TYPES OF EPITHELIA

Question 1

what are the two forms of epithelial tissue

Answer 1

• epithelia covering external body and line internal surface
• glands (from invaginated epithelial cells)

Question 2

what is derived from

a) ectoderm
b) endoderm
c) mesoderm

Answer 2

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

Question 3

what are stratified epithelia classified by

Answer 3

morphology of the cells in their superficial layer

Question 4

where is Simple squamous epithelia found

Answer 4

• 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

Question 5

difference between cuboidal and columnar epithelium

Answer 5

cuboidal - centrally placed round nucleus, square

columnar- oval nuclei, rectangular, nucleus at base

Question 6

where is cuboidal epithelium found

Answer 6

• ducts of glands
• covering of the ovary
• kidney tubules

Question 7

where is Simple columnar epithelium found

Answer 7

• stomach
• gallbladder
• large ducts of glands

Question 8

where is simple columnar cilated epithelium found

Answer 8

uterus, oviducts, ductuli efferentes and small bronchi

Question 9

describe Stratified squamous (nonkeratinized) epithelium

Answer 9

base- columnar, cuboidal
middle- polymorphous
free surface- squamous

Question 10

why are Stratified squamous (nonkeratinized) epithelium called non-keratinized

Answer 10

Because the surface cells are nucleated

Question 11

where is Stratified squamous (nonkeratinized) epithelium found

Answer 11

mouth, oral pharynx, esophagus, true vocal folds, and vagina

Question 12

how is Stratified squamous (keratinized) epithelium different from stratified squamous (nonkeratinized) epithelium

Answer 12

superficial layers of the epithelium are composed of dead cells whose nuclei and cytoplasm have been replaced with keratin

Question 13

where is Stratified squamous (keratinized) epithelium found

Answer 13

epidermis of skin

Question 14

what is stratified squamous parakeratinized epithelium

Answer 14

its surface-most cells retain their nuclei, though they are pyknotic

Question 15

where is stratified squamous parakeratinized epithelium found

Answer 15

hard palate and gingiva

Question 16

describe the structure of Stratified cuboidal epithelium and where is it found

Answer 16

contains only two layers of cuboidal cells, lines the ducts of sweat glands

Question 17

structure of Stratified columnar epithelium

Answer 17

low polyhedral to cuboidal deeper layer and superficial layer of columnar

Question 18

where is structure of Stratified columnar epithelium found

Answer 18

conjunctiva of the eye
large excretory ducts
male urethra

Question 19

what is transitional epithelia

Answer 19

transition between stratified columnar and stratified squamous epithelia

Question 20

where is transitional epithelia found

Answer 20

urinary system, lining urinary tract from the renal calyces to the urethra

Question 21

structure of transitional epithelia

Answer 21

• basally- low columnar or cuboidal cells
• above base- polyhedral cells
• superficial cells- large, binucleated, dome tops bulging into lumen

Question 22

what is the most widespread type of pseudostratified columnar epithelium

Answer 22

ciliated

Question 23

where is • Pseudostratified ciliated columnar epithelium found

Answer 23

trachea and primary bronchi, the auditory tube, part of the tympanic cavity, the nasal cavity, and the lacrimal sac

Question 24

where is Pseudostratified columnar epithelium with stereocilia found

Answer 24

male urethra, epididymis, and larger excretory ducts of glands

Question 25

what happens during vitamin A deficiency

Answer 25

epithelial tissues in bronchi and urinary bladder replaced by stratified squamous epithelium

Question 26

what happens in chronic bronchitis in smokers

Answer 26

no. of goblet cells in airways increases–excessive mucus production and obstruction of airways

Question 27

how is ciliated pseudostratified epithelium lining of bronchi.

Answer 27

it is transformed into stratified squamous epithelium by metaplasia