinized stratified squamous epithelium Five types of cells of the epidermis stem cells undifferentiated cells that give rise to keratinocytes in deepest layer of epidermis (stratum basale) keratinocytes great majority of epidermal cells synthesize keratin 6-8
- 9. melanocytes occur only in stratum basale synthesize pigment melanin that shields DNA from UV radiation branched processes that spread among keratinocytes tactile (merkel) cells in basal layer of epidermis touch receptor cells associated with dermal nerve fibers dendritic (Langerhans) cells macrophages originating in bone marrow that guard against pathogens found in stratum spinosum and granulosum stand guard against toxins, microbes, and other pathogens that penetrate skin 6-9
- 10. Cell Types and Layers of Epidermis 6-10 Dermal blood vessels Tactile cell Melanocyte Dead keratinocytes Exfoliating keratinocytes Living keratinocytes Dendritic cell Stem cell Dermis Stratum lucidum Stratum basale Stratum granulosum Stratum spinosum Stratum corneum Sweat pore Tactile nerve fiber Dermal papilla Sweat duct
- 11. A single layer of cuboidal to low columnar stem cells and keratinocytes resting on the basement membrane melanocytes and tactile cells are scattered among the stem cells and keratinocytes Stem cells of stratum basale divide give rise to keratinocytes that migrate toward skin surface replace lost epidermal cells 6-11
- 12. Consists of several layers of keratinocytes Thickest stratum in most skin in thick skin, exceeded by stratum corneum Deepest cells remain capable of mitosis cease dividing as they are pushed upward 6-12
- 13. Produce more and more keratin filaments which causes cell to flatten higher up in this stratum, the flatter the cells appear Dendritic cells found throughout this stratum Named for artificial appearance created in histological section numerous desmosomes and cell shrinkage produces spiny appearance 6-13
- 14. Consists of 3 to 5 layers flat keratinocytes Contain coarse dark-staining keratohyalin granules Produces lipid-filled vesicles that release a glycolipid by exocytosis of waterproof the skin forms a barrier between surface cells and deeper layers of the epidermis cuts off surface strata from nutrient supply 6-14
- 15. • Seen only in thick skin • Thin translucent zone superficial to stratum granulosum • Keratinocytes are densely packed with eleidin • Cells have no nucleus or other organelles • Zone has a pale, featureless appearance with indistinct boundaries 6-15
- 16. • Up to 30 layers of dead, scaly, keratinized cells • Form durable surface layer – surface cells flake off (exfoliate) • Resistant to abrasion, penetration, and water loss 6-16
- 17. Keratinocytes are produced deep in the epidermis by stem cells in stratum basale some deepest keratinocytes in stratum spinosum also multiply and increase their numbers Mitosis requires an abundant supply of oxygen and nutrients deep cells acquire from blood vessels in nearby dermis once epidermal cells migrate more than two or three cells away from the dermis, their mitosis ceases 6-17
- 18. Newly formed keratinocytes push the older ones toward the surface In 30 - 40 days a keratinocyte makes its way to the skin surface and flakes off slower in old age faster in skin injured or stressed calluses or corns – thick accumulations of dead keratinocytes on the hands or feet 6-18
- 19. Dermis – connective tissue layer beneath the epidermis Ranges from 0.2 mm (eyelids) – 4 mm (palms & soles) Composed mainly of collagen with elastic fibers, reticular fibers, and fibroblasts Well supplied with blood vessels, sweat glands, sebaceous glands, and nerve endings Dermal papillae - extensions of the dermis into the epidermis forming the ridges of the fingerprints Layers papillary layer reticular layer is deeper part of dermis 6-19
- 20. Hypodermis • Subcutaneous tissue • More areolar and adipose than dermis • Pads body • Binds skin to underlying tissues • Drugs introduced by injection • highly vascular & absorbs them quickly • Subcutaneous fat • energy reservoir • thermal insulation • 8% thicker in women 6-20 6-20
- 21. • Melanin – most significant factor in skin color – produced by melanocytes – accumulate in the keratinocytes of stratum basale and stratum spinosum – eumelanin – brownish black – pheomelanin - a reddish yellow sulfur-containing pigment 6-21
