Day 2 epithelial tissue Flashcards
many simillar cells working together form what?
A tissue
What are the functions of epithelial tissue? (4)
physical protection
controls permeability
provides sensation
secretions
typically epithelial tissue is found near what type of tissue?
connective tissue
What are three characteristics of epithelial tissue?
cellularity- composed almost entirely of cells
Polarity- exposed [apical] and basal surface
Attachments- Basal layer to basement membrane adjacent cells
this organelle is found in high concentration in muscle cells and lower levels in bone cells
mitochondria
what is an example of an epithelial cell that shows polarity? think location and function
epithelium that lines most of the respiratory tract. The small bristly area are micro villi found on the exposed surface of mucus producing cells
epithelial tissue is typically found in close proximity to connective tissue why is this?
because epithelial tissue is avascular
what are the three shapes of epithelia?
squamous
cubodial
columnar
what is the epithelial classification based on number of layers?
simple
stratified
pseudostratified
transitional epithelium
Simple epithelia can be what?
squamous
cuboidal
columnar
stratified epithelia can be what?
squamous
Maybe cuboidal sometimes
where do you find simple squamous epithelium?
pleural pericarial and peritoneal body cavities; andothelia lining heart and blood vessels; alveoli of lungs
what is the function of simple squamous epithelium?
reducess friction
controls vessel permiability
performs absorption and secretion
where is stratified squamous epithelium found?
surface of skin
lining of oral cavity
throat
esophagus
rectum
anus
vagina
what is the function of stratified squamous epithelium?
provides physical protection against abrasions, pathogens and chemical attacks
where is simple cuboidal epithelium found?
glands ducts and kidney tubules
what are the functions of simple cuboidal epithelium?
limited protection
secretion
absorption
what is the location of stratified cuboidal epithelium?
lining of some ducts (rare)
what is the function of stratified cuboidal epithelium?
protection secretion and absorption
What is the location of simple columnar epithelium?
linings of stomach and intestines
what is the function of simple columnar epithelium?
protection secretion and absorption
what is the location of stratified columnar epithelium?
mammary glands and salivary glands
what is the function of stratified columnar epithelium?
protection
what is the location of psudostratified ciliated columnar epithelium?
lining of nasal cavity nasal cavity trachea bronchi portions of male reproductive tract
what is the function of psudostratified ciliated columnar epithelium?
protection and secretion
What is unusual about psudostratified columnar epithelium?
looks like stratified but it is one layer thick
What is the location of transitional epithelium?
urinary bladder; renal pelvis; ureters
what is the function of transitional epithelium?
permits expansion and recoil after streching
what are tight junctions also called?
occluding juctions
what is the zonula adherens also called?
adhesion belt
what are the button desmosomes also called?
macula adherens or desmosomes
what are communication junctions also called?
gap junction
what do tight junction do?
prevents movement of substances to underlying tissues or water-soluble materials in intercellular space
ex epithelium of digestive wall
zona adherens what is an example? what are the characterisitcs?
cams and proteoglycans form junctions with cytoskeleton filaments
often at terminal web
ex. superficial layer of skin
where are Hemidesmosomes found?
they have a strong attachment to basal lamina
found where there is a lot of sheering
ex. esophagus
gap junctions are used for what?
communicating junctions between cells; chemical and electrical coupling
epithilial cells with cilia, neurons or cardiac muscle
ex. produce synchronous activation of heart muscles
