Module 5 Flashcards
what are the 3 layers of the skin
epidermis
dermis
hypodermis/subcutaneous layer
epidermis
the superficial portion of the skin
avascular
4-5 layers of stratified squamous epithelium
dermis
the deeper layer
primarily composed of CT
hypodermis/subcutaneous
lies deep within the dermis
consists of areolar and adipose tissue
an area of fat storage, blood vessel passage, and pressure nerve endings
what are the 5 layers of the epidermis
stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum
stratum basale
what cell type is found in stratum spinosum, granulosum, lucidum, and corneum?
keratinocytes
keratin
an intracellular fibrous protein that gives hair, nails, and skin their hardness and water-resistant properties
what are the 4 cell types in the epidermis
keratinocytes
melanocytes
langherans cells
merkel cells
keratinocytes
produce keratin which helps protect the skin and underlying tissue from heat, microbes, and chemicals.
what are lamellar granules?
produced by keratin
release a waterproof sealant
melanocytes
produce melanin
langherans cells
participate in immune responses
merkel cells
touch a sensory structure called a tactile (merkel) disk, and function in the sensation of touch
what are the 2 layers of the dermis
papillary
reticular
papillary layer
areolar CT
contains fine elastic fibers, dermal papillae, corpuscles of touch (Meissners corpuscles), and free nerve endings for sensations of heat, cold, pain, tickle, and itch
superficial layer
reticular layer
dense irregular CT
contains bundles of collagen fibers and some elastic fibers
well vascularized
has a rich sensory and sympathetic nerve supply
what are the 3 pigments responsible for skin and hair colour
melanin
carotene
hemoglobin
what are the 2 forms of melanin
eumelanin
pheomelanin
eumelanin
black and brown
pheomelanin
red
the amount of melanin present in our skin is
dependent on
a balance between available sunlight and folic acid destruction, and protection from UV radiation and vitamin
D production.
What structures constitute the integumentary system
Skin
Hair
Nails
Glands
Receptors
functions of the skin
Maintain body temperature
Protection
Sensory perception
Excretion
Synthesis of vitamin D
Immunity
Broad reservoir
3 parts of hair
shaft above the skin
root that penetrates the dermis and SC layer
hair follicle consisting of two epidermal layers surrounding the root
what is hair composed of
outer cuticle
inner medulla
innermost cortex
what is hair follicle made of
hair bulb
hair papilla
hair matrix
hair function
protection
thermal insulation
sensing light touch
3 glands associated with the skin
sebaceous (oil) glands
sudoriferous (sweat) glands
ceruminous glands (earwax)
sebaceous glands location
usually connected to hair follicles
absent in the palms and soles
sebum
moistens hairs
waterproofs and softens skin
inhibits bacterial growth
2 types of sudoriferous glands
apocrine sweat glands
eccrine sweat glands
apocrine sweat glands
limited to the skin of the axilla pubis and the areolae
ducts open to hair follicles
eccrine sweat glands
help to regulate body temperature through evaporation
eliminate wastes such as urea
cerumen
earwax
stratum basale/stratum germinativum
single layer
stem cells capable of cell division
attached epidermis to basal lamina
its function is to provide cells for the epidermis
basal cells
cuboidal-shaped stem cells
precursor to keratinocytes
stratum spinosum
provides strength and flexibility to the skin
spiny in appearance
8-10 layers of keratinocytes
has a layer of langherans cells (fx as macrophages)
keratinocytes in this layer release water-repelling glycolipids
stratum granulosum
where a water repellent sealant forms between cells
3-5 layers
cells are flatter, thicker membranes
generates large amounts of keratin and keratohyalin
stratum lucidum
present only in fingers, palms, and soles of feet
keratinocytes are dead and flattened
cells are densely packed with eleiden
eleiden
a clear protein rich in lipids
derived from keratohyalin
stratum lucidum
stratum corneum
most superficial layer
15-30 layers
dead cells
constant exposure to friction causes this layer to thicken and form a callus
fx of stratum corneum
prevents penetration of microbes and the dehydration of underlying tissues
provides mechanical protection against abrasion
how long does it take for the stratum corneum to be replaced completely?
4 weeks
dermal papillae
projections of the papillary layer of the dermis into the stratum basal of the epidermis
What is the function of the arrector pili muscles
Arrector pili muscles pull the hairs into a vertical position. The contraction of the muscles occurs under the stresses of fright, cold, or emotion.
Accessory structures of the skin include
hair
glands
nails
Vitamin D production by the skin depends on
Exposure to ultraviolet radiation
nerves and blood vessels are found mainly in the:
dermis
