Ch 6.2- Integumentary Structures Derived from the Epidermis Flashcards
What is the main part of the nail called?
Nail body
What is the name for the cuticle?
Eponychium
Nai bed
The part of the epidermis under the nail body.
Nail matrix
Thickened part of the nail bed just beneath the nail root.
Lunula
White part of the nail close to the eponychium.
Hyponychium
The are of thickened epidermis just under the free edge of the nail.
Pilus
Single hair
What are the three types of hair?
Lanugo, vellus, and terminal hair.
Lanugo hair
the fine hair on new born babies.
Vellus hair
hair found on limbs
Terminal hair
hair on the scalp.
Three zones of hair?
Hair bulb, root, and shaft.
Hair bulb
swelling at the base of hair where it originates in the dermis
Hair papilla
Epithelium at the base of the bulb made of connective tissue with tiny blood vessels and nerves.
Hair root
part of hair extending from the bulb of to the skins surface.
Hair shaft
portion of hair that extends beyond the skins surface.
Hair matrix
Immediately adjacent to the hair papilla where special type of keratinization occurs.
Medulla
Remnant of the soft core of hair matrix. Contains loosely arranged cells and air spaces and contains soft flexible keratin.
Cortex
several layers of cells close to the cells outer surface.
Hair Cuticle
Single layer of cells that coats the hair cortex.
Hair follicle
Oblique tube that surrounds the hair root. Always extends into the dermis and sometimes into the subcutaneous layers.
Two layers of hair follicle
Outer connective tissue root sheath from the dermis, and epithelial root sheath from the epidermis.
Arrector pilli
Thin ribbons of smooth muscle that attach to the hair follicle.
Anagen phase
Phase of hair growth 18 months to 7 years. 80-95% of hair on scalp is made up of this kind of hair.
Catagen phase
Regression period where cell division ceases and follicle undergoes involution. 3-4 weeks.
Telogen phase
Resting phase when hair is shed. After three to four months, the cells in the hair bulb start regrowing and follicles re-enter the anlagen phase.
Alopecia areata
Spot boldness
What are the two types of sweat glands?
Merocrine (Eccrine) and apocrine. Both have coiled tubular secretory portion in the dermis and ducts that bring secretion to the surface in merocrine and to the hair follicle in apocrine.
Merocrine sweat glands
Clear sweat secretions through exocytosis.
Main purpose is thermoregulation
What method do eccrine glands use to excrete substances?
use exocytosis
Apocrine sweat glands
Release secretions onto hair follicles in the axillae, nipple, pubic, and anal regions. Also done through exocytosis. Secretory portion of gland has much larger lumen than merocrine sweat glands. Secretions are viscous and cloudy and contain proteins and lipids that produce a distinct and noticeable odor when acted on by bacteria. Become active at puberty. Named because people used to think that it delivered its contents by pinching them off along with a portion of the apical surface of the cell.
Sebacious Glands
Holocrine glands (release contents through cell rupture-causing cell death) Produce oily waxy section called sebum. Discharged onto the hair follicle and onto hair itself. Bacterialcidal qualities. Multiple can open onto one hair follicle.
Ceruminous glands
Modified apocrine sweat glands in the external acoustic meatus of ear. Form cerumen (ear wax).
