Epithelial Tissues V

Question 1

epithelial stem cells are capable of _______ and serve to _______ and _______

Answer 1

• cell division
• self renew
• produce differentiated cell types specific to each epithelia

Question 2

stem cells produce differentiated cell bypes by

Answer 2

cell division coupled with specific pathways of cell specification imposed on some of their daughter cells

Question 3

transit amplifying cells

Answer 3

transitional intermediates (daughter cells of stem cells that proliferate themselves at faster rates) which produce differentiated cells

Question 4

The _______ of stem cells determines the constellation of cell types, their relative proportions and their arrangements

Answer 4

developmental state

Question 5

cell lineage

Answer 5

specific stem cell type, its intermediate progeny and their differentiated progeny

Question 6

both division and differentiation in stem cell lineages are tightly regulated by _______ and _______ which are activated or inhibited by _______

Answer 6

• cell to cell communication
• cell signaling pathways
• physiological and developmental cues

Question 7

stem cells tend to divide

Answer 7

very slowly, sot hey are usually much less abundant than their differentiated offspring

Question 8

what is generally at the heart of many stem cell diseases?

Answer 8

loss of regulation

Question 9

typical cell signally pathway consists of

Answer 9

(1) excell ligand (secreted by signaling cells)
(2) receptor (act/inact by ligand)
(3) downstream effector proteins (in cyto or nuc)
(4) numerous modulator proteins (promote/suppress pathway components)

Question 10

long distance signals are typically secreted from ______ or may be produced by the ______

Answer 10

• endocrine glands into the blood stream

- NS or other tissues

Question 11

signaling pathways include

Answer 11

Wnt, Sonic hedgehog, TGFb, Notch, RTK and FGF

Question 12

Each pathway is used by _______. Although some pathway proteins may be unique to certain stem cell subsets, most pathway components are shared by several distinct stem cell lineages

Answer 12

multiple, very distinct stem cell systems in different organs/tissues

Question 13

(i) Each pathway is used by multiple, very distinct stem cell systems in different organs/tissues. Although some pathway proteins may be unique to certain stem cell subsets, most pathway components are _______

Answer 13

shared by several distinct stem cell lineages (stem cell lineages=stem cells and all their daughters, granddaughters, etc)

Question 14

A single signaling pathway often triggers different developmental outcomes in different stem cell lineages. These differences result from combinations of:

Answer 14

(a) Different developmental histories of each stem cell type (cells can inherit and maintain unique differences which dramatically impact how a cell responds to a ligand)
(b) Different environments stem cells reside in (the different combos of signaling inputs a cell is exposed to).
(c) Differences in the levels of the extracellular ligands, receptors, and/or downstream components.

Question 15

pathways are prime targets for

Answer 15

drug therapies

Question 16

Tarceva (erlotinib)

Answer 16

activates EGF receptor and is commonly used to treat lung and pancreatic cancers