Epithelia Flashcards
Define epithelium
Thin, continuous protective layer of cells that covers both the inside and outside of the body including blood vessels
What are the functions of epithelia?
Protection, secretion, absorption, excretion, filtration, diffusion and sensory reception
Which embryological germ layer are epithelial tissues derived from?
All 3- endoderm, ectoderm and mesoderm
Which epithelial tissues are formed from the ectoderm?
The skin
Which epithelial tissues are formed from the endoderm?
Gastrointestinal tract, respiratory tract, genitourinary tract, external acoustic meatus
(Interior spaces opening to exterior)
Which epithelial tissues are formed from the mesoderm?
Pericardial sac, pleural sacs, peritoneum, blood vessels, lymphatic vessels
(Interior spaces which do not open to exterior)
What is the function of simple squamous epithelia?
Diffusion and filtration (due to thinness)
What is the function of simple cuboidal epithelium?
Absorption, secretion and protection
Give an example of simple squamous epithelium
Bowman’s capsule
Give an example of simple cuboidal epithelia
Lining of the collecting ducts of the kidney
What is the function of simple columnar epithelium?
Absorption of nutrients, movement of lumen contents.
Give an example of simple columnar epithelium
Lining of the crypts of Lieberkuhn
What is the function of stratified squamous epithelia?
Protection from abrasion
Give an example of stratified squamous epithelium
Lining of the wall of the oesophagus
What is the function of transitional epithelium?
Protection and distendibility
Give an example of transitional epithelium
Lining of the urinary tract (renal calyces, ureters, bladder, proximal urethra)
What is the function of microvilli?
Absorption
What is the function of stratified squamous keratinised epithelium?
Protection against abrasion, prevention of water loss
What is the name for the layer of outermost dead cells of stratified squamous keratinised epithelium?
The stratum corneum
Give an example of pseudostratified epithelium
Lining of conducting airways eg. Trachea
What is the function of pseudostratified epithelia?
Secretion and absorption
What is the function of cilia?
Motile, beat in order to move substances through the lumen
What is the function of goblet cells?
Secretion of mucins (forms mucus when in contact with water)
What is a serous membrane?
A membrane which surrounds the invaginated organ eg. Heart, lung, gut. Has inner and outer membrane.
Hand in balloon analogy
What is the difference between serous and mucosal membranes?
Mucosal membranes line internal structures which open to the exterior eg. GI, respiratory, urinary tract
Serous membranes line closed body cavities eg. Peritoneum, pleural sacs, pericardial sac
What is the function of club cells?
Protect the bronchiolar epithelium via the secretion of proteins including uteroglobin
Detoxification of harmful substances inhaled into the lungs with cytochrome P450 enzymes on SER
Act as a stem cell, differentiating into ciliated cells to regenerate the bronchiolar epithelium
