Epithelial cells

Question 1

Apical-basal polarity

Answer 1

polarity = positioning of the cell, the cell has an apical and basal surface and will always face accordingly (basal towards basement membrane)

Question 2

blood vessels in epithelial tissue

Answer 2

avascular - uses diffusion through basement membrane to obtain nutrients from connective tissue

Question 3

endothelium vs mesothelium

Answer 3

endo = epithelium which lines the inner surface of BVs, lymph vessels, heart -> from endoderm

meso = epithelium which lines peritoneum, pleura, percardium -> from mesoderm

Question 4

How to define stratified tissue by cell type

Answer 4

Define by the shape of the cells at the surface

Question 5

Mucosa vs serosa

Answer 5

epithelium and connective tissue relationship which lines organs

mucosa - lines the inner surface/lumen
serosa - lines the outer free surface of organ

Question 6

‘anexome’

Answer 6

the arrangement of microtubules in cilia

9+2 arrangement

Question 7

Desmosome

Answer 7

strong attachment site between cells
attaches to intermediate filaments in cells
involves the interactions/interdigitations of ‘cadherins’

Question 8

Hemidesmosome

Answer 8

structural attachment of epithelial basal layer to the basement membrane

Question 9

Simple squamous epithelium

Answer 9

Location: lines areas where passive diffusion of gases occur (e.g. alveoli)
Function: diffusion, absorption

Question 10

simple cuboidal epithelium

Answer 10

Location: glands, ducts, kidney tubules
Function: secretion, absorption

Question 11

Simple columnar epithelium

Answer 11

Location: respiratory tracy, uterus, stomach, small intestine
Function: have extensions
- cilia: movement of oocyte in ovary, particles in lungs
- microvilli: absorption in stomach, small intestine

Question 12

Stratified squamous epithelium

Answer 12

Location: mouth, anus, vagina, palms, sole of feet
Function: protection against abrasion, infection

Question 13

Stratified cuboidal epithelium

Answer 13

Location: Salivary glands, sweat glands
Function: absorption, secretion, protect against infection

Question 14

Pseudostratified columnar epithelium

Answer 14

Location: trachea, bronchi, fallopian tubes
Function: have extensions such as cilia which move particles and ovum. also synthesises and secretes mucous

Question 15

Transitional epithelium

Answer 15

Location: urinary tract
Function: accommodates the fluctuations of the vessel size. Dome shaped cells which line lumen contain extra reservoir membrane to allow for stretching

Question 16

Cilia

Answer 16

Function for movement - move secretions, particles
Supported by microtubules which are arranged in an anexome = 9 pairs around the outside + 2 centrally
found on pseudostratified columnar
2-10um

Question 17

micro-villi

Answer 17

non motile, function to increase SA and help with absorption of nutrients in digestive system
supported by actin filaments in cytoplasm
1-3um

Question 18

sterocilia

Answer 18

long extensions, non motile, increase SA
found in epididymis to help with absorption of fluids, and are sensory cells of ear
25-120um
pseudostratified columnar

Question 19

Types of glands

Answer 19

exocrine = have ducts which are used to secret mucous or serous

endocrine = no ducts, just secrete directly into bloodstream (glands in close contact with BVs)

Question 20

Exocrine gland arrangements

Answer 20

alveolar (tear dropped) vs tubular
can be branched (becomes like a 4 leaf clover)
can be simple (single) or compound (a number of glands together)

Question 21

stratified epithelium will never have….

Answer 21

cilia