Epithelium Flashcards
What’s the characteristic surface difference between epithelium and epithelioid tissues?
Epithelial tissue typically has a free surface, whereas epithelioid tissues resemble epithelium, but lack a free surface.
True or False: Epithelial tissue is the most cellular tissue in the body?
True
What epithelia classification does mesothelium fall under?
Simple Squamous Epithelium
What molecular complexes tightly bind epithelium together?
Tight Junctions
Name at least 1 epithelial tissue that is derived from ectoderm.
The skin epidermis and glands.
The lining of the gastrointestinal tract (including glands) is derived from what, embryologically?
Endoderm
Name at least two epithelial tissue examples that is derived from mesoderm.
The lining of the blood vessels, mesothelium, and the Bowman’s capsule.
What is the most abundant collagen found in the basal lamina?
Type IV collagen.
What type of proteins are found in the basal lamina that makes it PAS positive?
Glycoproteins
Do lymph vessels and hepatic sinusoids have a basal lamina?
NO, they do not have a basal lamina.
What two components make up a basement membrane?
Basal Lamina and Reticular Lamina
What is the order of the reticular lamina, epithelium, basal lamina, and the connective tissue starting at the apical surface of the epithelial tissue?
Epithelium -> basal lamina -> reticular lamina -> connective tissue
What 3 components make up the reticular lamina?
argyrophilic fibers, reticular fibers, and glycoproteins.
Name two of the three major functions of the basement membrane.
1) Selective Filtration Barrier
2) Scaffold for embryogenesis and regeneration
3) Stabilization of tissue shapes
Even through epithelial tissue does not have vessels, can it be innervated?
Yes, epithelial tissues may be innervated.
Which layer of cells do you use to give the epithelial tissue its classification?
Superficial Layer
Give two areas in the body where lightly keratinized stratified squamous epithelium could be found?
Esophagus and Vagina
Is transitional epithelium a simple or stratified epithelium? Also, what about pseudostratified epithelium?
Simple, both transitional and pseudostratified epithelium are simple classification, NOT stratified.
What are the 3 apical surface modifications that can be found on epithelial tissue?
Cilia, Stereocilia, and Microvilli
What are the domains and features of a Polarized Cell?
- Apical Domain (with differentiations of cilia, microvilli, or stereocilia) and that domain must face a lumen or external environment
- Basolateral Domain
- Tight Junctions (intercelleular junctions)
- Basement Membrane
Name 2 tubular structure lumina that simple squamous epithelium covers?
Ducts and Vessels (also other tubular structures too)
Give some examples of where simple squamous epithelium is found?
- Walls of alveoli
- Bowman’s capsules
- Inner surfaces of membranous labyrinth and tympanic membrane
Where is simple cuboidal epithelium found in the kidney? Also, what apical surface modifications can be found on it in the kidney? Does it always have this modification?
In the kidney tubules with a brush boarder (microvilli). No, does not always have a brush boarder.
Give example of where simple cuboidal epithelium can be found in the body.
- surface of ovary
- pigmented epithelium of retina
- glands and ducts
- terminal bronchioles
- choroid plexus
- anterior capsule of lens of eye
Where can simple ciliated columnar epithelium be found in the body?
- upper respiratory tract
- uterine tubes
- uterus
- paranasal sinuses
- central canal of the spinal cord
Where is simple non-ciliated columnar epithelium found in the body?
- digestive tract beginning with the cardia of the stomach
- gall bladder
- in parts of the excretory ducts of glands
What apical domain modification is sometimes found on simple columnar epithelium of intestinal cells?
Striated Border (microvilli)
What kind of epithelium has a striated border and where is it located?
simple columnar and in the intestine
What kind of epithelium has a brush border and where is it located?
simple cuboidal and in the kidney tubules
Where is a few examples of where heavily keratinized stratified squamous is found?
Epidermis with connective tissue papillae
Cornea without connective tissue papillae
Does heavily keratinized squamous epithelium in the cornea have connective tissue papillae?
No, only in the epidermis.
What type of epithelium is found in the lining of the mouth, tongue, and part of the epiglottis?
lightly or non-keratinized squamous epithelium
What type of epithelium can sometimes be found in small areas of the anal mucosa, large excretory ducts of some glands, and part of the male urethra?
STRATIFIED CUBOIDAL EPITHELIUM
If stratified columnar epithelium were to be found, where would you expect to find it?
- ducts of adult sweat glands
- fornix of the conjuctiva of the eye
- parts of the male reproductive/urinary tract
- pharynx
- epiglottis
What apical domain modifications can be found on pseudostratified epithelium in the epididymis?
stereocilia
What structure in the body has ciliated pseudostratified columnar epithelium?
Trachea
What are the 3 functions of epithelial tissues?
- protection (especially stratified squamous epithelium)
- maintain concentration differences (tight barriers & leaky barriers)
- secretion or absorption (typically simple or pseudostratified)
Give two examples of epithelial tissue that has leaky barriers and then name the type of epithelium tissue these barriers would be found in.
*lining of gallbladder
*proximal convoluted portion of renal tubule
Would be found in simple columnar epithelium
True of False: the height of the cell often reflects the level of secretory or absorptive activity of epithelial tissue.
True
Does epithelium have vessels?
NO
