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What is skin
It is the largest organ of the body
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Skin is our only barrier against the
Environment
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What should healthy skin be
Slightly moist, soft, and flexible
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The skin of the scalp is constructed similarly the skin elsewhere on the body but the scalp has what to accommodate the longer hair of the head
larger and deeper hair follicles
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What is vellus or lanugo hair
It is short fine and downy hair it is commonly found on infants as well as on adults but it is on areas usually considered hairless except the palms of the hands and the soles of the feet
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What is terminal hair
Long hair found on the scalp legs arms and body it is coarser than vellus hair and with the exception of Grey is almost always pigmented
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a mature strand of human hair is divided into how many parts
2
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What are the names that the human hair is divided into
Hair Root and hair shaft
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What are the structures of the hair root
The follicle, bulb, and dermal papilla
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What is the follicle
It is a tube like pockets in the skin or scalp containing the hair root. It surrounds the dermal papilla. Hair follicles are distributed all over the body, with the exception of the palms and soles of the feet
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What is the bulb
The lowest area of the hair strand it is a thickened Club shaped structure that forms the lower part of the hair root. The lower part of the bold fits over and covers
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What is the dermal papilla
A small cone shaped area located at the base of the follicle it contains the blood and nerve supply that provides the nutrients needed for hair growth
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What are the structures associated with hair follicles
Arrector pili and sebaceous glands
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What is the arrector pili
a tiny, involuntary muscle in the base of the hair follicle; strong emotions or cold cause it to contract, which makes the hair stand up straight, resulting in "goosebumps"
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What is the sebaceous glands
the oil glands of the skin connected to the hair follicles; the secrete an oily substance called sebum which lubricates the hair and skin
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What oily substance does the sebaceous glands secrete that lubricates the hair and skin
sebum
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What are the growth patters created by hair follicles
hair stream- 
whorl- 
cowlick- 
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What is a hair stream
hair that flows in the same direction. Two streams that flow in opposite directions form a natural part in the hair
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What is a whorl
hair that forms a circular pattern, usually on the crown
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What is a cowlick
a tuft of hair that stands straight up
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What are the growth cycles of the hair
Anagen, Catagen, Telogen
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What is anagen
It is the growth phase when new hair is produced. The average growth of healthy hair is about an inch per month. At any one time, about 90% of scalp hair grows in this phase, which generally last from 3-5 yrs. The longer the anagen cycle is, the longer the hair can grow.
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What is catagen
it is the transitional phase after growth during which, the follicle canal shrinks and detaches from the dermal papilla; the hair bulb disappears and the shrunken root end forms a rounded club. At any one time, less than 1% of scalp hair is in this stage, which is very short and lasts from 1-2 weeks
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What is telogen
it is the resting phase and the final phase in the hair cycle, which lasts until the fully grown hair is either shed or is pushed out during the next anagen phase. At any one time, about 10% of the hair is in the is phase which lasts about 3-6 months
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On average how long does the entire growth cycle repeat itself
once every 4 to 5 years
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