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Identify the layers of the epidermis
stratum germinativum, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
Dandruff is caused by excessive shedding of cells from the outer layer of skin in the scalp. This, dandruff, is composed of cells from which epidermal layer?
A splinter that penetrates to the third layer of the epidermis of the palm is lodged in which layer?
The stratum granulosum
Why does swimming in fresh water for an extended period cause epidermal swelling?
Fresh water is hypotonic in respect to skin cells, so water moves into the cells by osmosis, causing them to swell
Some criminals sand the tips of their fingers so as not to leave recognizable fingerprints. WOuld this practice permanently remove fingerprints? Why or why not?
No. The ridges of fingerprints are formed in layers of the skin that are constantly regenerated, so these ridges will eventually reappear. The pattern of the ridges is determined by the arrangement of the tissue on the dermis, which is not effected by sanding.
Why does exposure to sunlight or sunlamps darken skin?
When exposed to the UV radiation in sunlight or sunlamps, melanocytes in the epidermis and dermis synthesize the pigment melanin, darkening the skin
why does the skin of a fair-skinned person appear red during exercise and hot weather?
When skin gets warm, arriving oxygenated blood is diverted to the superficial dermis for the purpose of eliminating heat. The oxygenated blood imparts a reddish coloration to the skin
Explain the relationship between sunlight exposure and vitamin D3 synthesis
In the presence of UV radiation in sunlight, epidermal cells in the stratum spinosum and stratum germinative convert a cholesterol related steroid into cholecalciferol, also known as vitamin d3
Name the sources of epidermal growth factor in the body
salivary glands and duodenal glands produce epidermal growth (EGF)
Identify some roles of EGF pertaining to the epidermis
promotes the divisions of germinative cells in the stratum germinativum and the stratum spinosum, accelerates the production of keratin in differentiating keratinocytes, stimulates epidermal development and epidermal repair after injury, and stimulates synthetic activity and secretion of epithelial cells
describe the location of the dermis
A connective tissue layer that lies between the epidermis and the hypodermis
Where are the capillaries and the sensory neurons that supply the epidermis located?
In the papillary layer of the dermis
What accounts for the ability of the dermis to undergo repeated stretching?
The presence of elastic fibers and the resilience of skin turgor allow the dermis to undergo repeated cycles of stretching and recoil returning to its original shape
list the two terms for the tissue that connects the dermis to underlying tissues
hypodermis or subcutaneous layer
A layer of loose connective tissue below the dermis; it is also called the subcutaneous layer or superficial fascia. It is not considered an actual part of the integument, but it is important in stabilizing the potion of the skin in relation to underlying tissues
identify sacral functions of subcutaneous fat
provides insulation to help reduce heat loss, serves as an energy reserve, acts as a shock absorber for the body
functions of the dermis
thermoregulation, sensory reception, supports epidermis, nourishes epidermis
functions of accessory structures
produce secretions, protect epidermal surfaces, provide sensations
4 layers of the epidermis(deepest to surface)
stratum germinativum, stratum spinosum, stratum granulosum, and stratum corneum
the reticular layer of the dermis consists of
dense, irregular connective tissue, and collagen fibers
the layers of the epidermis, beginning with the deepest layer and proceeding outwardly, include the stratum:
germinativum, spinosum, granulosum, corneum
epidermal cells in the strata spinosum and germinativum function as a chemical factory in that they can convert:
steroid precursors to vitamin D when exposed to sunlight
that basic factors interacting to produce skin color are:
circulatory supply and pigment concentration and composition
skin exposure to small amounts of UV radiation serves to:
convert a steroid related to cholesterol into Vitamin D
excessive exposure of the skin to UV radiation may cause redness, edema, blisters, and pain. The presence of blisters classifies the burn as:
When exposed to UV radiation, epidermal cells in the stratum germinativum convert a cholesterol-related steroid into:
the hormone essential for the normal absorption of calcium and phosphorus by the small intestine is:
epidermal growth factor EF has widespread effects on epithelia tissue in that it:
promotes the division of germinative cells, accelerates the production of keratin, and stimulates epidermal development and repair
Special smooth muscles in the dermis that, when contracted, produce "goose bumps" are called:
the reason the subcutaneous layer is useful for subcutaneous injection by hypodermic needle is that it has a:
limited number of capillaries and no vital organs
an important function of the subcutaneous layer is to:
stabilize the position of the skin in relation to underlying tissues
In areas where the epidermis is thick, the cells are flattened, densely packed, and filled with eleidin. This layer is called the:
Mobile macrophages that are a part of the immune system and found scattered among the deeper cells of the epidermis are called:
Bone development is abnormal and bone maintenance is inadequate if there is a dietary deficiency or lack of skin production of:
the subcutaneous layer, or hypodermic, is extensively interwoven with the connective tissue fibers of the:
a bundle of smooth muscle cells, which extends from the papillary layer of the dermis to the connective tissue sheath surrounding the hair follicle, is the:
Hair develops from a group of epidermal cells at the base of a tube-like depression called a:
variations in hair color reflect differences in structure and variations in the pigment produced by:
The glands in the skin that become active when the body temperature rises above normal are the:
If the body temperature drops below normal, heat is conserved by a ___ in the diameter of dermal blood vessels
during a sustained reduction in circulatory supply, the skin takes on a blush coloration called:
an essential part of the healing process during which the edges of a wound are pulled closer together is called:
the system that stimulates contraction of arrestor pili muscles to elevate hairs of the integument is the ___ system
when the body temperature becomes abnormally high, thermoregulatory homeostasis is maintained by:
an increase in sweat gland activity and blood flow to the skin
the immediate response by the skin to an injury is:
bleeding occurs and mast cells trigger an inflammatory response
the practical limit to the healing process of the skin is the formation of inflexible, fibrous, noncellular:
sagging and wrinkling of the integument occurs from:
a decrease in the elastic fibrous network of the dermis
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