Chapter 5: Integumentary System Part 2 Flashcards
Hair production
Begins at the base of the hair follicle, deep in the dermis.
Hair papilla contains capillaries and nerves
Hair bulb and papilla produces a hair matrix.
A layer of dividing cells, produces hair structure and pushes hair out of the skin.
hair matrix
layer of epithelial cells at the base of the hair bulb in contact with the hair papilla
Medulla
Is the center of the hair that contains soft keratin
Cortex
Contain layers of hard keratin (surrounding the medulla)
Cuticle
Thin and tough and contains hard keratin. (surrounding cortex)
External root sheath
Extends from the skin surface to the hair matrix.
New hair growth cycle
The follicle becomes active
Produces new hair
Club hair is shed
Club hair
not growing
Attached to an inactive follicle.
Hair color- where are melanocytes located?
Produced by melanocytes in the HAIR PAPILLA (Hair matrix)
Hair color is determined by genes
Sebaceous Glands
Oil glands
They are holocine glands.
They discharge an oily lipid secretion into hair follicles by the rupture of secretory cells.
Gland cells produce large quantities of sebum (lipids)
Sebum
Oily lipids
Protect and lubricates the epidermis
Inhibits bacteria
How is the secretions of sebum stimulated?
It is stimulated by hormones which are inactive in childhood and activated in puberty.
Seborrhea
Fast growing sebum
Over-active sebaceous glandsW
Whitehead
Sebaceous gland duct blocked by accumulated sebum
Blackhead
Sebum in the whitehead dries up and is oxidized.
Acne
Inflammation of the sebaceous gland
Accompanied by pimples
Secondary to bacterial infection.
exocrine gland
Empty though ducts to the epithelial surface.