Flashcards in Lesson 1 notes Deck (42)
What is the surface area of skin?
3000 square inches
What is the thickness of skin?
0.5 to 3 mm
How many cells are contained in one square inch of skin?
3 million cells
What are the functions of skin?
Protect against infection, desiccation, harmful light rays
Maintain body temp
Receive stimuli from environment
Stores chemical compounds
Excretes waste products
Synthesizes vitamin D
Name the thinner outer layer of the skin.
How many layers comprise the epidermis?
4 (palms of hands and feet have 5)
Which layers of the epidermis regenerate the cells of the epidermis?
What is the waterproofing protein that forms in cells as they move towards the surface of the epidermis?
What is the outermost layer of the epidermis?
How often is an epidermal cell shed and regenerated?
How many rows of cells are in the outermost layer of the epidermis?
25 to 30 rows
What are epidermal cells called?
What other cells are found in the epidermis and are protective?
melanocytes and langerhans cells
What layer of skin is deep to the epidermis?
What does the dermis contain?
blood vessels, nerves, glands, hair follicles
What are the three appendages of the skin?
What is the soft hair that covers the body?
What do appendages develop from?
What is the coarse hair that develops at puberty?
terminal also includes hair on scalp and eyebrows
What are the three parts of a hair?
What layer of the skin creates a hair follicle?
What structures are associated with hair follicles?
arrector pili muscles
What glands are associated with the skin?
What are the two types of sweat glands?
apocrine - develop at puberty, located in the axilla, pubic region, and breast areolae.
eccrine - distributed throughout the skin
What is the function of a sebaceous gland?
secrete sebum (oil) which protects the hair and skin from becoming too dry
What are the parts of the nail?
lunula (white area at proximal end)
cuticle (epidermis around the nail)
nail bed (epidermis under the nail)
What three things determine skin color?
Blood in the Capillaries
What is a freckle?
Melanin that forms in patches
How does UV radiation affect melanocytes?
It increases enzymatic activity which produces more melanin. Eventually, epidermal cells take up the melanin by phagocytosis and tanning has occurred.