Chapter 5 Epithelium Flashcards
what are the characteristics of epithelial cells
organized, cohesive, shape dictates function, avascular and contain cytokeratins, polarized
what are cytokeratins
unique to epithelium group of proteins that are expressed as intermediate filaments
basal lamina
lamina dense and lamina lucida
reticular lamina
derived from connective tissue, has connective tissue reticular fiers
apical surface
Adjacent to the lumen
basal surfac
adjacent to the basal lamina
what are the functions of the epithlium
protection, absorption, secretion, transport, contractility and sensation
What are the four types of junctions
tight junctions, adhering junctions, gap junctions and macula adherens or desomosomes
characteristics of tight junctions
belt around the cell, fusion of adjacent cell membranes, and prevents movement of materials between adjacent cells (ex: blood brain barrier)
characteristics of zonula adherens
actin filaments insert into plaques, connect to neighboring cells via cell adhesion molecules (CAMs), actin filaments form an intterconnected network all away around the cell
desmosome or (macular adherens)
attachmen plaque, intermediate cytokeratin filaments, cadherin family, function as tight adjesion between cells
Hemidesmosomes
attachment plaque, intermediate cytokeratin filaments, use integrins instad of cadherins and unction in tight adhesion to the BASAL LAMINA, connects to basement membrane
gap junctions
connexins, generate a centrla porem function in communication
where is simple squamous epithelium found
bowmans capsule of kidney, alveoli
where is simple cuboidal epithelium found
kidney tubules
where is simple columnar epithelium found ?
intestines, has a brush border
microvilli
apical finger like extens to increase surface area on actin, glycocalyz and brush border in the intestine
where is pseudostratified columnar epithelium found ?
digestive tract
cilia
have a 9+2 microtubule arrangement and are motile (9 doublets around 2 tubules)
if cilia are immobile what are they called
sterocillia
stratified squamous
the more layers you have the more protection, example is skin(keratinized) non keratinized (oral cavity, pharnyz, anus or vaginal opening)
where is stratified cuboidal epithleium found
in large ducts
where is stratified columnar epitheliu found
male reproductive tracts
transitiional epithelium
found in the bladder and proximal portion of the utereters
serous glands
secrete watery substance that is rich in enzymes
package of enzymes
zymogens
cells form spherical structures
alveolus (acinus)
mucous glands
secretion is viscus or mucus and mucous gland cells form tubules
serous demilune
serous cells from a cap over the mucus tubule (example is salivary glands)
merocrine
no lossof cytoplasm, most common mode of exocrine gland (salivary gland)
holocrine
entire cell is lost (sebaceous gland-oil gland)
apocrine
apical cytoplasm is lost (mammary gland during lactation)
classification of exocrine glands can be
duct system (simple or compound), secretory unit (tubular, alveolar, tubuloalbeolar) and unicellular and multicellular
myoepithelial
help push secretion
What are the hallmarks of steroid secreting cells >
lipid droplets, lots and lots of smooth ER, and small amount of RER
epithelial sit on top of a basement membrane that consists of 2 main layers __________ and ______________
basal lamina and reticular lamina
basal lamina consists of what
lamina dense and lamina lucida