- 22. • People of different skin colors have the same number of melanocytes – dark skinned people • produce greater quantities of melanin • melanin granules in keratinocytes more spread out than tightly clumped • melanin breaks down more slowly • melanized cells seen throughout the epidermis – light skinned people • melanin clumped near keratinocyte nucleus • melanin breaks down more rapidly • little seen beyond stratum basale • Amount of melanin also varies with exposure to ultraviolet (UV) rays of sunlight 6-22
- 23. • Hemoglobin - red pigment of red blood cells – adds reddish to pinkish hue to skin • Carotene - yellow pigment acquired from egg yolks and yellow/orange vegetables – concentrates in stratum corneum and subcutaneous fat Other Factors in Skin Color 6-23
- 24. Cyanosis - blueness of the skin from deficiency of oxygen in the circulating blood airway obstruction (drowning or choking) lung diseases (emphysema or respiratory arrest) cold weather or cardiac arrest Erythema – abnormal redness of the skin due to dilated cutaneous vessels 6-24 http://www.medicinenet.com/image-collection/erythema_multiforme_1_picture/picture.htm http://diseasespictures.com/cyanosis/
- 25. Pallor – pale or ashen color when there is so little blood flow through the skin that the white color of dermal collagen shows through emotional stress, low blood pressure, circulatory shock, cold, anemia Albinism – genetic lack of melanin that results in white hair, pale skin, and pink eyes have inherited recessive, nonfunctional tyrosinase allele 6-25 https://www.researchgate.net/figure/23766802_fig1_Figure-1-Marked-skin-pallor-in-the-distribution-of-the-right-infra-orbital-nerve https://siliwuri.blogspot.com/2016/05/albinism.html
- 26. Jaundice - yellowing of skin and sclera due to excess of bilirubin in blood cancer, hepatitis, cirrhosis, other compromised liver function Hematoma – (bruise) mass of clotted blood showing through skin Bronzing - golden-brown color of Addison disease (deficiency of glucocorticoid hormone) 6-26 http://nursingexercise.com/jaundice-disease-causes-sign-treatment/ http://www.accidentlawyerstlouis.com/bruises-contusions-hematomas/ https://pocketdentistry.com/4-examination-of-the-head-and-neck/
- 27. • Friction ridges – the markings on the fingertips that leave oily fingerprints on surfaces we touch – everyone has a unique pattern formed during fetal development and remain unchanged throughout life – not even identical twins have identical fingerprints – allow manipulation of small objects 6-27 http://www.intellitech.com.pk/support.html http://studydroid.com/printerFriendlyViewPack.php?packId=363646
- 28. • Flexion lines (flexion creases) – lines on the flexor surfaces of the digits, palms, wrists, elbows – marks sites where the skin folds during flexion of the joints 6-28 http://medicine.academic.ru/114290/flexion_crease
- 29. • Freckles and moles – tan to black aggregations of melanocytes – freckles are flat, melanized patches – moles (nevus) are elevated melanized patches often with hair • moles should be watched for changes in color, diameter, or contour • may suggest malignancy (skin cancer) 6-29 https://www.queenofsunscreen.com/single-post/2016/01/05/Moles-vs-Freckles-Whats-the-Difference
- 30. • Hemangiomas (birthmarks) – patches of discolored skin caused by benign tumors of dermal blood capillaries – some disappear in childhood -- others last for life – capillary hemangiomas, cavernous hemangiomas, port-wine stain 6-30 https://www.babble.com/baby/common-birthmarks/
- 31. • Hair is found almost everywhere on the body except: – palms and soles – ventral and lateral surface of fingers and toes – distal segment of the finger – lips, nipples, and parts of genitals 6-31
- 32. • Limbs and trunk have 55 – 70 hairs per cm2 – face about 10 times as many – 30,000 hairs in a man’s beard – 100,000 hairs on an average person’s scalp – number of hairs does not differ much from person to person or even between sexes • differences in appearance due to texture and pigmentation of the hair 6-32
- 33. • Three kinds of hair grow over the course of our lives – lanugo – fine, downy, unpigmented hair that appears on the fetus in the last three months of development 6-33
