L2: Epithelium Flashcards
where is epithelia tissue found
body surfaces
lines hollow organs, cavities and ducts
forms glands of the body
key functions of epithelial tissue
selective barrier
secretory
protective
types of cell junctions
tight
adherens
desmosomes
hemidesmosomes
gap
composition of the cytoskeleton
microfilaments and intermediate filaments
function of microfilaments
strength
alter cell shape
link cytoplasm to membrane
tie cells together
muscle contraction
proteins involved in tight junctions
claudins and occludins
tight junctions are common in the
stomach
intestines
bladder
how do tight junctions maintain cell polarity
preventing migration of proteins between apical and basal surfaces
proteins involved in adherens junctions
cadherins and catenins
plaque layer in adherens junctions links what to what
actin to cadherins
function of adherens junctions
prevent cell separation from tension forces like in contractions
proteins involved in desmosome junctions
cadherins and desmoplakin
desmosome junctions link what to what
link cell surface to keratin
desmosome junctions are common in
skin epithelium and cardiac cells
function of desmosome junctions
resist shearing forces and bind muscle cells
proteins involved in gap junctions
6 connexIns make 1 connexOn
what size molecules do gap junctions allow through
up to 1kDa
function of hemidesmosome
connect epithelia to basement membrane
link keratin to basement membrane
proteins involved in hemidesmosomes
integrin
laminin
keratin
junctional complex
tight + adherens junctions + desmosome
composition of basement membrane
basal and reticular lamina
describe basal lamina
secreted by epithelial cells
contains collagen, laminin, proteoglycans and glycoproteins
describe reticular lamina
produced by fibroblasts in CT
contain fibrous proteins like collagen, fibronectin
function of basment membrane
support overlying epithelia
migratory surface for epithelia cells during growth and wound healing
physical barrier
filtration of substances in kidney
in melanoma, the diameter is greater than ___
6mm
two types of epithelial tissue
covering and lining
glandular
function of covering epithelia
cover exposed surfaces and internal cavities
transitional epithelium is found in the
bladder
simple squamous epithelium found where there is
diffusion
filtration
secretion where slippery surface needed
specialised subtypes of simple squamous epithelium
mesothelium
endothelium
mesothelium lines
peritoneal, pleural and pericardial cavities
endothelium lines
inside of heart and blood and lymphatic vessels
simple cubodial epithelium is found where there is
secretion and absorption
subtypes of simple columnar epithelium
non-ciliated and ciliated
function of goblet cells
secrete mucous
non-ciliated simple columnar epithelium is found where there is
secretion, absorption and lubrication
ciliated simple columnar epithelium is found in
bronchioles
fallopian tubes
brain ventricles
central canal of spinal cord
sinuses
function of ciliated simple columnar epithelium
synchronous movements assist in motility of mucus and foreign objects and oocytes
specialised subtypes of stratified squamous epithelium
keratinised and non-keratanised
all forms of stratified squamous epithelium protect against
microbes
keratinised stratified squamous epithelium is found
where mechanical stress and dehydration are major issues ie. dry trauma areas
non-keratanised stratified squamous epithelium is found in
wet trauma areas
function of non-keratinised stratified squamous epithelium
protection from abrasion
pseudo-stratified columnar epithelium subtypes
ciliated and non-ciliated
stratified cubodial epithelium is found in
ducts of adult sweat glands oesophageal glands
male urethra
stratified columnar epithelium is found in
part of urethra
oesophageal glands
anal mucosal membrane
conjunctiva of eye
secretion pathway of endocrine glands
directly into blood via traversing interstitial fluid
secretion pathway of exocrine glands
into ducts that empty on surface of covering or lining epithelium
single cell exocrine glands
eg. mucous cells, goblet cells
simple gland
duct doesn’t divide on way to gland cells
branched gland
several secretory areas share one duct
where are simple tubular glands
intestinal glands
where are simple coiled tubular glands found
merocrine sweat glands
where are simple branched tubular glands found
gastric glands
mucous glands of oesophagus, tongue and duodenum
simple alveolar glands are
a stage in the embryonic development of simple branched glands
where are simple branched alveolar glands found
sebaceous glands
what makes a gland compound
duct divides one or more times on way to gland cells
where are compound tubular glands found
mucous glands in mouth
bulbo-urethral glands
seminiferous tubules of testes
where are compound alveolar glands found
mammary glands
where are compound tubuloalveolar glands found
salivary glands
glands of resp. passage
pancreas