Epithelia ans Stem Cells

Question 1

Describe respiratory and transitional epithelia.

Answer 1

Ciliated columnar pseudostratified with goblet cells.

Exclusively in excretory urine passages where epithelium becomes distended. Stratified squamous when stretched and stratified cuboidal when relaxed.

Question 2

What are the key characteristics of epithelia?

Answer 2

No connective tissue
Avascular - diffusion provides nutrients as blood vessels can’t pass through the BM separating vascular CT from epithelia.
Exist as sheets.
3 types (epidermis, mesothelium, endothelium).

Question 3

What are the control points for stem cells?

Answer 3

Division 
Daughter cell choice (Stem cell or TA) 
Division of TA 
Timing from basal layer exit
Differentiation.

Question 4

What are the main controls for differentiation?

Answer 4

Attachment 
B1 integrin 
Signaling pathways (wnt maintains stemness, notch inhibits)

Question 5

what is the main difference between asthma and COPD?

Answer 5

Asthma is inflammation in large conducting airways with no affect on ling parenchyma.

COPD affects lung parenchyma and small airways.

Question 6

What are the properties of a cardiac stem cell?

Answer 6

Self renewal

Clonigenicity (must give rise to a colony of same cells)

Multipotency - give rise to differentiated cells of cardiac lineage e.g. cardiomyocytes, SM, endothelial, fibroblasts.

Question 7

what is cell passaging?

Answer 7

transfer some / all cells from previous culture to fresh growth medium, prolonging life and expanding number of cells.