epithelial tissue

Question 1

who coined the term epithelium ?

Answer 1

Ruysch

Question 2

what is epithelium?

Answer 2

epithelium is made up of one layer or more than one layer of cells, they cover or lines organs and other external and infernal parts of the body.

Question 3

explain the the structure of epithelial tissues?

Answer 3

they are made up of variously shaped cells closely arranges with very little intercellular material.it has one or more than one layer.it consists of a basal surface which lies on the basement membrane and free surface which faces the body fluid or outside environment and thus proving a protecting covering

Question 4

what is basement membrane and explain its function?

Answer 4

basement membrane is a non- cellular layer which is responsible for providing elastic support to the epithelial cell and also anchors it to the underlying connective tissue for obtaining nutrients

Question 5

what are the main two groups of epithelial tissue?`

Answer 5

simple epithelium and compound epithelium

Question 6

whaat are the 6 types of simple epithelial tissue?

Answer 6

1) squamous
2) cuboidal
3) columnar
4) glandular
5) pseudo stratified
6) ciliated

Question 7

explain the structure of squamous epithelium?

Answer 7

they are closely fitted thin flat cell with irregular boundaries .but from the surface they look polygonal they are also called pavement cells. They have a flat thin centrally located nuclei

Question 8

where are squamous epithelial cells located?

Answer 8

inner blood vessels(endothelium).Bowman’s capsule, Loop of Henle, lymph vessels, coelomic cavity, alveoli

Question 9

what are the functions of epithelial tissue?

Answer 9

since they are thin its easier for particles to pass-through

1) they help is filtration in Bowman’s capsule
2) exchange of material between blood capillaries and tissue fluid
3) exchange of gases in alveoli

Question 10

explain the structure of cuboidal epithelium?

Answer 10

it consists of cube shaped cells that has a centrally located round nuclei.the free surface are either smooth or has microvilli wich increases the area of absorption.cuboidal epithelium with micro villi are called brush bodered epithelium

Question 11

where are cuboidal epithelium located?

Answer 11

they are located in :

1) ducts of glands, thyroid follicles
2) ovaries and testis (germinal epithelium
3) PCT of nephron(brush bordered epithelium)

Question 12

functions of cuboidal epithelium?

Answer 12

1) selective reabsorption in PCT

2) SECRETION AND excretion by glands

Question 13

what is germinal epithelium?

Answer 13

they are cuboidal epithelium present in ovaries and seminiferous tubules of testes, they produce gametes , ova and sperms

Question 14

explain structure of columnar epithelium?

Answer 14

they are tall and slender cellls. the nuclei is elongated along the long axis and is present near the base of the cell. their free surface can be smooth or can have microvilli. some columnar cells produce mucus(goblet cell)

Question 15

what are mucosa?

Answer 15

they are mucus producing epithelium with underlying connective tissue

Question 16

what are brush bordered columnar epithelium?

Answer 16

they are intestinal mucosa with micro villi .

Question 17

where is columnar epithelium located?

Answer 17

lining of stomach and intestine., gall bladder , bile duct pancreatic lobules

Question 18

what are the functions of columnar epithelium?

Answer 18

secretion and absorption.

Question 19

what are ciliated epithelium and explain its structure?

Answer 19

they are cuboidal or columnar cell that bear cilia(hair-like outgrowth).the cilia stays in a rhythmic motion to create a current that moves materials in contact to a specific direction.

Question 20

where are ciliated epithelium located?

Answer 20

cuboidal: - smaller bronchioles, nephrons
columnar: -fallopian tube, most of the respiratory tract., ventricles of the brain, lymphatic tube cavity of the middle ear, the central canal of the spinal cord, eustachian tube

Question 21

what are the functions of ciliated epithelium?

Answer 21

1) in fallopian tube they help in the passage of ovum through the fallopian tube.
2) they help in the expelling of mucus and other particles present in the respiratory tract, towards pharynx.

Question 22

what are mucus producing columnar epithelium called?

Answer 22

goblet cells

Question 23

what are pseudostratified epithelium?

Answer 23

they are single layered epithelium whose nuclei is positioned in a manner that makes it look like stratified epithelia.

Question 24

explain the structure of pseudostratified epithelium?

Answer 24

they are columnar cell but in unequal sizes, the t long cell extend upto the free surface and has oval nuclei. the short cells do not reach the outer free surface and has round nuclei .the nuclei lie at different levels making it look stratified ,and thus giving it the name pseudostratified epithelium. goblet cells also occur in this epithelium

Question 25

where are pseudostratified epithelium located?

Answer 25

non ciliated: urethra of males

ciliated: large bronchi and trachea

Question 26

what are glandular epithelium?

Answer 26

they are epithelium that get specialized for secretion, cells of glandular epithelium are columnar or cuboidal in outline.the glands are formed from glandular epithelium n. glands may be made up of a cell,tissue or organ.

Question 27

what are glands classified into on the bases of mode of secretion?

Answer 27

glands are classified into :
1)endocrine gland: they are ductless glands that secret products(hormones) directly into the fluid the bathing the gland i.e blood and lymph. blood and lymph caries the hormones to the target organ.eg: thyroid, adrenal, hypothalamus , pituitary .

2) exocrine: they drain out their secretion to the body surface through a duct or pours directly over the substrate. exocrine glands secret mucus saliva ,earwax, oil , milk , digestive enzymes and other cell products. eg: salivary gland, gastric gland , mammary gland etc.

Question 28

what are compound epithelium?

Answer 28

they are epithelium that consists more than on layer. they are responsible for protection of underlying tissues from mechanical, chemical and thermal or osmotic stress.

Question 29

what are the two parts of a compound epithelium?

Answer 29

stratum cornea and stratum germinativum

Question 30

what are the 2 types of compound epithelium?

Answer 30

stratified epithelium and transitional epithelium

Question 31

what are the different types of stratified epithelium?

Answer 31

1) stratified cuboidal-e.g.: large salivary ducts
2) non keratinized squamous(squamous + cuboidal):
e. g.- buccal cavity , tongue , pharynx , oesophagus.
3) keratinized stratified squamous : epidermis of land vertebrates

Question 32

what are transitional epithelium?

Answer 32

1) its thinner and more stretchable that stratified epithelium
2) it has single layer of cuboidal cells at the base
3) 2-3 middle layers made up of polygonal or pear shaped cells
4) superficial; layer of large broad oval or rectangular cells.
5) lack basement membrane
6) eg; inner surface of urinary bladder and ureter.(urothethelieum) considerable expansions of these organs allows to accommodate urine, because stretching considerably flattens and broadens the cells of superficial and middle layer

Question 33

what are glands classified into based on secretory and ducts part?

Answer 33

1) tubular

2) alveolar /saccular gland

Question 34

what are tubular g;ands?

Answer 34

1) simple tubular: eg crpts of leiberkuhn
2) simple coiled tubular : sweat glands
3) simple branched tubular glands: gastric gland
4) compound tubular: mammary gland of oviparous mammal

Question 35

what are alveolar glands / saccular glands?

Answer 35

1) simple alveolar: skin gland of frogs, poison gland of toads.
2) simple branched alveolar: sebaceous gland
3) compound alveolar: sublingual and submandibular salivary glands
4) compound tubular alveolar gland : parotid gland, mammary gland of humans

Question 36

what are the 3 types of glands based on secretion?

Answer 36

1) merocrine gland cells: pancreas, gastric, sweat salivary
2) apocrine cells: mammary gland humans.
3) holocrine cells: sebaceous gland

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