Unit Vocabulary
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1st degree burn - burns in the epidermis layer; it's red without blisters, takes 5-10 days to heal without scarring
2nd degree burn - extends into the dermis layers; it's red with blisters, takes 2-8 weeks with possible scarring
3rd degree burn - extends into the hypodermis layer; it's stiff and white; it takes months to heal with scarring
A
acne - a skin condition originating from factors involving the accessory structures of the skin, such as oil, dead skin, clogged pores, and bacteria; occurs when sebaceous glands are clogged, leading to infection and inflammation of the skin
anagen phase - cells divide rapidly at the root of the hair, pushing the hair shaft up and out
apocrine sweat glands - located in the armpits and genital regions; secrete water, salt, and organic compounds
arrector pili muscle - attached to the hair follicle
B
basal cell carcinoma - a form of cancer that is an uncontrolled growth arising from the basal cells of the epidermis
C
catagen phase - marks a transition from the hair follicle's active growth
cold sore - a viral infection caused by a strain of the herpes virus
collagen fibers - protein of the connective tissue providing strength and cushion
cortex - the second layer making up most of the hair shaft
cuticle - also known as the eponychium, helps anchor the nail body
cuticle - the outermost layer made of shingle-like scales protecting the hair shaft
D
dermis - the inner layer of the skin that is made of dense, irregular connective tissue and located directly beneath the epidermis
E
eccrine sweat glands - produces a hypotonic sweat composed of water, salt, antibodies, metabolic waste, and antimicrobial
eczema - an allergic reaction that manifests as dry, itchy patches of skin that resembles rashes
epidermis - the outside layer of skin that is made of closely packed epithelial cells and is divided into 4-5 sublayers
eumelanin - black/brown pigment color
F
fibroblasts - a cell in connective tissue that produces collagen and other fibers
G
H
hair - dead, keratinized cells
hair bulb - the hair root ends here, a rounded area where the hair matrix is located
hair follicle - tunnel-like segment where strands or hair originate
hair matrix - located in the hair bulb; cells divide to produce new hair
hair papilla - contains the blood vessels to nourish the cells and nerve endings from the dermis; surrounded by the hair bulb
hair root - hair that is anchored by the follicle and lies below the surface of the skin
hair shaft - part of the hair that is not anchored to the follicle
hypodermis - a fatty layer of skin, also known as the subcutaneous layer, that insulates the body and connects the skin to the underlying surface
I
impetigo - a bacterial infection caused by the streptococcus bacteria
integumentary system - composed of the skin and its accessory structures
J
K
keloid scars - scars that are raised and extend beyond the area of the injury
keratin - a protein that provides strength, flexibility, and toughness to the skin
keratinocytes - most cell types of the skin that produce the protein keratin
L
Langerhans cells - cells playing a role in immunity functioning as antigen-presenting cells
lunula - the half-moon shaped white area on a nail caused by a thick layer of epithelium over the nail matrix
M
matrix - the region of the nails where division and nail growth occurs
medulla - the innermost layer of hair
melanin - a protein pigment responsible for giving color to skin and hair
melanocytes - melanin-producing cells located in the bottom layer of the skin's epidermis
melanoma - a cancerous uncontrolled growth of melanocytes typically developing from a mole
melanosomes - spherical organelles; melanin-producing factories that carry the melanin to keratinocytes in the epidermis
Merkel cells - cells of the epidermis involved in the function of touch sensations
merocrine glands - the secretions are excreted by exocytosis through a duct without affecting the cells of the gland
N
nail bed - specialized structure of the epidermis that is found at the tips of fingers and toes
nail body - also known as nail plate, formed on the nail bed and protects the tips of our fingers and toes
nail fold - overlaps the nail on the sides helping to anchor the nail body
nail plate - also known as the nail body, rests on the nail bed
nail root - proximal portion of the nail that is underneath the skin
O
P
papillary layer - supplies nutrients to cells in the epidermis
pheomelanin - provides a red/yellow color
psoriasis - caused from an immunity issue resulting in patchy skin lesions
Q
R
reticular layer - the thickest layer of the dermis made of collagen fibers produced by cells called fibroblasts
rickets - softening and weakening of the bones due to a vitamin D deficiency
ringworm - a fungal infection caused by a yeast strain
S
sebaceous glands - oil glands that release sebum, which is a mixture of lipids; they secrete oil
skin - the largest organ of the body with a surface area of 1-2 square meters and comprising about 15% of total body weight
skin cancer - uncontrolled growth of abnormal skin cells
squamous cell carcinoma - an uncontrolled growth of abnormal cells arising in the squamous cells
stratum basale - deepest layer in the epidermis where cell division occurs producing new cells that migrate up to the surface and are sloughed off
stratum corneum - superficial layer of the epidermis containing keratin-packed dead cells and the cells that produce keratin
stratum granulosum - keratinocytes lose their nuclei as they migrate up to this layer in the epidermis
stratum lucidum - this layer of the epidermis is only present in thick skin
stratum spinosum - contains Langerhans cells and keratinocytes in the epidermis
sweat glands - release sweat as well as wastes and heat; develop from epidermal projections into the dermis
T
telogen phase - the hair follicle is at rest and no new growth occurs
U
V
W
warts - a viral infection of the epidermis