Epithelial

Question 1

Tissue term given by? was first seen in which animal group?

Answer 1

Bichat

tissue first appeared in coelentrates/cnidarians

Question 2

Histology term given by

Answer 2

Mayer

Question 3

Founder of histology

Answer 3

Malpighi

Question 4

Epithelium term given by

Answer 4

Ruysch

Question 5

Exception of nervous tissue when three germ layers are considered

Answer 5

MICROGLIA (mesodermal)

Question 6

epithelial tissue which is vascular

Answer 6

stria vascularis (cochlea of ear)

Question 7

fish scales are? (wrt tissue) can they be removed?
what about snake scales?
also, which epithelial tissue is present in human skin?

Answer 7

dermal. no, hence used to determine age of fish.
snake cells are epidermal.
Keratinised stratified squamous (compound)

Question 8

mostly cell junctions are found in which tissue

Answer 8

epithelial

Question 9

extracellular, living basement membrane is characteristic of epithelial tissue.
basement membrane is made of?

Answer 9

false.
extracellular, non living basement membrane is characteristic of epithelial tissue.
basement membrane is sandwiched between the epithelial and connective tissue and is made up of their respective cell products/ secretions giving the upper, thin basal lamina (glycoproteins and mucopolysaccharides) and lower, thick fibrous reticular layer (collagen and reticular fibres).

Question 10

thyroid follicular glands and gonads: which epithelium

Answer 10

cuboidal

Question 11

bronchi and trachea

Answer 11

ciliated pseudostratified columnar

Question 12

male’s urethra

Answer 12

non ciliated pseudostratified columnar

Question 13

ependymal

Answer 13

ciliated columnar

Question 14

simple tubular

Answer 14

crypts of leiberkuhn

Question 15

branched tubular

Answer 15

gastric and uterine

Question 16

compound tubular

Answer 16

brunners, mammary glands of protherans

Question 17

simple coiled tubular

Answer 17

sweat

Question 18

simple alveolar

Answer 18

cutaneous glands of frogs

Question 19

simple branched alveolar

Answer 19

sebaceous

Question 20

compound alveolar

Answer 20

sublingual, submandibular

Question 21

compund tubulo alveolar

Answer 21

pancreas, parotid, mammary

Question 22

zymogen granules are found in which of pancreas

Answer 22

secretions include enzymes, hence, exocrinal component i.e. pancreatic acini

Question 23

islets of langerhans form which component of pancreas

Answer 23

secrete hormones, hence, endocrinal part

Question 24

apocrine

Answer 24

mammary, axillary sweat

Question 25

holocrine

Answer 25

sebaceous

Question 26

merocrine

Answer 26

most sweat, digestive

Question 27

Urinary bladder, ureter, urethra

Answer 27

Transitional/Urothelium Superficial most layer: stratum corneum (outermost layer of skin which forms horns of some mammals) germinative layer: stratum germinatum/ stratum malpighi (columnar cells)

Question 28

Which junctions are always found on the top layer?

