Chapter 6: Integumentary System Flashcards
oily secretion of sebaceous glands; keeps hair and skin from becoming dry brittle and cracked
sebum
entire cell breaks up to form secretion
holocrine secretion
sheep sebum
lanolin
what secretion does sebaceous glands use?
holocrine secretion
ceruminous glands are modified apocrine glands in
external ear canal
sebum and dead epithelial cells form
earwax (cerumen)
milk producing glands that develop only during pregnancy and lactation
mammary glands
two rows of mammary glands in most mammals
mammary ridges; milk lines
multiple nipples
polythelia
what are the 3 kinds of skin cancer?
basal cell carcinoma, squamous cell carcinoma, and malignant melanoma
least common type of skin cancer; least dangerous because it seldom metastasizes; forms from cells in stratum basal; lesion is small shiny bump with central depression and beaded edges; cured with surgical removal
basal cell carcinoma
skin cancer; arises from keratinocytes of stratum spinosum; surgical removal
squamous cell carcinoma
most dangerous skin cancer; most likely to spread; least common; arises from melanocytes
malignant melanoma
ABCD rule for malignant melanoma
A: asymmetry: uneven sides; B: border irregularity; C: color: several colors; D: diameter- larger than pencil eraser
deaths from burns largely result from
fluid loss (immediate threat); infection, eschar
burned, dead tissue
eschar
removal of eschar
debridement
how are burns classified?
according to depth of damage
burn that only involves epidermis
first degree burn
partial thickness burn; involves part of dermis
second degree burn
full thickness burn; involves epidermis, all of dermis, and some deeper tissues; requires skin grafts and fluid replacement, infection control and supplemental nutrition
third degree burn
skin taken from another location on same persons body
autograft
graft taking epidermis and part of the dermis from an undamaged area such as the thigh or buttocks and grafting it into the burned area
split skin graft
skin from identical twin
isograft
temporary skin graft from unrelated person
homograft(allograft)
temporary skin graft from different species
heterograft (xenograft)
what is the integumentary system?
skin and accessory organs (hair nails sweat and sebaceous oil glands
scientific study and medical treatment of the integumentary system
dermatology
what is the body’s largest and heaviest organ?
skin
how many distinct regions does the skin have?
2
what are the two distinct regions of the skin?
epidermis and dermis
is the hypodermis part of the skin?
no but shares some functions
what is the hypodermis?
subcutaneous layer deep to skin; mostly adipose tissue that absorbs shock and insulates; anchors skin to underlying structures; mostly muscles
what kind of skin covers front of hands, bottoms of feet; has sweat glands, but no hair follicles or sebaceous oil glands; epidermis 0.5 mm thick?
thick skin
what kind of skin covers the rest of the body; possesses hair follicles, sebaceous glands, and sweat glands; epidermis about 0.1 mm thick?
thin skin
what are the functions of skin?
protection, body temperature regulation, cutaneous sensations, metabolic functions, blood reservoir, excretion of wastes
how many barriers does the skin have?
3: chemical, physical, biological
low pH of skin retards bacterial multiplication
acid mantle
skin secretes many chemicals such as sweat; which contains antimicrobial proteins, sebum and defensins which kill bacteria, cells also secrete antimicrobial defensin
chemical barrier
flat, dead keratinized cells of stratum corneum, surrounded by glycolipids, block most water and water soluble substances, some chemicals have limited penetration of skin
physical barrier
epidermis contains phagocytic dendritic cells; dermis contains macrophages; dna can absorb harmful uv radiation, converting it to harmless heat
biological barriers
unnoticeable sweat abt 500 mL
insensible perspiration
when body temp rises; dilation of dermal vessels: noticeable sweat abt 12 L a day
sensible perspiration
respond to stimuli outside body, such as temperature, touch, and pain; part of nervous system
cutaneous sensory receptors
what can disarm some carcinogens?
chemicals from keratinocytes
epidermis consists mostly of what kind of cell?
stratified squamous epithelium
what kind of cells are found in epidermis?
keratinocytes, melanocytes, dendritic cells, tactile cells
cells that produce fibrous keratin, protein that give skin its protective properties, most common cells of epidermis, tightly connected by desmosomes, millions slough off every day
keratinocytes
cells that produce pigment melanin
melanocytes
cells that are key activators of immune system system
dendritic cells
cells that are sensory receptors that sense touch
tactile cells
how many strata does thin skin have?
