skin functions

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Slide 2: 

Skin M.Yousry 2

Slide 3: 

Skin M.Yousry 3

Structure of epidermal barrier : 

Skin M.Yousry 4 Structure of epidermal barrier

Structure of coneocytes barrier : 

Skin M.Yousry 5 Structure of coneocytes barrier

Slide 6: 

Skin M.Yousry 6

Slide 7: 

Skin M.Yousry 7

Dermis with CutaneousAppendages : 

Skin M.Yousry 8 Dermis with CutaneousAppendages

Skin Structure in RelationTo Thermoregulation : 

Skin M.Yousry 9 Skin Structure in RelationTo Thermoregulation The primary function of the skin vasculature is heat regulation Nutrition is second

Slide 10: 

Skin M.Yousry 10

Vascular Dilatation : 

Skin M.Yousry 11 Vascular Dilatation

Immunological Functionsof The Skin : 

Skin M.Yousry 12 Immunological Functionsof The Skin The physical barrier that is the skin is the front line in defense of the body against the invasion of foreign organisms and substances. BUT it is an imperfect barrier The second line of defense is the Skin ImmuneSystem (SIS) The Skin IS an Immunologic Organ

Functional Properties of S.I.S. : 

Skin M.Yousry 13 Functional Properties of S.I.S. Involved in normal homeostasis and host defense mechanisms against foreign invaders. immune response to new cutaneous antigens immunity to “old” antigens avoidance of deleterious immune response

Cells in the Epidermis involvedin the SIS : 

Skin M.Yousry 14 Cells in the Epidermis involvedin the SIS Keratinocytes, differentiate into corneocytes which form the outer protective sheath & important cytokine producing cells involved in the Immune Surveillance system. Langerhans cells, bone marrow derived macrophages, are important in cutaneous immune surveillance

Skin Immune System : 

Skin M.Yousry 15 Skin Immune System Keratinocytes Derived Cytokines Resting Keratinocytes: IL-1a, IL-6, IL-7, IL-11, IL-15,TNF-a, GM-CSF, G-CSF, TGF-ß Activated keratinocytes: IL-1a, IL-6, IL-7, IL-10, 11, 12 IL-13, 15, TNF-a, IL-8, GRO-2, Rantes, IL-3, GMCSF G-CSF, M-CSF, INF-a/ß

Langerhans Cells : 

Skin M.Yousry 16 Langerhans Cells Bone marrow derived macrophage Functions to present antigens to T lymphocytes T-cells do not recognize these antigens without prior processing by the Langerhans cells

Cells of the Epidermis : 

Skin M.Yousry 17 Cells of the Epidermis

Cells in the Dermis involved inthe SIS : 

Skin M.Yousry 18 Cells in the Dermis involved inthe SIS Mast cells T lymphocytes Monocytes –macrophages & other dendritic cells Fibroblasts – produce collagen Not present in normal skin. PMNL, EOS, BASO

Cutaneous & non-CutaneousCells involved in the SIS : 

Skin M.Yousry 19 Cutaneous & non-CutaneousCells involved in the SIS 1/2 of cells in skin are related to or part of the immune system Keratinocytes Dendritic Ag. presenting cells (Langerhans Cells) Macrophages / monocytes Granulocytes Mast cells/lymphatic / vascular endothelial cells T lymphocytes

Slide 20: 

Skin M.Yousry 20

Functional Impairment of SIS : 

Skin M.Yousry 21 Functional Impairment of SIS By UV light Neoplasms or infections (HIV) Disruption/destruction of the barrier

Interference With BarrierFunction of The Skin : 

Skin M.Yousry 22 Interference With BarrierFunction of The Skin Mild - inflammatory dermatoses Cutaneous functions retained Moderate - Bullous diseases Cutaneous functions moderately impaired Severe - Toxic Epidermal Necrolysis (TEN) Cutaneous functions destroyed

Interference With BarrierDermatitis / Eczema : 

Skin M.Yousry 23 Interference With BarrierDermatitis / Eczema Mild Interference Functions retained

Acute Allergic Contact Dermatitis : 

Skin M.Yousry 24 Acute Allergic Contact Dermatitis

Poison Ivy : 

Skin M.Yousry 25 Poison Ivy

Subacute Allergic ContactDermatitis : 

Skin M.Yousry 26 Subacute Allergic ContactDermatitis

Pathophysiology of AllergicContact Dermatitis : 

Skin M.Yousry 27 Pathophysiology of AllergicContact Dermatitis Type IV cell mediated reaction, marked by 1. Afferent (antigen recognition/ sensitization) phase. 2. Efferen (response/elicitation) phase.

