Introductory lecture

Question 1

What are the three functions of the GI tract?

Answer 1

1. Ingestion
2. Mechanical processing
3. Digestion

Question 2

What does the peritoneum secrete?

Answer 2

Peritoneal fluid for lubrication as the organs move against each other

Question 3

What is the purpose of fat around organs?

Answer 3

Cushioning and protection

Question 4

Where does all blood from the GI tract go?

Answer 4

To the liver via the portal vein

Question 5

What is the arterial blood supply of the liver?

Answer 5

Hepatic artery

Question 6

What is the serosa continuous with in the GI tract?

Answer 6

Visceral peritoneum

Question 7

What six types of junctions are present between cells in the GI tract?

Answer 7

Tight (occluding) junction
Adherens junction (connects 2 cells by actin filaments)
Desmosome (connets 2 cells by intermediate filaments)

Gap junction (channel)

Hemidesmosome (connect cell to basal lamina with intermediate filaments)
Actin filament (connects cell to basal lamina)

Question 8

What is Jnet?

Answer 8

Net flow (absorption-secretion)

Question 9

What are the three types of transport?

Answer 9

1. Passive
2. Primary active transport (ATP)
3. Secondary active transport (uses energy from electrochemical gradient for one substrate and the second substrate moves against the electrochemical gradient e.g. Na+/glucose transporter)

Question 10

What effect does sympathetic stimulation have on gut activity?

Answer 10

Reduces gut activity

Question 11

What are the two plexi involved in enteric NS of the gut?

Answer 11

Myenteric and submucosal

Question 12

What are ICCs and what do they do?

Answer 12

Interstitial Cells of Cajan, they are like pacemakers and initiate an underlying ‘beat’ of the GI tract 3-12 times a minute