Cell differentiation (continued)

Question 1

Which cell type Forms crypts and Villi in the human colon?

Answer 1

Columnar epithelial cells.

Question 2

Which type of cells are found at the bottom of crypts?

Answer 2

Stem cells.

Question 3

What are Colonocytes?

Answer 3

Absorptive epithelial cells.

Question 4

What are Goblet cells?

Answer 4

Mucus secreting cells.

Question 5

What are entero-endocrine cells?

Answer 5

Peptide-hormone secreting cells.

Question 6

What are paneth cells?

Answer 6

Antimicrobial-peptide secreting cells.
Also perform phagocytosis and efferocytosis.
Take up heavy metals.
Preserve barrier integrity.

Question 7

How is proliferation regulated in the human colon?

Answer 7

Controlled by +wnt ligands.
+Wnt comes from paneth cells at the bottom of crypts.
Not present at top (no proliferation).
Higher up the crypt means more differentiated but less proliferated.

Question 8

How is differentiation regulated in the human colon?

Answer 8

Notch signalling -
Notch on:
Wnt low = notch on.
absorptive fate.
Generates enterocytes and M-cells.
Notch off:
Wnt high = notch off.
Secretory fate.
Tuft, Goblet, Paneth and entero-endocrine cells formed.