Skin
Tissues

Skin is the outer covering of the body.

Skin is composed of three primary layers:

• the epidermis, which provides waterproofing and serves as a barrier to infection
• the dermis, which serves as a location for the appendages of skin
• the hypodermis (subcutaneous adipose layer).

Skin layers

Epidermis

• STRATUM CORNEUM
• STRATUM LUCIDUM
• STRATUM GRANULOSUM
• STRATUM SPINOSUM
• STRATUM BASALE

Normal skin - low power

Normal skin - high power

Oral mucosa

Leprosy

Psoriasis

Epidermolytic Hyperkeratosis

Herpes simplex

Oral leukoplakia

Dermis

Hypodermis

Epidermal Barrier

The skin is an effective barrier against:

• environmental parasites penetration
• environmental chemicals
• environmental physicals agents (UV)
• water evaporation

The molecular components of the barrier are:

• protein intercellular junctions
• lipids
• melanin

Activators of the nuclear hormone receptors PPARalpha and FXR accelerate the development of the fetal epidermal permeability barrier. 1997

E-Cadherin in embrio and newborn

Tra le proteine che costituiscono il Desmosoma vi sono:

• Desmoplachine I, II :glicoproteine associate alle placche.
• Desmoclamina e Cheratocalmina : formano ponti tra proteine della placca e filamenti intermedi
• Desmogleine e Desmocoline : Caderine, glicoproteine integrali di membrana che stabiliscono adesioni intercellulari nella regione delle giunzioni.

Skin Pigmentation

It ismainly dependent on melanin synthesis by melanocytes

Hyperpigmentation caused by hyperthyroidism: differences from the pigmentation of Addison's disease. 1999

Artificial Skin

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pelle_sintetica.jpg	gp	2008-09-01