Lect 1 - Epithelia

Question 1

define epithelial cells

Answer 1

Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands.

Question 2

glandular

Answer 2

it is glandular meaning that it can excrete and secrete material not related to its own metabolic needs

Question 3

simple v stratified

Answer 3

simple - single

strat - many of them together

Question 4

describe simple squamous epithelium, what are it main fucntions

Answer 4

squamous epithelium cells (aka pavement epithelium) are flat, wider than it is tall. this makes these cells excellent at exchanging stuff.

1. diffusion - e.g. lungs
2. filtration - e.g. kidneys
3. secretion - e.g. pleural, pericardial, peritoneal cavities

Question 5

describe simple cuboidal epithelium, what are it main fucntions

Answer 5

these cells are as wide as deep. they are good at secretion and absorption, and protection.

absorption - e.g. lining of kidney ducts
secretory - e.g. saliva and pacreas

Question 6

describe simple columnar epithelium, what are it main fucntions

Answer 6

these cells are taller than wide, with nucleus located near the base. they can be ciliated and non-ciliated
specialised fucntions get extra bits

in addition absorption, secretion, and protection, ciliated cells also facilitate transportation

e.g. gall bladder
sits on basil membrane

Question 7

where are simple columnar ciliated epithelium cell found

Answer 7

fallopian tubes

Question 8

why would simple columnar with microvilli

be useful

Answer 8

microvilli are tiny bunched up projection that increase the relative surface of cells

this is especially useful for absorption. it is mostly found in small and large intestines

Question 9

what is the role of glycocalyx

Answer 9

extracellular material on the apical side of microvilli that provides additional surface for adsorption and includes enzymes secreted by the absorptive cells that are essential for the final steps of digestion of proteins and sugars.

Question 10

compare nonmotile and motile processes

Answer 10

nonmotile - cytoplasmic projections that increase SA of cells and facilitate transport in and out of the cell. e.g. taste buds, inner ear

motile - cilia and flagella. facilitate movement of extracellular material

Question 11

whats a goblet cell

Answer 11

these are modified columnar cells that synthesise and secrete mucus.

they have nucleus at base, and mucigen granules at the apex

they’re mainly found in the small and large intestines

Question 12

describe pseudostratified ciliated

columnar epithelium, where are they found

Answer 12

looks like more than 1 layer of cell, all cells reset on the basement membrane but nuclei are on different levels

primarily found in bronchus

responsible for secretion lububrication, protecting, and transport

Question 13

describe stratified squamous epithelium, what do they do

Answer 13

made up of 2 more more layers of squamous cell

they mostly serve protective purpose

Question 14

what are desmosomes (macula adherens)

Answer 14

dense regions of attachment between cells

strong bonds

Question 15

describe stratified cuboidal epithelium, where are they usually found

Answer 15

2 or 3 layers of cuboidal epithelium
not much absorption or secretion

usually found in the larger duction of exocrine, e.g. salivary glands

Question 16

describe stratified columnar epithelium, where are they usually found

Answer 16

this is made from several layers of epithelial cells of which the surface layer is columnar cells

their role is to protect and secrete

they are only found in male urethra and portion of the conjunctiva

Question 17

describe transitional (urothelial) epithelium, where are they usually found

Answer 17

this is the intermediate transition between stratified cuboidal and stratified squamous

4 to 5 layers of cell
basal layer is cuboidal, surface is large and rounded

protective and distensible
e.g. bladder

Question 18

differentiate between unicellular and multicellular glandular epithelium

Answer 18

unicellular - goblet

multicellular - endo/exocrine glands

Question 19

what are the differences between endocrine and exocrine glands

Answer 19

endo - products (hormones) are secreted directly into the blood

exo - products are release onto free surface of skin or open cavities. e.g. sweat glands, salibary glands

Question 20

functions of epithelium, and where are they found

Answer 20

• Diffusion - alveoli of lungs
• Barrier - skin
• Containment- endothelium - blood-brain barrier
• Excretion- collecting ducts of kidney
• Secretion - breast (milk),skin (sweat) and
gastrointestinal tract (mucous), pancreas (hormones)
• Absorption - small intestine
• Contractility - bladder, salivary glands
• Sensation - taste buds, olfactory epithelium

Question 21

differentiate between keratising and nonkeratinising squamous epithelium

Answer 21

keratin - tough protective protein which prevents water loss, resistant to friction, and repels bacteria

keratinising - epidermis of skin
non-keratinising - mouth, vagina, esophagus