The Integumentary System Normal skin, Genetic Defects, and Scar Formation

Cross section through human skin Keratin 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 to a defect in the adhesion molecules that keep the simple squamous epithelium together

Ichthyosis – Scaly fish disorder Harlequin Type 1 ichthysos

Neurofibromatosis – defect on Chromosome 1. Autoosmal dominant disorder

Incontinentia Pigmenti X-linked disorder, often fatal in boys, causes hyperpigmentation of the skin, blistering, loss of motor function, delayed growth, mental impairment

Albinism – A autosomal recessive genetic disorder in which the individual produces 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 activityNormal 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 ulceration of the foot, note the extensor tendons of the foot