Dermatology Flashcards
What are the layers of epithelium (from surface to basal)
What are the 3 layers in skin?
Epidermis: basement membrane/dermoepidermal junction
Dermis
Subcutaneous tissue/subcutis
What is the function of the epidermis?
What is common disease of epidermis?
- SJS
- Toxic epidermoid necrolysis
- Eyrthroderma
What are the layers of basement membrane/dermoepidermal junction?
What is function of DEJ?
-Basal cell membrane-Lamina lucida (20-40nm)-Lamina densa (30-60nm)-Sub-lamina densa + Anchoring fibrils
Function of DEJ
-Mechanical support
-Adhesion
-Growth of basal layers
What are common diseases of DEJ?
Hereditary: junctional and dystrophic epidermolysis bullosa (complex inherited idseases p/w friable skin, bullous lesion, often w/scaring)
Acquired: bullous pemphigoid: antihemidesmosomal ab produced and appear to induce inflammation and subseqent damage of hemidesmosomes, causing blsiter to develop between cells and BM. Blistering occurs secondary to disruption of structures of BM and dermis
What are the layers of the dermis? (from surface to basal)
Functions of dermis?
Layers
Papillary dermis: finger like projection in contact with Rete ridges
Reticular dermis: dermal plexus (dermis is rich in blood supply), dense connective tissue)
- Thermoregulation -Through control of cutaneous blood flow and sweating, achieved by dermal vessels and eccrine sweat glands 2.Mechanical protection
-Primarily by Collagen and Hyaluronic acid - Innervation of the skin
- -Responsible for cutaneous sensation
What is the pilosebacous unit composed of, what common diseases affecting pilosebaceous unit?
Consists of hair follicle, sebaceous gland, hair
Common disease affecting pilosebaceous unit: acnes
What is eccrine glands
What disease affects eccrine glands?
Eccrine glands -Watery sweat glands-Millions of eccrine glands in human body-Widely distributed all over body esp. Palms, Soles
Secretory activities-Ultra-filtrate of plasma-like fluid-Hypotonic sweat
Common diseases affecting Eccrine glands-Cystic Fibrosis: Defective ductal Na reabsorption
What are the structural components of nail?
What are barrier defects in skin?
What complications?
What is the pathogenesis of defective stratum corneum?
What is the disease of allergen barrier in skin?
What pathophysiology and gene involved?
-Aetiology: Filaggrin gene mutation; House dust mites, feathers-
Pathophysiology: *Lack of Ceramides (Sphingolipids) (common lipid in cells)
*Trans-epidermal water loss increase → Skin cracks → Allergen enter → Epi-cutaneous sensitisation by allergies
What is the classical and alternative pathway?
C3a,4a,5a are anaphylatoxin (vasodilation and vascular permeability)
C3b: opsoniziation of bacteria (marking) + induce phagocytosis
C5a: anaphylatoxin (mast cell release histamine); neutrophil chemotaxis
C5b + C6-9: MAC –> makes pores in cell membrane –> osmotic lysis
What is the lectin pathway>
(Microbial carbohydrates) *Lectin-Mannose:-C2 → C2a + C2b-C4 → C4a + C4b
What is antimicrobial peptides on skin
What disease associated with increased expression?
-Secreted from epidermis-e.g. Human beta-defensins (HBD-1 to HBD-4), Dermocidine-Anti-bacterial/ viral/ mycotic properties
-Psoriasis * Increased expression of HBD-2 *Less bacterial infection observed in Psoriasis patients
What is cells involved with adaptive immunity?
What is erythematous?
What are common erythematous lesions?
-Blanchable skin redness due to vasodilatation (+/- inflammation) Common Erythematous lesions
-Atopic Dermatitis
-Psoriasis
-Skin infections
What is violaceous
What are common violaceous lesions
-Purplish-Lichenoid eruption *Lichen planus, Rheumatological, Lichenoid drug eruption *Graft-versus-host disease of skin Common Violaceous lesions
-Petechiae
-Purpura
What are hyperpigmented lesions and common examples?
What are hypopigmented lesions and common examples?
What are skin diseases with well defined borders?
Ill defined borders
Well defined borders
Psoriasis
Tinea corporis
Vitiligo
Ill defined borders
* Atopic dermatitis
* Viral exanthema
* Drug eruption/exanthema
What are common causes for flat lesions: macule and patch?
What are common causes for raised lesions?
Papule
Plaques
Common hweals
Common nodules
Common skin tumors