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Integumentary System Overview
- 1. Integumentary system PRESENTER: DR SOUMYA P 2ND YEAR PG SCHOLAR DEPARTMENT : KAYACHIKITSA
- 2. Contents Intoduction Skin anatomy Anatomy of accessory organs Skin physiology Interaction with other system Skin pathology Classification of skin diseases History taking and examinations Laboratory investigations
- 3. Introduction Skin = integument Skin+ accessory organs = integumentary system. The integumentary system comprises the skin and its appendages acting to protect the body from various kinds of damage, such as loss of water or damages from outside. It includes hair, glands and nails. It has a variety of additional functions; it may serve to waterproof, and protect the deeper tissues, excrete wastes, and regulate body temperature, and is the attachment site for sensory receptors to detect pain, sensation, pressure, and temperature,vitamin D synthesis.
- 4. Skin and its layers • Largest organ in the body • Constitutes of 15% of body weight • Surface area – 1.5 to 2.0 square meters 1. Epidermis 2. Dermis 3. Hypodermis ( subcutaneous layer)
- 5. Epidermis Most superficial layer of the skin Approx 10 to 30 cells thick ( epithelial) Cell types Keratinocytes -90% Melanocytes Merkel cells 10% Langerhens CLINICAL APPLICATION : KERATINIZATION - PSORIASIS
- 6. Stratum Basale Anatomy Stratum germinativum Deepest epidermal layer Attaches to basal lamina Cells bond to dermis via collagen fibres Finger like projection called dermal papillae in dermis Helps in stronger connection Cells- cuboidal shaped keratinocytes Grows constantly ,mitosis Pushed up old cells Applied aspect Cells – merkel cell – function as receptor- stimulating sensory nerve fibres Found in hairless skin. Abundant on surface of hand and feet. Melanocytes- produces pigment melanin - gives hair and skin its color -protect from u rays Note: skin color influenced by ,melanin and carotene – carrot, oxygenated haemoglobin Fingerprints-epidermal ridges
- 7. Stratum spinosum ANATOMY Spiny in appearance Desmosomsis protruding cell Interlock between cells Composed of 8to 10 layers of keratinocytes APPLIED ASPECT Langerhans cell –as a macrophage by engulfing bacteria and foreign body and damaged cell. Keratinocytes synthesise keratin and prevent water loss
- 8. Stratum granulosum Has a grainy appearance Cells become flattened,and cell membrane thicken, and generate large amount of protein keratin and keratohyalin After cell dies , keratin ,keratohyalin and cell membrane forms stratum lucidum And accessory structures of hair and nail
- 9. Stratum lucidum Smooth translucent layer It is found only in thick skin of palms ,soles,digits Cells are densely packed with eleidin , a clear protein rich in lipids, Transparent appearance
- 10. Stratum corneum ANATOMY Most superficial layer of epidermis The increased keratinization of cell It has 15 to 30 layers of cells Water is lost from skin in 2 ways Insensible perspiration water diffuses from stratum corneum and evaporates from skin -500 ml per day Sensible perspiration Water excreted by sweat glands. APPLIED ASPECT Helps prevent penetration of microbes and dehydration of underlying tissue Provides mechanical protection against abrasion Entire layer is replaced during a period of about 4 weeks. Cosmetic procedures , microdermabrasion help remove some of the dry upper layer and looks fresh and healthy.
- 11. Clinical application Some medications are toxic if swallowed, but safe if used topically (applied to surface of skin) • Certain topical antibiotics are fairly toxic if taken by mouth, butcan be applied to skin with minimal risk of systemic absorption;they are polar molecules that cannot pass through epidermis toreach blood vessels in dermis; allows for local effect only • Nonpolar substances cross epidermis much more easily;provides a convenient route of administration for certainmedications such as hormones in birth control patches • Unfortunately, many poisons and toxins (like thallium, a heavymetal) are also nonpolar; cross epidermis with same ease;therefore always good idea to wear gloves when handling chemicals
- 12. Dermis Dermis – highly vascular layer deep to epidermis Functions: Provides blood supply for epidermis Contains sensory receptors Anchors epidermis in place Cells Fibroblasts Macrophages Adipocytes
- 13. Papillary layer Loose areolar connective tissue Collagen + elastin Contains capillaries, lymphatics vessels and sensory neurons Dermal papillae capillaries Allow oxygen and nutrientsto diffuse into extracellular fluid of dermis; then into cells of avascular epidermis Tactile (Meissner) corpuscles – also found in dermal papillae; sensory receptors that respond to light touch stimuli; more numerous in regions of body where sensation is a primary function; skin of fingertips, lips, face, and external genitalia .
