Case 3 - PBL

Question 1

describe and explain the process of fat absorption

Answer 1

the bile micelle, which develop during digestion of fats, are soluble in chyme because of their size and their highly charged exterior

In this form, the monoglycerides and free fatty acids are carried to the surfaces of the microvilli of the intestinal cell brush border and then penetrate into the recesses among the moving, agitating microvilli

Here, both the monoglycerides and fatty acids diffuse immediately out of the micelles and into the interior of the epithelial cells, which is possible because the lipids are also soluble in the epithelial cell membrane

This leaves the bile micelles still in the chyme, where they function again and again to help absorb still more monolglycerides and fatty acids - ‘a ferrying function’

After entering the epithelial cell, the fatty acids and monoglycerides are taken up by the cell’s smooth endoplasmic reticulum; here they are mainly used to form new triglycerides that are subsequently released in the form of chylomicrons

These chylomicrons are exocytosed through the base of the epithelial cell, and are transported in the lymphatic system to the liver

Question 2

what happens to small quantities of short and medium fat chain acids

Answer 2

are absorbed directly into the portal blood rather than being converted into triglycerides and absorbed by the way of the lymphatics

Question 3

why is this

Answer 3

because the short chain fatty acids are more water soluble and mostly are not reconverted into triglycerides by the endoplasmic reticulum

Question 4

what does this allow

Answer 4

allows direct diffusion of these short chain fatty acids from the intestinal epithelial cells directly into the capillary blood of the intestinal villi

Question 5

effect drugs have on pancreatic vs gastric dysfunction

Answer 5

stomach disorders lead to imbalances in acid secretion
Therefore, drugs that act on acids (antacids) or acid secretion (PPIs/H2 antagonists etc) would be effective in gastric dysfunction
However if it is pancreatic dysfunction then such drugs have little effect

Question 6

how does pain differentiate in pancreatitis vs gastritis

Answer 6

In pancreatitis, the pain is usually referred to the back of the body too, whereas with gastric pain the pain is localised to the epigastrium
Analgesics and NSAIDs have little effect in visceral pain, but they are efficient for somatic pain