Lecture 37 - Specialized Tissues, Stem Cells, and Tissue Renewal I

Question 1

What are the general characteristics of stem cells? (5)

L37 S4

Answer 1

• not terminally differentiated
• divide without limit
• able to self renew
• can remain a stem cell or differentiate
• slow division

Question 2

What are the types of stem cells and what differentiates them

L37 S5

Answer 2

Totipotent:
-can give rise to all cell types including embryonic and extra embryonic

Pluripotent:
-can give rise to all embryonic and adult tissues

Multipotent:
-can give rise to all cell types of a given lineage in adult tissues only

Question 3

What is a founder stem cell?

L37 S11

Answer 3

• fixed number of cells
• have a fixed number of divisions
• controlled by short range signals
• define size of final structures
• gives rise to transit amplifying cells

Question 4

What are transit amplifying cells?

L37 S13

Answer 4

• mixed with founder stem cells
• divide frequently
• limited number of divisions
• transition between stem cell and differentiated cells

Question 5

What are the cell layers of the epidermis and what are the characteristics of each layer?

L37 S21-22

Answer 5

Basal cell layer:
-dividing cells of epidermis

Prickle cell layer:
-contain desmosomes and keratin filaments

Granular cell layer:
-form a waterproof barrier

Squame:

• flattened dead cells, densely packed with keratin
• no organelles
• slough off from surface of skin

Question 6

What is responsible for basal cells retaining their stem cell characteristics or differentiating?

L37 S25

Answer 6

• cells in contact with the basal lamina express more β1 integrin which is correlated with retention of stem cell characteristics
• cells that loss contact with the basal lamina differentiate