Block 2 - Integration

Question 1

The major stimulus of pancreatic zymogen secretion is…

Answer 1

CCK from duodenal I-cells

Question 2

The major stimulus of pancreatic secretion of NaHCO3 and water is…

Answer 2

secretin released from duodenal S-cells

Question 3

Failure of CFTR in pancreatic duct cells results in…

Answer 3

decreased recycling of Cl- across the luminal membrane, leading to the net loss of luminal Cl- and the subsequent inhibition of apical Cl/HCO3 exchange

Question 4

The predominant chloride channel in pancreatic acinar cells is _________ whereas the predominant chloride channel in pancreatic duct cells is _________

Answer 4

CLCA

CFTR

Question 5

What are the main 3 clinical presentations of cystic fibrosis?

Answer 5

• high Cl- concentration
• some form of malnourishment
• chronic pulmonary disease

Question 6

CFTR is a type of —- channel

Answer 6

Cl-

Question 7

Is the acinus, duct, or both affected by CF? Why? How does this create malnourishment issues?

Answer 7

duct, because CFTR is in the duct

acinar cells release zymogens but the duct cells dont release enough NaHCO3 fluid, so food is not digested as well

Question 8

How is chronic pulmonary disease caused by CF?

Answer 8

ENaC causes Na influx, which is normally balanced by CFTR Cl efflux

In CF (when CFTR doesn’t work and ENaC is upregulated) Cl also moves in with Na at increased rates
This causes less ASF to be produced and mucus becomes thick and stagnant which provides a breeding ground for bacterial colonizations

Question 9

What are the three main treatment strategies for CF’s affects on the airway?

Answer 9

• gene therapy
• inhibition of ENaC
• pharmacological repair of mutant CFTR

Question 10

Why does CF have so much physiologic influence when it only changes on transporter?

Answer 10

flux of Cl- is involved in many processes, it is the major anion in extracellular fluid, also affects processes involving Na+ and water