- 14. Reticular layer Dense irregular connective tissue Contains collagen and elastic fibres • Collagen bundles strengthen dermis and prevent traumatic injuries from damaging deeper tissues • Elastic fibers allow dermis to return to its original shape and size after stretching Rich in proteoglycans that draw water into ground substance; keeps skin firm and hydrated • Lamellated (Pacinian) corpuscles – found embedded within reticular layer; sensory receptors that respond mainly to changes in pressure and vibration associated with skin • Blood vessels, sweat glands, hairs, sebaceous glands, and adipose tissue are found in reticular layer
- 15. Applied aspect Dermal strength and elasticity Elastic fibres permit stretching and then recoil to original length Provide flexibility Fibres and water provide flexibility and resilience- known as skin turgor. Clinical Application: The patch drug delivery system. The transdermal patch is an increasingly popular drug delivery system. These patches are designed so that the drug molecules diffuse through the epidermis to the blood vessels in the dermis layer. A typical patch works well for small lipid-soluble molecules (for example, estrogen, nitroglycerin, and nicotine) that can make their way between epidermal cells.
- 16. Subcutaneous layer Deepest part of skin Connective tissue Adipose tissue(fat storage ) Site of subcutaneous injections using hypodermic needles
- 17. Dermal blood supply Cutaneous plexus Sub papillary plexus Applied aspect: Contusions / bruise
- 18. Nerve supply Control blood flow Adjust gland secretion rates Monitor sensory receptors - light touch – Meissner corpuscles-dermal papillae - deep pressure and vibration – lamellar (Pacinian)corpuscle-reticular layer.
- 19. Hair Types of hair- lanugo , vellus,terminal Protect and insulate Guard openings from particles and insects Serve as sensory receptors. Parts of hair Medulla Cortex cuticle Hair follicle: root Shaft Hair bulb matrix Arrector pili muscle: Involantary smooth muscle Contraction causes hair to stand up – goose bumps.
- 20. Glands Sweat glands Found al over the body and ducts directly open on to the skin surface. Sweat is derived from blood plasma and is a dilute solution of NaCl and urea. Eccrine (Mecocrine glands) – 99% water , to cool the skin ( thermore gulation ) palms, soles, and forehead Apocrine glands contains fatty acids , found near hair follicles ,responds to stress. Develop during early to mid puberty seen in armpits and genitalia. Bromhydrosis – body odour due to action of bacteria on fatty acids of sweat. Sebaceous glands- open into the hair follicle and release secretion called sebum , which softens the dead keratinocytes. The activity of the sebaceous glands increases during puberty because of .heightened levels of androgens
- 21. Nail The structure we know of as the nail is divided into six specificparts - the root, nail bed, nail plate, eponychium (cuticle), perionychium, and hyponychium It serves as a protective plate and enhances sensation of the fingertip.
- 22. FUNCTIONS OF THE INTEGUMENTARY SYSTEM Function of skin Structures involved Protection- chemical and mechanical trauma - uv rays -antigens - microbes Stratum corneum Melanocytes Langerhans Mast cells Fluid balance Stratum corneum Shock absorber Dermis Subcutaneous fat Sensation Sensory receptors Vitamin D synthesis Keratinocytes Temperature regulation Eccrine sweat glands Blod vessels Immunity Phagoctyes
- 23. Protective barrier Protection Microorganism Uvrays mechanical trauma fluid balance Sebaceous gland melanocytes keratinized hydrophobic lipid Acidic ph secrets melanin flexible surface repel covalent Molecule like salt an water Inhibits pathogens protects from uv rays protect from trauma maintain water balance
- 25. Thermoregulation
- 26. Sensation
- 27. Sensory Receptors of the Skin a) Free Nerve Endings are the tips of neuron processes that are sensitive to pain (nociceptors) or change in temperature (hot and cold). Commonly found in epithelia and connective tissue. b) Merkel’s (tactile) Endings are free nerve endings associated with a Merkel’s cell. This is a sensitive mechanoreceptor for sensing textures, edges and shapes. Encapsulated Nerve Endings: c) Pacinian (Lamellated) Corpuscles sense deep pressure, stretch, and vibration. Nerve ending is wrapped in a capsule of many layers of Schwann cells. Found in dermis of hands, feet, breasts and genitals. d) Krause’s End Bulbs are similar to Merkel’s disks, but are found in mucus membranes of the mouth and are cold temperature receptors. e) Meissner’s Corpuscles sense light touch and texture. Located in dermal papillae and are abundant in the lips. f) Ruffini’s Corpuscles are sensitive to stretch or compression of skin.
