Physiology and Pharmacology of the Large Bowel Flashcards
If you had a small intestine dysfunction, what would the faeces appear like and why?
Large volume of faeces, because 70-80% of absorption occurs in the small intestine
If you had a large intestine dysfunction, what would the faeces appear like and why?
Moderate volume of faeces, because the small intestine can still function and do most reabsorption
What are the two types of movement, and describe them
Peristalsis: which helps move things in a single direction
Segmentation: involved in breaking things down to increase surface area
What is the Ileocecal valve? What is its function
A valve separating the small intestine from the large intestine. Prevents reflex back into the ileum
Outline the histology of the large intestine
Thick mucosa with deep crypts, but NO villi. There are NO paneth cells, but lots of goblet cells
What does the large intestine only secrete?
Mucus only
What does the large intestine mainly absorb?
Na, Cl, K, Water
What is the role of the Smpathetic “fight or flight” response on the gut?
Inhibits GIT peristalsis and contraction of the bladder and rectum
What is the role of Parasympathetic “rest and digestive” response on the gut?
Increases peristalsis
What is the innervation of the External Anal Sphincter? Is it under voluntary or involuntary control?
Pudendal nerve, under voluntary control
What are the two Irritable Bowel Disease conditions?
Crohn’s and Ulcerative Colitis
Arthritis is linked to which GI condition?
Ulcerative colitis
Describe how Sulphalazine works
It is DMARD prodrug, which breaks down into 5-ASA. Mechanism unclear, but possible immune function
What is Immodium’s trade name? What is its mechanism of action?
Loperamide, and an anti-diarrhoeal drug. Mew-opiod receptor agonist. Decreases peristalsis and increases transit time for more absorption
What is Codeine Phosphate’s mechanism of action?
Mew-opiod receptor agonist. Decreases peristalsis and increases transit time for more absorption
