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Epithelial Layer

Functions of Skin

  1. Barrier Against Microbes
  2. Barrier against water PAssage

Layers of Skin

Layers of Skin

Mnemonics

Can't Let's Get Sun Burn > Can't - Corneum = anucleated,keratinized > Let's - Lucidum = only in thick skin > Get - Granulosum = lipids for water barrier keratin,Keroto-hyaline granules(Basophilic) > Sun - Spinosum(like spines) = attached with others with Desmosomes > Burn - Basale = Stemcells ,hemidesmosomes with loose Connective tissu.

graph LR
    Y[Epidermis] ==> Y1[Epithelial layer];
    Y2[Dermis] ==> Y2a[Connective Tissue layer];
    X{layers of Skin} ==> X1[Epidermis];
    X1 ==> X1a[ 5 layers];
    X ==> X2[Dermis];
    X2 ==>|be:octicons-arrow-down-24: Statum Basale| X2a[Papillary layer];
    X2 ==> X2b[Reticular Layer];
    X ==> X3[Hypodermis];
    X3 ==> X31[Adipose Loose CNT];
    X1a ==> X1a1[Stratum Basale];
    X1a ==> X1a2[Stratum Spinosum];
    X1a2 ==>|Cytoplasmic Process of Desmosomes attaching cells | X1a2a[Barrier against Microbes];    
    X1a ==> X1a3[Stratum Granulosum];
    X1a3 ==>|contains| X1a3a[Keratin Precursor Proteins 
    Kertohyaline Protein = The Basophilic color];
    X1a3 ==>|produce Lipids| X1a3a[Covers the Statum Cornuem = Impermeable to Water];
    X1a ==> X1a4[Stratum lucidum];
    X1a4 ==>|only present in thick Skin| X1a41[Disapperance of Nucelus and Organelle's and filled with lipid]
    X1a ==> X1a5[Stratum Corneum];
    X1a5 ==> X1a5a[Anucelated rich in Keratin, covered by Lipids ,forms water barrier];

Burns

Loss of Skin layers 

graph LR 
    X{loss of Statum Corneum} ==>|loss of water barrier| X1[dehydration by evaporation etc…];
    Y{loss of Statum Spinosum} ==>|loss of Immunological Barrier| Y1[Infection];

Think skin vs Thin Skin

|Characteristics|Thick Skin|Thin skin| |—|—|—| |Layers |1.Multiple Stratum Granulosum = for Keratin synthesis,Multiple Stratum Corneum = For Thickness against Mechanical stress |Few layers of Corneum = very stress| |||One layer of Granulosum = no need for lots of Keratin| |Location|Palms and Soles|All other region|

Immigrants to Epidermis

  1. Melanocytes = produce melanin
  2. Langrehens = macrophages

Immigrants Of Epidermis

Melanocytes

graph TD
    X[Melanocytes] ==>|migrates to the  Stratum Basale| X1[produce Melanin pigment];
    X1 ==>|stored in oragnales called Melanosomes| X1a[Transferred via extensions ];
    X1a ==> X1b[eaten by Keratinocytes from Stratum Basale daughter cells];
    X1b ==> X1c[Melanin Pigments Protects from UV light];

Melanome

Normally melonocytes doesn't store pigments as they give to keratinocytes

    IN melanoma
==> irregular growth of melanocytes present outside of Stratum Basale with pigment of melanin within themselves.

Albinism

In this hereditary condition, premelanosomes are Produced by melanocytes 

graph TD
    subgraph Normally
    X[Tyrosine] ==>|tyrosinase| X1[DOPA];
    X1 ==> X2[Melanin];
    end
    subgraph Albinism
    Y[Tyrosine] ==>|<del>Tyrosinase</del>|Y1[<del>DOPA</del>];
    Y1 ==> y2[<del>Mealinin</del>]
    end

Langrehens

  1. Location - at Stratum Spinosum
  2. Function > Langrehens + Spinosum = Microbial Barrie's > Langrehens are Macrophages => Which phagocytosis the Microbes coming to Stratum Spinosum ==> Then travel to lymph node for Activation of Lymphocytes > Stratum Spinosum = Cells Connected with Desmosomes