Epithelial Cells And Tissues

Question 1

What is tissue

Answer 1

Groups of cells with distinct structures consisting of extra cellular matrix cells and fluid

Question 2

Extracellular matrix

Answer 2

Contains fibrillar proteins held in hydrated gel substance

Question 3

5 main cell types

Answer 3

Connective tissue
Contractile tissue eg fibroblasts osteocytes
Haematopoietic cells eg skeletal,cardiac,smooth
Epithelial cells
Neural cells eg neurons and glial cells

Question 4

Simple squamous epithelium

Answer 4

Found in air sacs
Mesothelium-lines major body cavities
Endothelium-lines blood vessels
They are thin allowing gas exchange

Question 5

Simple cuboidal

Answer 5

Found in ducts

Question 6

Simple columnar

Answer 6

Involved in absorption and secretion

Question 7

Stratified squamous

Answer 7

Keratinising: Produce keratin which when they die become thicker and stronger structures. Lose organelles and nuclei
Non keratinising: retain nucleus and organelles eg anus cervix aging oesiphagus

Question 8

Pseudo stratified

Answer 8

Epithelium looks multi layered but only surface has contact with basal lamina
Eg ducts in urinary and reproductive tracts

Question 9

Tight junctions

Answer 9

Found in apical lateral membrane
Seals gaps between cells

Question 10

Adhering junctions

Answer 10

Master junction which controls formation of other junctions

Question 11

Desmosomes

Answer 11

Spot junctions
Form tight junctions between cells.
Important in cells that require resistance to mechanical stress

Question 12

Gap junctions

Answer 12

Channel forming junctions
Form pores between cells
Allow exchange and sharing of materials

Question 13

Transporting epithelia

Answer 13

Plasma membranes contain high concentrations of ion transporters

Mitochondria are highly associated with basolateral surface of epithelium to provide ATP for active transport across basal lamina

Because active transport is confined to basal membranes, ion and water transport will have directionality

Question 14

Absorptive epithelium

Answer 14

Villi are arranged in finger like projections
Microvilli increase surface area further
Secretory cells are interspersed among absorptive cells of intestinal villi
Brush border is rich in active transporters

Question 15

Secretory epithelium

Answer 15

Endocrine secrets into blood
Exocrine secretes into ducts or lumen
Acccumulation at apical membrane means secretion into ducts so exocrine
Accumulation at basolateral membrane means secretion into circulation so endocrine

Question 16

Cancers from cells

Answer 16

Epithelial= carcinomas
Mesenchymal=sarcomas
Haematopoeitic=leukemia or lymphomas
Neural cells=neuroblastimas or gliomas

Question 17

Transporter epithelia polarized vs unpolarised

Answer 17

In unpolarised there is passive movement of ions into and out of cell so no net flow
In polarised we get directional flow

Question 18

Exicrine vs endocrine

Answer 18

Endocrine secrete into capillary

Question 19

What does chemo do

Answer 19

Can cause the loss of intestinal villi causing gastrointestinal disturbances

Question 20

Increased cell proliferation

Answer 20

Causes benign tumors (polyp)

Question 21

Hyperproliferation

Answer 21

Causes thickening of cell layers. Can also be caused by viruses such has papiloma virus