4
how many strata does thick skin have?
5
layer of skin: single layer of stem cells and keratinocytes, stem cells divide and give rise to keratinocytes that migrate towards skin surface to replace lost cells; also contains a few melanocytes and tactile cells (deepest epidermal layer)
stratum basale
layer of skin: several layers of keratinocytes joined together by desmosomes and tight junctions; named for appearance of cells after histological preparation (spiny); contains some dendritic cells
stratum spinosum
layer of skin: three to five layers of flat keratinocytes; cells contain dark staining keratohyalin granules, water resistant glycolipids that slow water loss; cells above this layer die; too far from dermal capillaries to survive
stratum granulosum
layer of skin: thin pale layer only found in thick; keratinocytes packed with protein eleidin
stratum lucidum
layer of skin: several layers (up to 30) of dead scaly, keratinized cells, resists abrasion, penetration, water loss
stratum corneum (surface layer)
thick accumulations of dead keratinocytes on hands or feet
calluses or corns
water retention is fostered by tight junctions between skin cells and the waterproofing glycolipids of the stratum granulosum; helps prevent dehydration, does not prevent the absorption of water by the stratum corneum when we soak in a bath
epidermal water barrier
how many layers of the dermis are there?
2
what are the 2 layers of the dermis?
papillary and reticular
superficial region of dermis that sense fingerlike projections up into epidermis
dermal papillae
ridges are called_____ and enhance gripping ability; contribute to sense of touch; sweat pores in ridges leave unique fingerprint pattern
friction ridges
lines in the reticular layer that are caused by many collagen fibers running paralel to skin surface
cleavage (tension) lines
dermal folds in reticular layer near joints (dermis is more tightly secured to deeper structures)
flexure lines
acute short term traumas to skin; fluid filled pockets that separate epidermal and dermal layers
blisters
extreme strecthing of skin
stretch marks
most significant factor in skin color
melanin
brownish black form of melanin
eumelanin
reddish yellow (sulfur containing) form of melanin
pheomelanin
pigment in red blood cells; adds reddish to pinkish hue to skin
hemoglobin
yellow to orange pigment; concentrates in stratum corneum and subcutaneous fat
carotene
blueness due to oxygen deficiency
cyanosis
redness due to increased blood flow to skin
erythema
paleness due to decreased blood flow to skin
pallor
milky white skin and blue-gray eyes due to genetic lack of melanin synthesizing enzyme
albinism
yellowing due to bilirubin in blood (can be comprised liver function)
jaundice
bruising
hematoma
patches of discolored skin caused by benign tumors of dermal capillaries
hemangiomas (birthmarks)
another name for hair is
pilus
slender filament of keratinized cells growing from a tube in the skin
hair
tube in the skin in which hair grows out of
hair follicule
fine, downy unpigmented hair that appears on the fetus in the last 3 months of developmemt
lanugo
fine, pale hair that replaces lanugo by the time of birth
vellus
longer coarser and more heavily pigmented hair
terminal
a swelling at the base where the hair originates
bulb
the remainder of the hair in the follicle
root
the portion of hair above the skin surface
shaft
bud of vascular connective tissue encased by bulb
dermal papilla
region of mitotically active cells immediately above papilla
hair matrix
structure of hair: central core
medulla
structure of hair: surrounds medulla
cortex
structure of hair: outermost layer
cuticle
extension of the epidermis lying adjacent to hair root
epithelial root sheath
derived from dermis but a bit denser
connective tissue root sheath
sensory nerve fibers entwining follicules
hair receptors
smooth muscle attaching the follicle to the dermis
arrector pili muscle
thinning of hair
alopecia
excessive undesirable hairiness in area that are not usually hairy
hirsutism
hard part of the nail
nail plate
overhangs the fingertip
free edge
visible attached part of nail
nail body
extends proximally under overlying skin
nail root
surrounding skin rising above nail
nail fold
separates nail fold from nail plate
nail groove
skin underlying the nail plate
nail bed
growth zone
nail matrix
opaque white crescent due to thickness of matrix
lunule
narrow zone of dead skin overhanging proximal end of nail
eponychium (cuticle)
