Integumentary Flashcards
skin
- layers
- general composition of each layer
epidermis
-epithelial layer (ectoderm)
dermis
-connective tissue (mesoderm)
dermis
-interdigitation properties
dermal papillae
-projections of dermis into epidermal base
epidermal ridges
-adjoining epidermal projections that correspond to dermis surface
interdigitations
- purpose
- take what type of configurations in thin vs. thick skin
purpose -provide structural and morphological integrity between epidermis and dermis (in addition to cellular connections) configuration in thin skin -peg and socket thick skin -ridges and grooves
hypodermis
- location
- type of tissue
- contains
- how does it connect to skin?
- underlying tissue covered by…
location
-deep to dermis
tissue type
-subcutaneous loose connective tissue
contains adipocytes (fat cells)
not part of skin, but forms loose adhesion of skin to underlying tissue
underlying tissue covered by a fascia plane, which has a variable appearance
skin functions (4)
receptor organ
protection against impact and friction
protection against UV - pigment melanin
thermoregulation, body metabolism and excretion via glands, blood vessels, and adipose
epidermis
- type of tissues
- contains
type
-stratified squamous keratinized epithelium (named for most superficial strata of epidermis)
contains
-keratinocytes - keratinizing epidermal cells
-melanocytes
-langerhans cells - immune system
-merkel cells - sensory receptors?
skin thickness
- epidermis
- dermis + epidermis
epidermis -75-150 um (micrometers) vs. 400-600 um --no explanation of comparison in notes (different areas of the body?) total -up to 4 mm
types of skin
-characteristics
thick (glabrous) -smooth, non-hairy -some books use stratum lucidum as a marker for this type of skin thin -hairy
keratin producing cells (keratinocytes) in epidermis
-names of the layers (5)
stratum basale stratum spinosum stratum granulosum stratum lucidum stratum corneum
stratum basale
- superficial or deep?
- it is basophilic - explain
- single cell layer rests on…
- purpose of desmosomes and hemidesmosomes
- produce filaments called…
- highly mitotic - why?
deepest layer
basophilic
-abundant in rough ER (endoplasmic reticulum)
-these produce protein
single cell layer rests on basal lamina
desmosomes and hemidesmosomes attach stratum basale to underlying layer
produce filaments called cytokeratins
high mitotic
-partly responsible for constant renewal of overlying layers
stratum spinosum -how many layers -cell shapes -mitotic or not -tonofibrils where is this layer thicker?
more than 1 layer
shapes
-variety: cuboidal, polygonal, “slightly” squamous
mitotic
tonofibrils
-tonofilament bundles that attach to the desmosomes interconnecting each cell
-give the spinous appearance in histological preparations
thicker in areas of greater abrasion
stratum granulosum
- how many layers
- what shape are the cells?
- stains dark due to…
- purpose
- -what structures are responsible for this process?
3-5 layers polygonal cells stains dark due to... -keratohyalin granules purpose -acts as extracellular cement -purpose achieved due to lamellar granules --lipid-rich product secreted by these cells to "seal" the skin
stratum lucidum
- more apparent in…
- appearance
- type of cell
- lacks what function…
- what structures are missing?
- densely packed with…
- what holds the cells together?
more apparent in thick skin appearance -extremely flattened type of cell -eosoniphilic lacks protein synthesis organelles and nuclei are gone densely packed with cytokeratin filaments embedded in matrix desmosomes present to hold cells together
stratum corneum
- appearance
- is there a nucleus?
- thickness
- filled with…
- -this is embedded in
flattened cells no nuclei 15-20 layers thick filled with protein keratin keratin is embedded in matrix from keratohyalin granules (from stratum granulosum)
other cells found in epidermal layers
- names
- primarily found in which layers?
melanocytes
langerhans cells
merkel’s cells
primarily found in stratum basale and spinosum (2 deepest layers)
melanocytes
- origin
- location
- function
neural crest in origin
found in and beneath stratum basale
produce melanin
melanin
- purpose
- how do they accomplish this purpose?
- how does it get moved through the skin?
purpose
-encircle the nucleus of the keratinocytes to protect their genetic material from UV radiation
movement
-melanin is packaged into vesicles (through a series of changes that darken and condense) and then extruded and picked up by cells of the malpighian layer
sun tan
-what does it do to melanin
increases the “darkening” of melanin
speeds up release into the malpighian layer
what is the malpighian layer?
Wikipedia - both the stratum basale and stratum spinosum
langerhans cells
- what are they?
- purpose
bone marrow derived macrophages (mesoderm)
purpose
-bind antigens (function with immume system)
Merkel’s cells
- location
- purpose
within thick skin
purpose
-may be sensory due to association with free nerve endings
where are the majority of sensory nerve endings in the skin?
dermal layer
dermis
- type of tissue
- layers
- -characteristics of each layer
tissue type -connective -dense irregular papillary layer -dermal pegs -lamina reticularis: reticular fibers that contribute to basement membrane reticular layer -dermatan sulfate elastic fiber newtork
dermis
- characteristics
- location of blood supply
encapsulated nerve endings
epithelial invaginations
rich blood supply
-deep to epidermis-dermis interdigitation
