Integument Flashcards
Basic layers of skin
epidermis, dermis, hypodermis
Basic functions of integument
Protection Thermoregulation Sensory organ Metabolic Excretion of excess H20, salt, and nitrogenous metabolic wastes through sweating
Thick skin
Palms of hands and soles of feet
No hair follicles
Thin skin
skin other than palms and soles
thinner epidermis, hair follicles —with some exception
Keratinocytes produce
keratin
Epidermis
stratified squamous epithelial cells
Cells accumulate more keratin as they migrate from
basal layer
epidermis requires ______ days for cells to mature and desquamate
25-50
Protection portion of integument functions
mechanical thermal chemical UV radiation dehydration
Thermoregulation portion of integument functions
vascular network in dermis, sweat glands
Sensory portion of integument
touch, temperature, pain
metabolic portion of integument
vitamin D3 synthesis in epidermis. Energy storage (fat-triglycerides-hypodermis)
Name the epidermal layers
Stratum basale (germinativum) Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum
Stratum basale (germinativum) is compose of a
single layer of columnar to cuboidal cells
Stratum basale contain numerous
intermediate filaments (tonofilaments)
In stratum basale, hemidesmosomes bind cells to
basal lamina
In stratum basale, desmosomes on the
lateral and upper surface
Within the stratum spinosum layer of epidermis, the cells are
cuboidal, polygonal, to slightly flattened
Cell processes of stratum spinosum is filled with
intermediate filaments and terminate with desmosomes
(in stratum spinosum), cells accumulate fibrillar protein (cytokeratin)-aggregate to form
tonofibrils
________ figures are also present in the stratum spinosum layer
“mitotic” figures
This layer is composed of 3-5 layers of flattened polygonal cells
stratum granulosum
cytoplasm of stratum granulosum has what type of granules
basophilic keratohyaline granules
keratinosomes are
lamellar granules formed by lipid bilayers which fuse with cell membrane and discharge contents into intracellular spaces of the S. granulosum
(Stratum granulosum) the glycolipid acylglucoceramide serves as a
penetration barrier to foreign material and to maintain hydration of the body
Stratum lucidum can only be found in
thick skin, but not evident in all thick skin
Stratum lucidum is a thin layer of
eosinophilic, newly keratinized cells
Cells of stratum lucidum contain no organelles but do contain_______
eleidin (transformation product of keratohyalin)
Stratum corneum
15-20 layers of flattened non nucleated cells filled with keratin
Within stratum corneum, dead flattened cells are called
squames
How does skin heal?
If epidermis is injured, surrounding basal cells migrate and divide to cover the wound.
This vitamin is necessary for proper skin healing because it is needed for keratinocyte differentiation
Retinol (Vitamin A)
First degree burns extend to which layer of epidermis
1st degree burns extends down to S. lucidum
Second degree burns extent dow to
S. basale
3rd degree burns go down into
dermis
protein that aggregates keratin filaments
Filaggrin
If epidermis is injured….
surrounding basal cells migrate and divide to cover the wound
Kerationcyte differentiation
Different keratins are expressed as keratinocytes differentiate (from basal layer to s.spinosum to s.granulosum).
In s. granulosum, _________ are secreted to form multilayered lipid layer on the outside of the cell membrane
glycolipids
In the s. corneum, a protein complex of_______-_____ ______-____-_____ complex and keratin-filagrin aggregates link to the cytoplasmic side of the membrane
involucrin-small proline-rich-loricrin complex
(melanocytes) pigment producing cells of S. basal are derived from
neural crest
melanocytes
pigment producing cells of S. basal derived from neural crest
Lack of cortisol from the adrenal cortex causes
overproduction of ACTH—increases skin pigmentation (Addison’s disease)
In albinism, melanocytes do not make
melanin