| • At the very center of the hair follicle is the hair shaft.
• Surrounding it are the inner and outer hair sheath.
• The two sebaceous glands are attached to the hair follicle above the erector pili muscle.
• In this appearance, the sebaceous gland can be seen to be composed of an outer layer of cuboidal dark-staining cells and centrally situated numerous lighter-staining cells with abundant cytoplasm and a pyknotic nucleus. |
| Normal hair |
| Etiology |
•N/A |
| Pathogenesis |
•N/A |
| Epidemiology |
•N/A |
| Clinical |
•N/A |
| General Gross Description |
•The entire surface of the body is covered with hair,
with the exception of the palms and soles, the sides of
the feet, the inner surfaces of the labia and the glans
penis and the inner surface of the prepuce.
•Most of the hairs are short and colorless and barely
visible.
•Hair over the scalp can be > 1 meter long. |
| General Micro Description |
•A normal hair is composed of a shaft and hair bulb.
•The bulb is composed of a dermal papilla covered by a
single layer of basal cells that generates the hair
shaft.
•The center most cells are the basal layer covering the
dermal papilla which give rise to the medulla of the hair.
• Cells immediately surrounding this give rise to the
cortex
•Further to the periphery, are the cells give rise to the
hard cuticle of the hair.
•In addition, the hair shaft has a internal root sheath and an external root sheath. |
| Reference |
| Basic Histology: Text & Atlas, 10th Ed., 2003, Ch. 18.
|