- 28. Vitamin D synthesis Insufficient Vit D3 causes rickets. essential for absorption of calcium and phosphate ions by small intestine. -liver and kidney together convert vitamin D3 into calcitriol it is released into blood Coverted into cholecalciferol - ( UV radiation ) Convetrs this inactive precussor to active form Precussor ( modified cholesterol molecule ) Epidermal cells consist of vitamin D precussor
- 30. Keratinocytes They act as the first line of innate immune defence against infection. They express Toll-like receptors (TLRs), which are pattern-recognition receptors (PRRs) that detect conserved molecules on pathogens and trigger an inflammatory Neutrophils are the first cells to respond to infection. They directly attack microorganisms by phagocytosis and by degranulation of toxic substances. Dendritic cells Dendritic cells possess TLRs that can be activated by microbial components Plasmacytoid dendritic cells (pDCs) produce large amounts of interferon-γ (IFN-γ) in response to viral infection. NK cells are cytotoxic lymphocytes that can eliminate virally infected cells and cancer cells without antigen presentation or priming. NK cells are activated by interferons or other cytokines released from macrophages. NK cells express inhibitor receptors that recognise MHC–I and prevent undesirable attacks on self. They can kill target cells through the perforin-granzyme pathway, which induces apoptosis (programmed cell death). Mast cells Mast cells are activated in response to allergic reactions and produce cytoplasmic granules filled with pre-formed inflammatory mediators, such as histamine. They release these granules when their high-affinity immunoglobulin E (IgE) receptor (FcεRI) on the mast cell surface reacts upon contact with stimuli such as allergens, venoms, IgE antibodies, and medications. These mediators can result in pruritic weals due to increased vascular permeability (urticaria). In rare cases, mast cell activation can lead to anaphylaxis, characterised by bronchoconstriction, dizziness, and syncope.
- 31. Skin pigmentation Normal skin color Melanin Haemoglobin carotene Abnormal Skin Colors • Albinism is a genetic lack of melanin. • Vitiligo is a patterned albinism thought to be caused by an autoimmune disorder that kills melanocytes in specific regions of the skin. • Hematoma is a bruise caused by clotted blood that escaped into the connective tissue of the dermis and hypodermis.
- 32. Skin markings / finger prints Skin markings – small visible lines in epidermis created by interaction between dermis and epidermis; best seen in thick skin of palmar surfaces of hands and fingers and plantar surface of feet and toes • Dermal ridges – found in areas where dermal papillae are more prominent due to presence of thick collagen bundles • Dermal ridges indent overlying epidermisto create epidermal ridges; enhance gripping ability of hands and feet: Epidermal ridges occur in characteristic patterns; loops, arches, and whorls; genetically determined and unique to each person Sweat pores open along these ridges and leave a thin film or fingerprint on things touched with fingers
- 33. Tension lines Tension lines / clevage lines Produced by parallel bundle of collagen and elastin fibres in the dermis Resist force applied to the skin During surgery it plays an important role.
