GI Tract: Intestine and Colon

Question 1

Gallstones pathogenesis:

Answer 1

• Chronic hemolysis (overload the ability of the enzyme in the liver to conjugate it –> increase unconjugated bilirubin)
• Excess of cholesterol secreted in the bile –> obesity
• Very rapid weight loss

Question 2

Volvulus:

Answer 2

• Intestinal obstruction where there is a twisting of the intestine that can come free and twist on itself.
• Absorption won’t be taking place very well, it can’t move forward.

Question 3

Intussusception:

Answer 3

-Intestinal obstruction where one part of the intestine is pulled into the next part.

Question 4

Intestinal obstruction causes:

Answer 4

Mechanical causes:

• Volvulus
• Herniation
• Adhesions
• Intussusception

Question 5

Paralytic Ileus:

Answer 5

• After surgery, release a lot of cytokines and result in paralysis of peristalsis
• Loss of neurons which will cause obstruction due to non peristalsis (ANS)

Question 6

Diverticulosis:

Answer 6

• Low fiber diet cause more pressure in the intestine and tends to push this out causing pouches.
• Can infect –> diverticulitis

Question 7

Crohn’s disease:

Answer 7

• Transmural inflammation

- Cobblestone appearance

Question 8

Ulcerative colitis:

Answer 8

• Ulcer in the colon
• Mucosa destroyed with granulation tissue at the base of these ulcers
• Survival mucosa look like pseudopolyps

Question 9

Secretory diarrhea:

Answer 9

• Secreting much mor that you’re able to absorbe

- Due to excess input of electrolytes (NaCl) with the water following.

Question 10

Osmotic diarrhea:

Answer 10

• Happen to people who are intolerant to lactose
• Bacteria grow on it more than normally would (due to lactose not absorbed–>no lactase) and will causes water to be retained due to osmosis.

Question 11

Diarrhea causes:

Answer 11

Osmotic
Decreased absorption
Increased secretion

Question 12

Diarrhea consequences:

Answer 12

Hypovolemia
Loss of K
Acidosis (loss of alkali from intestines)
Malnutrition (chronic)

Question 13

Cholera:

Answer 13

-Cause diarrhea due to Vibrio cholerae produce a toxin which inserts in cell membranes in the intestine , causing G-proteins to be trapped in “ON” configuration, yielding sustained 2e messenger production. (will cause the cells pump out sodium and chloride, and water follow)

Question 14

Oral rehydratation theray:

Answer 14

• Contains glucose (coupled with Na in terms of absorption system in the intestine, so increase the sodium absorption –> water will follow)
• Electrolytes

Question 15

Rotavirus:

Answer 15

• The virus will damaged the villi, causing malabsorption
• Will increase secretion and impairs absorption, cause cell lysis
• damage the epithelial lining , which is where lactase is made –> can be intolerant to lactose for weeks.

Question 16

Norovirus:

Answer 16

• Principal virus causing food poisoning, has antigen drift component. (so never immune, due to his frequent change)
• 24-48h
• Villus destruction and lactose intolerance

Question 17

Salmonella:

Answer 17

• Bacteria causing food poisoning.
• Alter the normal microbiome in your intestine. Able to cross the intestinal barrier.
• Causing inflammatory diarrhea

Question 18

Staphlococci:

Answer 18

• Bacteria that is a normal constituents on humans that caused food poisonning.
• Human touching the food anf the bacteria will grow on the food and release toxin
• Pre-formed, heat stable enterotoxin (even if heat or cook, still releasing their toxins)

Question 19

E. coli:

Answer 19

• Major subgroups
• Enterotoxigenic E. coli (ETEC) cause gastroenteritis
• It increase secretion by stimulate a receptor which increase the output of sodium and chloride along with water.

Question 20

0157:H7 strain of E. coli:

Answer 20

• Cytotoxic and makes Shiga toxins

- Entero hemorrhagic and can kill quickly due to severe necrosis in the intestine and bleeding.