1
What are the 3 accessory organs of the skin?
hair, nails, cutaneous glands
what is fine, unpigmented hair that appears on the fetus in the last 3 months of development?
downy hair/lanugo
the greatest diameters of hair are in the ___ hairs of the eyelashes, eyebrows, and nostrils
guard
the portion of a hair above the skin
shaft
The only living cells of a hair are in and near the __
bulb
the stratum corneum of the skin is made of what kind of keratin?
hair and nails are composed of what kind of keratin?
pliable, soft
Hard
the portion of hair beneath the surface
root
what is the fine, pale hair that replaces the lanugo?
vellus
constitutes 2/3 of hair on women, 1/10th hair of men, and all hair of children except for the eyebrows, eyelashes, and hair of scalp
free edge
in response to cold, fear, touch, etc, the SNS stimulates the arrector muscle to contract, making the hair stand on end and wrinkling the skin
piloerection
a slender filament of keratinized cells that grow from a follicle
pilus/hair
a layer of hair: a core of loosely arranged cells and air spaces
medulla
prominent in thick hairs like eyebrows, but narrower in the hairs of medium thickness and absent from the thinnest hairs of the scalp and elsewhere
the condition in which hair is lost unevenly across the scalp rather than thinning uniformly
pattern baldness (androgenic alopecia)
what is the longer, coarser, and usually more heavily pigmented hair?
terminal
forms the eyebrows and eyelashes and covers the scalp
after puberty, it also forms the axillary and pubic hair, all facial hair, and some on trunk and limbs
the visible attached part of the nail
nail body
what is the oblique tube in the skin that the hair grows out of?
the root penetrates deeply into the dermis or hypodermis and ends with this dilation
bulb
the fingertips become swollen or clubbed in response to what?
long term hypoxemia- deficiency of oxygen in the blood stemming from conditions such as congential heart defects and emphysema
flat or concave (spoonlike) nails are a result of
dietary deficiences
Thinning of the hair/baldness
alopecia
differences in apparent hairiness are due to mainly differences in ___ & ___?
texture and pigmentation
what are the 2 principle layers of a follicle?
epithelial root sheath: extension of the epidermis, consisting of stratified squamous epithelium and lies immediately adjacent to the hair root
connective tissue root sheath: derived from the dermis and composed of collagenous connective tissue, surrounds epithelial sheath and is denser than the adjacent dermis
the epidermis of the nail bed
hyponychium
the ___ ___ extends proxmially under the overlying skin
nail root
a narrow zone of dead skin
cuticle/eponychium