- 34. – vellus – fine, pale hair that replaces lanugo by time of birth • two-thirds of the hair of women • one-tenth of the hair of men • all of hair of children except eyebrows, eyelashes, and hair of the scalp 6-34
- 35. – terminal – longer, coarser, and usually more heavily pigmented • forms eyebrows, eyelashes, and the hair of the scalp • after puberty, forms the axillary and pubic hair • male facial hair and some of the hair on the trunk and limbs 6-35
- 36. • Hair is divisible into three zones along its length – bulb – a swelling at the base where hair originates in dermis or hypodermis • only living hair cells are in or near bulb – root – the remainder of the hair in the follicle – shaft – the portion above the skin surface • Dermal papilla – bud of vascular connective tissue encased by bulb – provides the hair with its sole source of nutrition • Hair matrix – region of mitotically active cells immediately above papilla – hair’s growth center 6-36 Hair bulb Hair cortex Hair medulla Hair matrix Connective tissue root sheath Epithelial root sheath Dermal papilla
- 37. Three layers of the hair in cross- section from inside out Medulla Cortex Cuticle Texture – related to differences in cross-sectional shape straight hair is round wavy hair is oval curly hair is relatively flat 6-37
- 38. Color – due to pigment granules in the cells of the cortex brown and black hair is rich in eumelanin red hair – low eumelanin but a high pheomelanin blond hair intermediate amount of pheomelanin ; very little eumelanin Gray and white hair scarcity or absence of melanin in the cortex and the presence of air in the medulla 6-38
- 39. • Hair cycle – consists of three developmental stages – Anagen - growth stage - 90% of scalp follicles at any given time • lasts 6-8 years in young adult – Catagen - shrinking stage (2-3 weeks) • base of hair keratinizes into a hard club, and hair is now known as club hair – loses its anchorage – easily pulled out by brushing – Telogen - resting stage (1-3 months) 6-39 Epidermis Dermis Hair matrix Sebaceous gland Old club hair Piloerector New hair Bulge Club hair (detached from matrix) Club Dermal papilla Degeneration of lower follicle Hair bulb 2 3 Anagen (early) Anagen (mature) Catagen Telogen 1
- 40. • Club hair may fall out during catagen or telogen – or pushed out by new hair in the next anagen phase • We lose about 50 – 100 scalp hairs daily • Alopecia – thinning of the hair or baldness • Pattern baldness – the condition in which hair loss from specific regions of the scalp rather than thinning uniformly – combination of genetic and hormonal influence – baldness allele is dominant in males and expressed only in high testosterone levels – testosterone causes terminal hair in scalp to be replaced by vellus hair • Hirsutism – excessive or undesirable hairiness in areas that are not usually hairy 6-40
- 41. • Most hair on trunk and limbs is vestigial – little present function – warmth in ancestors • Hair receptors alert us of parasites crawling on skin • Scalp helps retain heat and prevents sunburn • Pubic and axillary hair signify sexual maturity and aids in transmission of sexual scents • Guard hairs (vibrissae) - guard nostrils and ear canals • Nonverbal communication – Eyelashes and eyebrows 6-41
- 42. 6-42 Free edge Lunule Nail plate Nail body Nail fold Nail groove Nail fold Nail bed Nail matrix Eponychium (cuticle) Nail root Free edge Nail body Eponychium (cuticle)
- 43. Nails • Derivative of stratum corneum – densely packed cells filled with hard keratin • Flat nails allow for fleshy, sensitive fingertips • Growth rate is 1 mm per week – new cells added by mitosis in the nail matrix – nail plate is visible part of nail • medical diagnosis of iron deficiency = concave nails
- 44. • Two kinds of sweat (sudoriferous) glands • merocrine (eccrine) sweat glands • most numerous skin glands - 3 to 4 million in adult skin • watery perspiration that helps cool the body (500 ml per day) – apocrine sweat glands • occur in groin, anal region, axilla, areola, bearded area in mature males • produce sweat that is thicker, milky, and contains fatty acids • scent glands that respond to stress and sexual stimulation • pheromones – chemicals that influence the physiology of behavior of other members of the species • bromhidrosis - disagreeable body odor produced by bacterial action on fatty acids 6-44 (a) Apocrine gland Lumen Secretory cells
