Chapter 5 Flashcards
Define acne
skin condition due to infected sebaceous glands
Define albinism
genetic disorder that affects the skin, in which there is no melanin production
Define anagen
active phase of the hair growth cycle
Define apocrine sweat gland
type of sweat gland that is associated with hair follicles in the armpits and genital regions
Define arrector pili
smooth muscle that is activated in response to external stimuli that pull on hair follicles and make the hair “stand up”
Define basal cell
type of stem cell found in the stratum basale and in the hair matrix that continually undergoes cell division, producing the keratinocytes of the epidermis
Define basal cell carcinoma
cancer that originates from basal cells in the epidermis of the skin
Define bedsore
sore of the skin that develops when regions of the body start necrotizing due to constant pressure and lack off blood supply; also called decubitis ulcers
Define callus
thickened area of skin that arises due to constant abrasion
Define catagen
transitional phase marking the end of the anagen phase of the hair growth cycle
Define corn
type of callus that is named for its shape and the elliptical motion of the abrasive force
Define cortex
in hair, the second or middle layer of kertinocytes originating from the hair matrix, as seen in cross-section of the hair bulb
Define cuticle
in hair, the outer most layer of kerantinocytes originating from the hair matrix, as seen in a cross-section of their hair bulb `
Define dermal papilla
extension off the papillary layer of the dermis that increases surface contact between the epidermis and dermis
Define dermis
layer of skin between the epidermis and hypodermis, composed mainly of connective tissue and containing blood vessels, hair follicles, sweat glands and other structures
Define demosome
structure that forms an impermeable junction between cells
Define eccrine sweat gland
type of sweat gland that is common throughout the skin surface, it produces a hypotonic sweat for thermoregulation
Define eczema
skin condition due to an allergic reaction which resembles a rash
Define elastin fibers
fibers made of the protein elastin that increase the elasticity of the dermis
Define eleiden
clear protein-bound lipid found in the stratum lucidum that is derived from keratohyalin and helps to prevent water loss
Define epidermis
outermost tissue layer of the skin
Define epoychium
nail fold that meets the proximal end off the nail body, also called the cuticle
Define external root sheath
outer layer of the hair follicle that is an extension off the epidermis, which encloses the hair root
Define first-degree burn
superficial burn that injure only the epidermis
Define fourth degree burn
burn in which full thickness off the skin and underlying muscle and bone is damaged
Define glassy membrane
layer of connective tissue that surrounds the base of the hair follicle, connecting it to the dermis
Define hair
kerantinous filament growing out of the epidermis
Define hair bulb
structure at the base of the hair root that surrounds the dermal papilla
Define hair follicle
cavity of sac from which hair originates
Define hair matrix
layer of basal cells from which a strand of hair grows
Define hair papilla
mas of connective tissue, blood capillaries and nerve endings at the base of the hair follicle
Define hair root
part of hair that is below the epidermis anchored to the follicle
Define hair shaft
part o the hair that is above the epidermis but is not anchored to the follicle
Define hypodermis
connective tissue connecting the integument to the underlying bone and muscle
Define hyponychium
thickened layer of stratum corneum that lies below free edge of the nail
Define integumentary system
skin and its accessory structures
Define internal root sheath
innermost layer of keratinocytes in the hair follicle that surround the hair root up to the hair shaft
Define keloid
type of scar that layers raise above the skin surface
Define keratin
type of structural protein that gives skin, hair, and nails it hard, water resistant properties
Define kertinocyte
cell that produces keratin and is the most predominant type of cell found in the epidermis
Define keratohyalin
granulated protein found in the stratum granulosum
Define Langerhans cell
specialized dendritic cell found in the stratum spinosum that functions as a macrophage
Define lunula
basal part of the nail body that consists of a crescent-shaped layer of thick epithelium
Define medulla
in hair, the innermost layer of keratinocytes originating from the hair matrix
Define Meissner corpuscle
receptor in the skin that responds to light touch
Define melanin
pigment that determines the color of hair and skin
Define melanocyte
cell found in the stratum basale of the epidermis that produces the pigment melanin
Define melanoma
type of skin cancer that originates from the melanocytes of the skin
Define melansome
intercellular vesicle that transfers melanin from melanocytes unto keratinocytes of the epidermis
Define Merkel cell
receptor cell in the stratum basale of the epidermis that responds to the sense of touch
Define metastasis
spread of cancer cells from a source to other parts of the body
Define nail bed
layer of epidermis upon which the nail body forms
Define nail body
main keratinous plate that forms the nail,
Define nail cuticle
fold of epithelium that extends over the nail bed, also called eponychium
Define nail fold
fold of epithelium that extends over the sides of the nail body, holding it in place
Define nail root
part of the nail that is lodged deep in the epidermis from the which the nail grows
Define Pacinian corpuscle
receptor in the skin that responds to vibration
Define papillary layer
superficial layer o the dermis, made of loose, areolar connective tissue
Define reticular layer
deeper layer of the dermis; is has a reticulated appearance due to the presence of abundant collagen and elastin fibers
Define rickets
disease in children caused by vitamin D deficiency, which leads to the weakening of bones
Define scar
collagen-rich skin formed after the process off wound healing that is different from normal skin
Define sebaceous gland
type of oil gland found in the dermis all over the body and helps to lubricate and waterproof the skin and hair by secreting sebum
Define sebum
oily substance that is composed of a mixture of lipids that lubricates the skin and hair
Define second degree burn
partial thickness burns that injures the epidermis and a portion of the dermis
Define squamous cell carcinoma
type of skin cancer that originates from the stratum spinosum of the epidermis
Define stratum basale
deepest layer of the epidermis, made of epidermal stem cells
Define stratum corneum
most superficial layer of epidermis
Define stratum gra limingnulosum
layer of epidermis superficial to the stratum spinosum
Define stratum lucidum
layer of epidermis between the stratum granulosum and stratum corneum, found only in thick skin covering the palms, soles of the feet and digits
Define stratum spinosum
layer of the epidermis superficial to the stratum basale, characterized by the presence of desosomes
Define stretch mark
mark formed on the skin due to a sudden growth spurt and expansion of the dermis beyond its elastic limits
Define sudoriferous gland
sweat gland
Define telogen
resting phase of the hair growth cycle initited with catagen and terminated by the beginning of a new anagen phase of hair growth
Define third degree burn
burn that penetrates and destroys the full thickness of the skin (epidermis)
Define vitamin D
compound that aids absorption of calcium and phosphates int he intestine to improve bone health
Define vitiligo
skin condition in which melancytes in certain areas lose the ability to produce the melanin, possibly due to an autoimmune reaction that leads to loss of color in patches
