The Integumentary System

Normal skin, Genetic Defects, and Scar Formation

Cross section throughhuman skinKeratin

Stratified squamous epithelium

Dense irregular connective tissue

Cross section through human skin

Pacinian corpuscle (note the onion-like appearance)

Meissner corpuscles located in the dermis

Melanin producing melanocytes

Genetic Abnormalities Associated with Skin

Epidermolysis Bullosa

Fragile Skin, Blistering do toa defect in the adhesionmolecules that keepthe simple squamous epithelium together

Ichthyosis – Scaly fish disorder

Harlequin Type 1 ichthysos

Neurofibromatosis – defect on Chromosome 1. Autoosmaldominant disorder

Incontinentia Pigmenti

X-linked disorder, often fatal in boys, causeshyperpigmentation of theskin, blistering, loss ofmotor function, delayedgrowth, mental impairment

Albinism – A autosomal recessive genetic disorder in which the individualproduces no melanin. Albinism occurs in all species and races

Simplified cross section of a hair

Scar Formation

Normal healing, epithelial cells move to the areaLittle or no fibroblast activity

Mild hypertrophic scarring

Mild keloid formation

Keloid formation

Cesarean section scars then and now

Ritual scarification of the skin for religious or cultural reasons

Scarification as body art / modification

Diabetic ulcerationof the foot, notethe extensortendons of the foot