skin structure and function Flashcards
The skin provides a ________ that regulates water loss
physical barrier
Skin protects against
mechanical, chemical, and microbial insults
chronic skin condition associated with barrier dysfunction of filaggrin
atopic dermatitis
atopic dermatitis
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The skin helps maintain ___________ with the insulating properties of fat and hair
constant body tomperature
Temperature regulation: Accelerating heat loss with _________ and a dense superficial microbasculature
sweat production
dysfunction of temperature regulation
hyper or hypothermia
the dark pigment ______ in the _____ protects the cells against Ultraviolet radiation
melanin
epidermis
Dysfuntion of _________ causes the patient to be more susceptible to skin cancer
melanin
_____________ receptors allow constant monitoring of the environment
sensory
_______ in the skin are important for interaction with physical objects
mechanoreceptors
itching
pruritis
dysesthesia
abnormal sesnation
four phases of cutaneous wound repair process
- coagulation
- inflammation
- proliferative-migratory phase (tissue formation)
- remodeling
loss of ability to repair injury leads to
delayed wound healing
HIV associated lipoatrophy
loss of fat throught the face, atrophy of buccal fat pads gives the appearance of facial wasting
three layers of the skin
epidermis
dermis
subcutis
topmost layer of skin and its composition
epidermis consists primarily of keratinocytes
contents of dermis
fibroblasts, collagen, elastic fibers
deepest layer of skin
subcutis or hypodermis
subcutis cells
fat and larger blood vessels
layers of the epidermis from superficial to deep
stratum corneum
(stratum lucideum)
stratum granulosum
stratum spinosum
stratum basale
it takes _______ for basal cells to reach the stratum corneum
2 weeks
it takes _____ for epidermal cells to shed
2 weeks
which layer does epidermal cell division happen?
basal layer
keratinocytes start in basal layer and move
upward
most common form of skin cancer
basal cell carcinoma
basal cell carcinoma histology
pearly, erythematous papules or plaues with rolled borders and telangectasias in sun exposed areas
spinous layer
center of epidermous
has a spiny appearance due to desmosomal junctions which hold keratinocytes together
lipids produced by the keratinocytes in the_____ cell layer and secreted into the exgtracellular space between the keratinocytes forms a ______ that keeps ___ in the skin
granular
water barrier
water
stratum corneum
desquamating keratinocytes
thick outer layers of flattened keratinized non nucleated cells provide a barrier against trauma and infections
stratum corneum is similar to
brick and mortar
brick - flattened keratinocytes with keratin and fillagrin
mortar - lipid mixture, which surrounds the keratinocytes and provides the water barrier
_____ retains water within the keratinocytes and is found in what cell layer?
filaggrin
granular
bullous pemphigoid
autoimmune blistering disease with autoantibodies to antigents on hemidesmosomes that anchor basal layer to dermis
presents as tense bullae on an erythematous base
epidermis forms roof of blister and dermis forms base
Psoriasis
the rate of epidermal turnover is increased
scaling of startum corneum
in psoriasis, the accelarated rate of movement through the epidermis doesn’t allow adequate time for ______ which is recognized as _____
differentiation
scale
what condition?
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HIV lipoatrophy
layers of skin
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bullous pemphigoid
epidermis and bottom layer is dermis
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psoriasis
three types of cells in epidermis
keratinocytes
melanocytes
langerhans cells
majority of cells in epidermis
keratinocytes
keratinocytes are held together by
desmosomes
melanocytes
what they produce
where they are found
staggered along the basal layer about 1 in every 10 keratinocytes
produce and transfer a pigment called melanin in the basal layer
melanocytic nevi
moles, benign collections of melanocytes
melanoma
malignancy of melanocytes
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melanoma
langerhans cells
dendritic cells found in the mid-epidermis
Langerhans cells function in the ______ lumb of the immune response by …
afferent
providing for the recognition, uptake, processing, and presentation of antigens to sensitized T lymphocutes
langerhans cells are important in the induction of
delayed hypersensitivity reactions
common skin disease in which langerhans play a prominent role is
allergic contact dermatitis
what cells are these
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langerhans cells
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contact dermatitis from poison oak
layers of the dermis
papillary dermis
reticular dermis
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red = epidermis
blue= sebaceous gland
green = reticular dermis
yellow = hair follicle
how thick is the dermis?
thicker than epidermis
between 1-4 mm thick
contents of dermis
blood, lymphatic vessels, and nerves which supply the skin
sweat glands and hair follices
types of cells in the dermis
fibroblasts and mast cells
______ are responsible for synthesis and degradation of connective tissue proteins
fibroblasts
these cells are instrumental in wound helaing and scarring
fibroblasts
keloids
abnormal scars - result from uncontrolled synthesis and excessive deposition of colalgen at sites of prior dermal injury and wound repair
mast cells
specialized cells that are responsible for immediate- type hypersensitivity reactions in the skin
release histamine
major effector cell in urticaria
mast cell
urticaria
vascular reaction of the skin characterized by wheals surrounded by a red halo or flare
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keloids
The fat layer which separates the dermis from deeper underlying structures such as fascia and muscles
subcutis
subcutis
insulates the body, serves as an energy supply, cushions and protects the skin, and allows for mobility over underlying structures
erythema nodusum
panniculitis (inflamation of the subcutis)
deep seated erythematous nodules typically on the shins
may be idopathic or a reaction to infections, medications or autoimmune (crohns) disease
pilosebaceous unit
hair/oil gland unit
- hair follicle
- sebaceous (oil) glands
- apocrine sweat glands (axillary and anogenital)
- arrector pili muscle - goosebumps
acne vulgaris
disorder of the pilsebaceous unit
- plugging of hair follicle as a result of abnormal keratinizatino of the upper portion
p. acnes bacteria in the hair follcle lives on oil and breaks it down to free fatty acids which cause inflammation
eccrine glands
sweat glands that do not involve the hair follicle
open directly onto the skin so cooling evaporation can take place
molluscum contagiosum
a skin infection caused by HIV
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molluscum contagio\sum