- 34. Interactions with other body sytem Systems Its effects on skin Endocrine Thyroid function affects growth and texture of skin hair and nail. Hormones stimulate sebaceous glands. Adrenal hormones affect dermal blood supply. Renal Kidney remove swaste and mainatain normal ph . Respiratory Colour of skin nad nails are affected by changes in respiratory system Digestive Supply nutrients to skin Skeletal Provides a framework for skin Muscular Gives shape and support to skin Reproductive Provides sensory receptors for sexual stimulation
- 35. Pathology
- 46. ACNE Acne vulgaris – affects 96% of adolescents and young adults to some degree • Cause – accumulation of sebum and dead cells within sebaceous glands; produces a comedone (blackhead); occasionally becomes infected by Propionibacterium acnes, resulting in inflammation and formation of a pustule (pimple) • May be severe and cause permanent scarring in some individuals • Male sex hormones (like testosterone) are primary cause; tends to be more pronounced in males entering puberty; decreases and may disappear by age 20 25; may persist much longer in some individuals.
- 47. Skin Cancers • Skin cancer can be induced by UV rays of the sun and is most common in fair- skinned and elderly people. • Basal Cell Carcinoma – arises from keratinocyes in the stratum basale that transform and invade the dermis – treated by surgical removal and/or radiation • squamous cell carcinoma – arises from keratinocytes in the stratum spinosum – metastasis to the lymph nodes can be lethal • melanoma (most deadly skin cancer) – arises from melanocytes – ABCD: asymmetry, border irregular, color mixed, diameter over 6 mm
- 48. Integumentary examination /History taking
- 49. Continued…
- 50. Physical examination • Inspection • Around the bedside • The patient • Basics of rash description • Site; shape; size; symmetry • Colour • Border • Specifics • Excoriation • Ulcer/erosion • Weeping • Crusting, hyperkeratosis or scale • visibility of blood vessels • Odour • Palpation • Tenderness (ask the patient first!) • Surface texture • Elevation • Skin thickness • Blanching • Tissue loss • Tethering • Associated signs • Temperature • Oedema • Crepitus
- 51. Types of lesion Lesion Description Example Primary Lesions Macule <0.5cm, flat, circumscribed area of altered skin colour Vitiligo (small) Patch ≥0.5cm, flat, circumscribed area of altered skin colour Vitiligo (large) Papule <0.5cm, circumscribed elevation of skin Molluscum contagiosum Plaque ≥0.5cm, circumscribed elevation of skin Psoriasis Weal Transient, smooth, slightly raised lesion, characteristically with a pale centre and a pink margin Urticaria Vesicle (blister) <0.5cm, circumscribed, fluid- containing elevation Acute eczema e.g. pompylox
- 52. Bulla (blister) ≥0.5cm, circumscribed, fluid- containing elevation Burn, friction Pustule Visible collection of pus Staphylococcal folliculitis Abscess Localised collection of pus in a cavity Bacterial infection Erythema Redness, blanching Erythema nodosum Purpura Redness, non-blanching, secondary to collections of red blood cells Vasculitis, platelet or clotting defect Telangiectasis Dilated capillaries visible on the skin surface Side-effect of topical steroids Secondary Lesions Scale Thickened, loose, readily detached fragments of stratum corneum Psoriasis
- 55. Examination aids / diagnostic aids Ruler Lighting Penlight Gloves Magnifying glass Woods lamp
- 56. Ruler Accurately records the size of a lesion on successive examination. Measure in longest axis first and then in the perpendicular axis.
- 57. Dermatoscopy Distinguish benign from malignant tumors. Melanoma , basal cell carcinoma..
- 58. penlight
- 59. Diascopy Vascular - blanches non vascular or haemorrhagic – no blanching Ex : nevus, petechia
- 60. Woods lamp Tinea capitis Pityriasis versicolor Vitiligo melasma
- 61. Skin biopsy Skin biopsy Biopsy may be used to provide a histopathological specimen to aid diagnosis and guide further management. Always provide relevant history, description and differential diagnosis to assist the histopathologist. Histology may not be able to differentiate between some cases of dysplastic naevi and melanoma so that any case of incompletely excised 'dysplastic naevus' should be referred for a further excision.
- 62. Patch test A patch test is a diagnostic method used to determine which specific substances cause allergic inflammation of a patient's skin. Patch testing helps identify which substances may be causing a delayed- type allergic reaction in a patient, and may identify allergens not identified by blood testing or skin prick testing.
- 63. Skin prick test Skin prick testing is an allergy test used to identify allergens responsible for triggering symptoms in allergic diseases skin prick testing is useful in the diagnosis of other allergies such as aeroallergens causing hay fever, food allergy, latex allergy, drug allergy, and bee and wasp venom allergy.