Basics Of Dermatology Flashcards
Skin
Wt-
Area covered -
Total body wt-
Wt- 3-4 kg
Area covered - 1.7m^2
Total body wt- 16% of total body wt
Layers of epidermis
Histology of epidermis
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
Stratified squamous epithelium
Stratum corneum
- rich in
- nucleus
Pathology (2 types)
Rich in keratin protein
Nucleus is absent
Pathology -
1) hyperleratosis- thickening of statum corneum
Eg psoriasis
Lichan planus
2) pankeratosis- presence or retention of nucleus in stratum corneum
Eg psoriasis
Lamellar layer also called
Function
Statum granulosum pathology
Cementosome/ odlandbodies
Produce lipid
Fnx - Barrier fnx of skin
Pathology
1) hypogranulosis- eg psoriasis
- icthyosis vulgaris
2) hypergranulosis- wedge shape
Eg - lichan planus
Absense Flaggrin protein caused which disease
Atopic dermatitis
Icthyosis vulgaris
Stratum spinosum
- rich in
-also know as
-causes which disease
Pathology
Rich in desmosomes
Also Know as prickle cell layer
Pemphigus group of ds
Thickest layer of epidermis
Pathology
1) intracellular- ballooning degeneration
Eg hsv
2) intracellular - spongiosis
Eg - acute eczema
Layers
1) acanthosis
Thickening of stratum spinosum
Eg- psoriasis
Lichan planus
2) acantholysis
Loss of spines
Stratum basal also k/a
Stratum basal+ statum spinosum=
Projection of epidermis into dermis =
Projection of dermis into epidermis=
Stratum germinatum
Malpighian layer
Rete ridges
Dermal papilla
Transition from stratum basal to statum corneum
Shape-
Nucleus -
Keratin-
Water-
Epidermal transit time -
Shape-flattening of cell
Nucleus -absent in stratum corneum
Keratin-increases
Water-decreases ( dehydration)
Epidermal transit time - 28 days ( 4 weeks)
Cells of epidermis - classification
A) keratinocytes
- 95% cell present
- hallmark - keratin intermediate filament
- derived from- ectoderm
B) non- keratinocytes
- langerhan cell
- melanocytes
- Merkel cells
Non keratinocytes
A) langerhan cells
B) malpighians cell
C) Merkel cell
- location
- derived from
-content - function
- marker
-used clinically in diagnosis of
Langerhan cell
It is a dendritic cell
- location - statum spinosum
- derived from bone marrow
-content - birbeck granules (tennis racquet apperance)
- function- antigen presenting cells
- marker- s100, cd1a, cd207 (langrin)
-used clinically in diagnosis of langerhan cell histocytosis
Malpighian cell
It is a dendritic cell
- location- statum basale
- derived from neural crest
-content- melanosomes
- function - production of melanin
- marker- s100, melan A, hmb- 45
-used clinically in diagnosis of melanoma
Merkel cell
- location- statum basale
- derived from ectoderm
-content- neurosecratory granules - function- mechanoceptors( slow adapting, low threshold)
- marker- cytokeratin 20
-used clinically in diagnosis of Merkel cell granuloma
Demoepidermal jnx-
Structure of basement membrane zone-
Demoepidermal jnx- also called basement membrane zone (bmz)
Specialized zone at interphase of dermis and epidermis
Str of basement membrane
- hemidesmosome + keratin intermediate filament
- lamina lucida
- lamina densa
- sublamina densa
Dermis
Types-
Content -
1) papillary dermis( superficial)
- losse connective tissue
- forms 1/10th of the dermis
2) Reticular dermis
- dense connective tissue
- forms 9/10th of the dermis
Content -
•Connective tissue
• cells- macrophages, mast cells, lymphocytes
•ground substance - Glycosaminoglycans (GAG)
•appandages- hairs, glands( swaet, sebaceous), blood vessels, nerves
Components of connective tissue
- collagen( 70%): tensile strength to skin
- elastic fibres
a) elastin- elasticity
b)elastin associated microfibril ( fibrillins, fibulin) : Recoil
Collagen:
• most common type of collagens( skin) - type 1
•2nd mc type of collagen ( skin) - type 3
•distribution of collagen in cartilage - type 2
Hypodermis
Also k/a
Function -
Inflammation of subcutaneous fat-
K/a - pannculus or subcutaneous fat
Function - insulation
- panniculitis
Acantholysis
Def-
K/a
Characterized by-
Targeted by -
- Loss of attachment blw keratinocytes
- k/a acantholytic cell/ tzanck cell( bcoz tzanck smear used in diagnosis)
• circular cell
• prominent nucleus
• perinuclear halo - characterized by defective desmosomes
- targeted by
1- autoimmune processes- pemphigus group
2- infection
• bacterial - bullous impetigo, ssss
• viral- hsv
3- genetic deformity -
Haliey haliey disease
Darier disease
Dyskeratosis
Microabcess
Types
Dyskeratosis - premature abnormal or faulty keratinisation of individual cell
Eg darier disease
Bowen disease
Squamous cell carcinoma
Microabcess- small microscopic collection of cell
A- neutrophillic microabcess
1) Munro micro abscess
Layer- s. Corneum
Eg psoriasis
2) spongiform pustule of kogoj
Layer-s. spinosum
Eg- psoriasis
3) papillary tip microabcess
Dermatitis hepatiformis
Subepidermal bullae
B- eosinophillic microabcess
- pemphigus vegetans
C- atypical lymphocytes
•Pautrier microabcess
• atypical T lymphocytes seen in mycosis fungoides
• mycosis fungoides is known as cutaneous t cell lymphoma