chapter 1: types of epithelium Flashcards
epithelium that is single cell thick
simple epithelium
single layer of flattened cells
simple squamous
epithelium that:
living filter
provide a barrier (thin)
simple squamous
single layer of cubed shaped cells; nucleus occupies much of the cell cytoplasms, typically looks square when sectioned for a slide
simple cuboidal
epithelium (2) that is used in:
- absorption
- secretion
- provides barrier
simple cuboidal
simple columnar
single layer of cells that have height, more cytoplasm than simple cuboidal, typically look rectangular under slide
simple columnar
ciliated pseudostratified columnar epithelium is AKA
respiratory epithelium
epithelium with 3 cell types of various heights so it can have the appearance of stratified epithelium
ciliated pseudostratified columnar epithelium
different cell types of ciliated pseudostratified columnar epithelium
goblet
ciliated columnar
basal
modified columnar cell that functions to produce mucus
goblet cells
columnar cells that contain CILIA; cilia are anchored in the apex of the cell by basal bodies; function to MOVE MUCUS over surface
ciliated columnar cells
short pyramidal shaped cell that does not reach the surface; function to be the STEM cell for this type of epithelium
basal cells (STEM CELLS)
types of surface specializations
microvilli
stereocilia
cilia
glycocalyx
finger-like projections at the apical surface on some epithelial cells; also called a brush border or striated border
microvilli
surface specialization cells that function to increase surface area to increase absorption
microvilli
extremely long microvilli; usually fewer present than in microvilli; not related to true cilia– NON-MOTILE; quite rigid
stereocilia
thin apical hair-like extensions of cytoskeleton that function to move something over a surface
cilia
cells with cilia have many ________ to make ATP, and BASAL bodies to block the free surface so there is NO ______ or ______
mitochondria
secretion
absorption
surface layer of glycoproteins and carbs that covers some epithelium (protection); produced by SOME epithelial cells
glycocalyx
functions of glycocalyx
protection
cell recognition
(possibly cell adhesion, hold enzymes)
epithelium that is 2+ layers thick
stratified epithelium
epithelium that is named for the shape of its superficial cells and has a PROTECTIVE function
stratified epithelium
epithelium that is multiple layers of cells that tend to flatten out from basal layer to superficial later; superficial layer of cells are flat and alive
stratified squamous
epithelium with functions:
protection from ABRASION/FRICTION
stratified squamous
problems/limitations of stratified squamous
no protection from drying
limited thickness so protection is limited
multiple layers of cells that also tend to flatten from basal layer to superficial layer of cells; superficial cell layer is covered by an added nonliving layer of keratin
keratinized stratified squamous
layers in epithelium of skin
stratum basale stratum spinosum stratum granulosum stratum lucidum stratum corneum
function of epithelium is protection in a DRY environment
keratinized stratified squamous
1-2 layers of keratinocytes which are MITOTIC and closest to dermis
stratum basale
multiple layers of “spiny shaped” keratinocytes that produce lipids and keratohyaline vacuoles. Keratinocytes have cytokeratin monofilaments that radiate outward from nuclear region; thickness of layer varies
stratum spinosum
uppermost 2-5 layers of flattened living keratinocytes that contain flattened, condensed keratohyaline granules ; EXOCYTOSIS of lipid-filled lamellar granules will occur from these cells
stratum granulosum
thin layer of recently dead or dying keratinocytes present only in THICK skin; layer is NOT easy to see; nucleus and organelles are NOT present
stratum lucidum
layer of dead cells, keratin and lipids; thickness of this layer varies but has 3 functions:
- prevents water loss
- provides barrier to microbes
- protects against abrasion
stratum corneum
________ contributes to strength to this STRATUM CORNEUM by increasing SA for attachment of epithelium to CT below
epidermal pegs (rete ridges) dermal papillae
epithelial cell types in keratinized stratified squamous epithelium
keratinocytes
melanocytes
langerhan cells
merkel cells
typical cell type found throughout keratinized stratified squamous epithelium
- can divide in stratum basale
- produce keratins/keratohyaline granules & lipids when in stratum granulosum
keratinocytes
epithelial cells (in keratinized stratified squamous epithelium) that protect against UV radiation
melanocytes
melanocytes are found in which layer:
stratum basale
how melanocytes work
keratinocytes phagocytize the cytoplasmic tip of melanocytes containing the melanosomes with melanin
skin color is greatly influenced by:
environmental influences
genetics
# blood vessels in dermis
cells that recognize and process external foreign antigens; antigen presenting cells
langerhan cells
langerhan cells found in layer:
stratum spinosum
cells that provide touch receptors
merkel cells (AKA tactile cells)
merkel cells found in:
stratum basale
______ # increase when exposed to UV light repeatedly
melanocytes
______ # decrease with repeated UV exposure
langerhan cells
two layers of cells; basal layer is typically flattened; superficial layer of cells is CUBOID in shaped- not common
stratified cuboial
epithelium that fxn:
increase protection
provide a barrier
stratified cuboidal
two layers of cells; basal layer is typically flattened; superficial layer of cells is COLUMNAR in shaped- very RARE
stratified columnar
epithelium that fxn:
- increase protection
- provide transition between epithelial types
- provide barrier
stratified columnar
multiple layers of cellsfunction:
- provide protection
- STRETCHbarrier
transitional (urinary)
specialization of transitional epithelium
thin, fenestrated basement membrane
large/round superficial cells
well-developed occludens
why specialization of transitional epithelium are important
need tight junctions because of fenestrated basement membrane
prevents waste/urine from seeping between epi cells
unusual superficial cell feature
some bi-nucleate superficial cells
cells obtain more oxygen because of (2)
fenestrated basement membranewhen stretched, diffusion distance is increased