Answer 28

``` Zona occludens (tight junctions) "these junctions prevent leakage of substances across tissue and are observed in the apical part of the adjacent epithelial cells" ```

Question 29

Tight junctions and gap junction aka

Answer 29

Zona occludens and macula occludens (gap junctions are made up of protein sub units called connexons. these connexons help in transfer of ions, small molecules and sometimes even large molecules)

Question 30

Plasma membrane in apical parts of adjacent epithelial cells becomes tightly packed to form?

Answer 30

Tight junctions (Zona occludens)

Question 31

What is present just below tight junctions

Answer 31

adhering junctions/ intermediate junctions | perform the job of cementing cells together

Question 32

describe intermediate/adhering junctions

Answer 32

zonula adherens these are present immediately below tight junctions. the intercellular spaces contain low electron density fluid. there is a dense plaque like on the cytoplasmic site of each plasma membrane from which fine microfilaments of actin protein extend into the cytoplasm. there are no intracellular filaments in intermediate adhering junctions.

Question 33

2 major differences between Zonaula adherens and Macula adherens

Answer 33

Intermediate/adhering junctions versus Desmosomes 1) Intermediate adhering junctions do not possess intercellular filaments/protein, whereas intercellular proteins are present in desmosomes 2) Intracellular protein of intermediate adhering junctions: actin, while Desmosomes have non-actin (keratin like) protein intracellular filaments called tonofibrils. They are thicker and stronger.

Question 34

What do hemi-Desmosomes do?

Answer 34

hemi desmosomes are single sided desmosomes adn are hence quite similar to them, just that the thickness of the cell membrane is seen only on one side. more importantly, They connect the epithelial tissue to basement membrane

Question 35

Olfactory mucosa

Answer 35

Sensory epithelium (nose)

Question 36

Schneiderian membrane

Answer 36

Sensory epithelium (nasal canal)

Question 37

Myoepithelium does what? Seen in?

Answer 37

Contraction (mammary, sweat)

Question 38

Pigmented epithelium is found where?

Answer 38

Retina, iris

Question 39

Layers of diffusion boundary

Answer 39

Three: 1) endothelium 2) basement membrane 3) alveolar squamous epithelium

Question 40

Mesothelium refers to

Answer 40

Epithelium of visceral organs (SEROSA)

Question 41

Wall of alimentary canal has how many layers

Answer 41

Four: 1) serosa- Mesothelium 2) muscularis 3) sub mucosa- CT with blood nerves lymph (sometimes glands like duodenal/Brunner's) 4) mucosa- inner epithelium

Question 42

Mucosal epithelium refers to

Answer 42

Mucosa, i.e. , goblet cells which release mucus for lubrication

Question 43

Mention variations in mucosa in stomach and intestines

Answer 43

though in stomach, simple columnar and in small intestine, ciliated columnar are found certain structural variations are also detected. given as follows: Mucosal infoldings in stomach are known as RUGAE and act as gastric glands. Small Intestine has villi and microvilli to increase surface area, the valley of these villi have mucosal epithelium and glands- crypts of Lieberkuhn Also, SI has circular folds of mucus membrane: PLICAE CIRCULARIS/VALVE OF KERKING/VALVULAE CONNIVENTES

Question 44

Valves of Kreking, what relevance do they have wrt to epithelial tissue

Answer 44

They are circular folds of mucosal membrane found in small intestine.

Question 45

what part of the body is the first to face both internal and external environment?

Answer 45

epithelial tissue. present on the lining of any surface, external or internal.

Question 46

simple epithelium ncert function and structure

Answer 46

``` #made up of a single layer of cells, all of which rest on the basement membrane (contrast with compound epithelial tissue where only the first germinative layer is present on the basement membrane) #serves as a lining for body cavities, ducts and tubes #functions: filtration, exchange, secretion, absorption ```

Question 47

tesselated epithelium is a modification of?

Answer 47

simple squamous epithelium: flat, polyhedral with centrally placed nucleus. (named so due to their wavy/ irregular boundaries.)

Question 48

which epithelium is present as a lining of blood vessels, lymph vessels, heart, coelom, visceral organs? name these linings.

Answer 48

simple squamous. blood vessels: endothelium coelom/visceral organs: mesothelium in the histology of gut, serosa is the outermost layer which is made of mesothelium with some connective tissue, while the innermost layer lining the lumen of alimentary canal is mucosa. This layer forms irregular folds called rugae in the stomach and small finger like foldings called villi in the small intestine. The cells lining the villi produce numerous microscopic projections called microvilli giving a brush bordered appearance (increase SA). villi are supplied with a network of capillaries and a large lymph vessel called the lacteal. Mucosal epithelium has goblet cells which secrete mucus which helps in lubrication. Mucosa also forms glands in the stomach (gastric glands: branched tubular) and crypts in between the bases of villi in the intestine (crypts of lieberkuhn: simple tubular)