TYPES OF EPITHELIA Flashcards
what are the two forms of epithelial tissue
- epithelia covering external body and line internal surface
- glands (from invaginated epithelial cells)
what is derived from
a) ectoderm
b) endoderm
c) mesoderm
a) oral and nasal mucosae, the cornea, the epidermis of skin, and the glands of the skin and the mammary glands
b) liver, pancreas, and lining of the respiratory and gastrointestinal tract
c) uriniferous tubules of the kidney, the lining of the male and female reproductive systems, the endothelial lining of the circulatory system, and the mesothelium of the body cavities
what are stratified epithelia classified by
morphology of the cells in their superficial layer
where is Simple squamous epithelia found
- pulmonary alveoli
- loop of Henle and parietal layer of Bowman capsule
- endothelial lining of blood and lymph vessels
- mesothelium of the pleural, pericardial, and peritoneal cavities
difference between cuboidal and columnar epithelium
cuboidal - centrally placed round nucleus, square
columnar- oval nuclei, rectangular, nucleus at base
where is cuboidal epithelium found
- ducts of glands
- covering of the ovary
- kidney tubules
where is Simple columnar epithelium found
- stomach
- gallbladder
- large ducts of glands
where is simple columnar cilated epithelium found
uterus, oviducts, ductuli efferentes and small bronchi
describe Stratified squamous (nonkeratinized) epithelium
base- columnar, cuboidal
middle- polymorphous
free surface- squamous
why are Stratified squamous (nonkeratinized) epithelium called non-keratinized
Because the surface cells are nucleated
where is Stratified squamous (nonkeratinized) epithelium found
mouth, oral pharynx, esophagus, true vocal folds, and vagina
how is Stratified squamous (keratinized) epithelium different from stratified squamous (nonkeratinized) epithelium
superficial layers of the epithelium are composed of dead cells whose nuclei and cytoplasm have been replaced with keratin
where is Stratified squamous (keratinized) epithelium found
epidermis of skin
what is stratified squamous parakeratinized epithelium
its surface-most cells retain their nuclei, though they are pyknotic
where is stratified squamous parakeratinized epithelium found
hard palate and gingiva
describe the structure of Stratified cuboidal epithelium and where is it found
contains only two layers of cuboidal cells, lines the ducts of sweat glands
structure of Stratified columnar epithelium
low polyhedral to cuboidal deeper layer and superficial layer of columnar
where is structure of Stratified columnar epithelium found
conjunctiva of the eye
large excretory ducts
male urethra
what is transitional epithelia
transition between stratified columnar and stratified squamous epithelia
where is transitional epithelia found
urinary system, lining urinary tract from the renal calyces to the urethra
structure of transitional epithelia
- basally- low columnar or cuboidal cells
- above base- polyhedral cells
- superficial cells- large, binucleated, dome tops bulging into lumen
what is the most widespread type of pseudostratified columnar epithelium
ciliated
where is • Pseudostratified ciliated columnar epithelium found
trachea and primary bronchi, the auditory tube, part of the tympanic cavity, the nasal cavity, and the lacrimal sac
where is Pseudostratified columnar epithelium with stereocilia found
male urethra, epididymis, and larger excretory ducts of glands
what happens during vitamin A deficiency
epithelial tissues in bronchi and urinary bladder replaced by stratified squamous epithelium
what happens in chronic bronchitis in smokers
no. of goblet cells in airways increases–excessive mucus production and obstruction of airways
how is ciliated pseudostratified epithelium lining of bronchi.
it is transformed into stratified squamous epithelium by metaplasia