Allergic Contact Dermatitis : 

Skin M.Yousry 28 Allergic Contact Dermatitis Sensitization Phase Langerhans cells load the antigen in the epidermis and migrate to draining lymph nodes. Activation of naïve T lymphocytes by LC T cells mediate contact sensitivity.

Allergic Contact DermatitisSensitization : 

Skin M.Yousry 29 Allergic Contact DermatitisSensitization

Allergic Contact Dermatitis : 

Skin M.Yousry 30 Allergic Contact Dermatitis Elicitation Phase After subsequent contact of skin with the antigen, specific T lymphocytes are activated in the dermis and epidermis and are responsible for the cutaneous lesions.

Allergic Contact Dermatitis -Elicitation : 

Skin M.Yousry 31 Allergic Contact Dermatitis -Elicitation

Pathophysiology of AllergicContact Dermatitis : 

Skin M.Yousry 32 Pathophysiology of AllergicContact Dermatitis Activated T cells, ? Cytokine release ?? adhesion molecules in venules (selectins) ? leukocyte migration from B.V.s to the dermis and epidermis ? edema, ? T cells ? vesicles.

Interference with BarrierBullous Disease : 

Skin M.Yousry 33 Interference with BarrierBullous Disease Moderate Interference Cutaneous function moderately impaired Blisters may occur within the epidermis or between the epidermis and dermis

Separation of epidermis/dermis : 

Skin M.Yousry 34 Separation of epidermis/dermis

Bullous Diseases : 

Skin M.Yousry 35 Bullous Diseases Acquired bullous diseases Genetically determined bullous diseases Reaction pattern blistering diseases

Autoimmune Bullous Diseases : 

Skin M.Yousry 36 Autoimmune Bullous Diseases The acquired bullous diseases are autoimmune diseases where the skin is the target organ. An antibody is directed at an integral molecule in the skin.

Blister Location : 

Skin M.Yousry 37 Blister Location Epidermal blisters -Pemphigus group Subepidermal blisters -Bullous Pemphigoid, -Cicatricial Pemphigoid -Herpes Gestationis – Epidermolysis Bullosa Acquisita (EBA) – Linear IgA Bullous Dermatosis (LABD) – Dermatitis Herpetiformis (DH)

Location of Bullae : 

Skin M.Yousry 38 Location of Bullae

Diagnosis & Diagnostic Procedures : 

Skin M.Yousry 39 Diagnosis & Diagnostic Procedures Skin biopsy for histology Skin biopsy for immunofluorescence Blood specimen for indirect immunofluorescence

Direct immunofluorescence : 

Skin M.Yousry 40 Direct immunofluorescence Detects in-vivo deposition of immunoglobulin, complement, fibrinogen in skin. Frozen sections are incubated with FITC-labeled monospecific antisera (anti-antibody) (IgG, IgM, IgA, C3, fibrinogen). One step procedure

Intraepidermal Bullous Diseases : 

Skin M.Yousry 41 Intraepidermal Bullous Diseases Pemphigus Blistering diseases in which autoantibodies are directed against cell surface of keratinocytes leading to loss of cohesion between the cells (acantholysis).

Pemphigus : 

Skin M.Yousry 42 Pemphigus Major forms -Pemphigus Vulgaris – Pemphigus Foliaceus – Both characterized by loss of cell to cell adhesion (acantholysis) caused by IgG autoantibodies directed against cell surface molecules.

Pemphigus Antibody Deposition : 

Skin M.Yousry 43 Pemphigus Antibody Deposition

Pemphigus Foliaceus : 

Skin M.Yousry 44 Pemphigus Foliaceus Vesicles are superficial and fragile Usually only crust and scale seen May become generalized - exfoliative erythrodemic dermatitis Rare mucous membrane lesions (rare oral lesions)

Pemphigus Foliaceus : 

Skin M.Yousry 45 Pemphigus Foliaceus

Pemphigus Foliaceus : 

Skin M.Yousry 46 Pemphigus Foliaceus

Pemphigus Vulgaris : 

Skin M.Yousry 47 Pemphigus Vulgaris

Pemphigus Vulgaris : 

Skin M.Yousry 48 Pemphigus Vulgaris

Pemphigus Vulgaris : 

Skin M.Yousry 49 Pemphigus Vulgaris Acantholytic Diseas Process Blisters occur just above the basal cell layer. Widespread blisters involving skin and mucous membranes

Pemphigus Vulgaris Histopathology : 

Skin M.Yousry 50 Pemphigus Vulgaris Histopathology


Skin M.Yousry 51 THANK YOU

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