The skin has up to how many layers of ectodermal tissue
guarding muscles, bones, ligaments and internal organs?
A: Seven.
Human skin is similar to most of the other what?
A: Mammals' skin, and it is very similar to pig skin.
Though nearly all human skin is covered with hair
follicles, it can appear what?
A: Hairless.
What are two general types of skin?
A: Hairy and glabrous skin (hairless).
The adjective cutaneous literally means what?
A: "Of the skin" (from Latin cutis, skin).
Because it interfaces with the environment, skin plays
an important immunity role in protecting the body against what?
A: Pathogens and excessive water loss.
What are its other functions?
A: Insulation, temperature regulation, sensation, synthesis of
vitamin D,
and the protection of vitamin B folates.
How does severely damaged skin try to heal?
A: By forming scar tissue.
Skin provides a rich and diverse habitat for what?
A: Bacteria.
Human skin shares anatomical, physiological,
biochemical and immunological properties with other mammalian lines,
especially what?
A: Pig skin.
Pig skin shares similar epidermal and dermal what?
A: Thickness ratios to human skin.
Pig and human skin share what similar patterns?
A: Hair follicle and blood vessel.
Skin has mesodermal cells, pigmentation, such as
melanin provided by melanocytes, which do what?
A: Absorb some of the potentially dangerous ultraviolet radiation (UV) in
sunlight.
It also contains DNA repair enzymes that help do what?
A: Reverse UV damage.
One form predominantly produced by UV light, malignant
melanoma, is particularly invasive, causing it to do what?
A: To spread quickly, and can often be deadly.
In terms of surface area, the skin is the second
largest what?
How big in surface area is the skin for the average
adult human?
A: The skin has a surface area of from 1.5–2.0 square meters (16–22 sq ft).
The thickness of the skin varies considerably over all
parts of the body, and between men and women and whom?
A: The young and the old.
One average square inch (6.5 cm2) of skin holds what?
A: 650 sweat glands, 20 blood vessels, 60,000 melanocytes, and more than
1,000 nerve endings.
Skin is composed of what three primary layers?
A: The epidermis, the dermis and the hypodermis.
Epidermis, "epi" coming from the Greek meaning "over"
or "upon", is what?
A: The outermost layer of the skin.
It forms the waterproof, protective wrap over the
body's surface which also serves as a barrier to what?
A: Infection.
The epidermis contains no what?
A: Blood vessels.
Cells in the deepest layers are nourished almost
exclusively by diffused oxygen from what?
A: The surrounding air and to a far lesser degree by blood capillaries
extending to the outer layers of the dermis.