- 45. • Sebum – oily secretion produced by sebaceous glands • Flask-shaped glands with short ducts opening into hair follicle • Holocrine gland – secretion consists of broken- down cells – replaced by mitosis at base of gland • Keeps skin and hair from becoming dry, brittle, and cracked • Lanolin – sheep sebum 6-45 (c) Sebaceous gland Gland Hair follicle
- 46. Found only in external ear canal their secretion combines with sebum and dead epithelial cells to form earwax (cerumen) keep eardrum pliable waterproofs the canal kills bacteria makes guard hairs of ear sticky to help block foreign particles from entering auditory canal Simple, coiled tubular glands with ducts that lead to skin surface 6-46
- 47. • Skin cancer – induced by the ultraviolet rays of the sun – most often on the head and neck – most common in fair-skinned people and the elderly – one of the most common cancers – one of the easiest to treat – has one of the highest survival rates if detected and treated early – three types of skin cancer named for the epidermal cells in which they originate – basal cell carcinoma, squamous cell carcinoma, and malignant melanoma 6-47
- 48. 6-48 - Most common type - Least dangerous because it seldom metastasizes - Forms from cells in stratum basale - Lesion is small shiny bump with central depression and beaded edges (a) Basal cell carcinoma
- 49. 6-49 - Skin cancer that arises from melanocytes - Less than 5% of skin cancers, but most deadly form - Treated surgically if caught early - Metastasizes rapidly - unresponsive to chemotherapy - usually fatal - Greatest risk factor – familial history of malignant melanoma - High incidence in men, redheads, people who experience severe sunburn in childhood ABCD--asymmetry, border irregular, color mixed and diameter over 6 mm (c) Malignant melanoma
- 50. 6-50 - Arise from keratinocytes from stratum spinosum - Lesions usually appear on scalp, ears, lower lip, or back of the hand - Have raised, reddened, scaly appearance later forming a concave ulcer - Chance of recovery good with early detection and surgical removal - Tends to metastasize to lymph nodes and may become lethal (b) Squamous cell carcinoma
- 51. • UVA and UVB are improperly called “tanning rays” and “burning rays” • Both thought to initiate skin cancer • Sunscreens protect you from sunburn but unsure if provide protection against cancer – chemical in sunscreen damage DNA and generate harmful free radicals 6-51
- 52. • Burns – leading cause of accidental death – fires, kitchen spills, sunlight, ionizing radiation, strong acids or bases, or electrical shock – deaths result primarily from fluid loss, infection and toxic effects of eschar – burned, dead tissue debridement – removal of eschar • Classified according to the depth of tissue involvement – First-degree burns – partial thickness burn - involve only the epidermis • marked by redness, slight edema, and pain • heal in a few days • most sunburns are first degree burns 6-52
- 53. – Second-degree burns – partial thickness burn - involve the epidermis and part of the dermis • leaves part of the dermis intact • red, tan, or white • two weeks to several months to heal and may leave scars • blistered and very painful 6-53
- 54. – Third-degree burn – full thickness burn – the epidermis and all of the dermis, and often some deeper tissues (muscles or bones) are destroyed • often require skin grafts • needs fluid replacement and infection control 6-54
- 55. • Third-degree burns require skin grafts • Graft options – autograft - tissue taken from another location on the same person’s body • split-skin graft – taking epidermis and part of the dermis from an undamaged area such as the thigh or buttocks and grafting it into the burned area – isograft - skin from identical twin • Temporary grafts (immune system rejection) – homograft (allograft) -- from unrelated person – heterograft (xenograft) -- from another species – amnion from afterbirth – artificial skin from silicone and collagen 6-55