CH 5 Flashcards
Nails
thin plates consisting of layers of dead stratum corneum cells with hard keratin
Nail body
the visible part of the nail
Nail Root
Part of the nail covered in skin
How do nails grow?
Distally
Nail Fold
Holds the lateral and proximal edges of the nail in place
Eponychium (cuticle)
stratum corneum from the nail fold that extends onto the nail body
Nail matrix
- thick ET with a stratum basale (location of nail tissue formation)
- produces most of the nail
Nail bed
the location where the nail attaches, distal to the nail matrix
Lunula
part of the nail matrix visible through the nail body
What results in the growth of the nail?
the production of cells within the nail matrix
Do nails grow continually?
Yes, unlike hair
The average rate of nail growth?
0.5-1.2 mm per day
T/F: Nails have a resting stage
False, nails have NO resting stage
T/F: Fingernails have a greater growth rate than toenails?
True
Integumentary System: Protection: Skin
- protects underlying structures from abrasion
- prevents entry of microorganisms
- melanin absorbs UV light/ protects underlying structures
- lipids act as a barrier to reduce water loss
Integumentary System: Protection: Nails
- protect the ends of the fingers and toes from damage
- may be used in defense
Integumentary System: Protection: Hair
- hair on scalp acts as a heat insulator and protects against UV light/abrasion
- eyebrows keep sweat out of eyes
- eyelashes protect the eyes from foreign objects
- hair in nose/ears prevents dust and materials from interesting
Integumentary System: Other Functions: Sensation:
-skin contains sensory receptors for: heat, cold, touch, pressure, pain
Integumentary System: Other Functions: Vitamin D Production
- UV light stimulates the production molecule in the skin that is modified into vitamin D
- Vitamin D increases Calcium uptake in the intestines
Integumentary System: Other Functions: Temperature Regulation
- controls heat loss from the body and dilation and constriction of blood vessels
- sweat evaporates and lowers body temperature
Integumentary System: Other Functions: Excretion
- minor function
- sweat glands remove small amounts of waste products (water, salt, urea, uric acid, ammonia)
1st step in temperature regulation:
blood vessel dilation results in increased blood flow toward the surface of the skin
2nd step in temperature regulation
increased blood flow beneath the epidermis results in increased heat loss
3rd step in temperature regulation
blood vessel constriction results in decreased blood flow toward the surface of the skin