gall bladder

Question 1

what is the function of the gall bladder?

Answer 1

store and concentrate bile

Question 2

what are the main components of bile?

Answer 2

• Bile salts
• lecithin
• cholesterol
• bile pigments (bilirubin)

Question 3

what stimulates gall bladder contractions? where is it secreted?

Answer 3

CCK

secreted from the duodenun

Question 4

CCK stimulates gall bladder contraction, what other effects does it have?

Answer 4

• stimulates more bile to be produced from hepatocytes
• the contraction of the sphincter of oddi
• pancreatic acinar stimulation
• inhibition of gastric emptying

Question 5

what is the function of bile?

Answer 5

to emulsify fat in the duodenum

Question 6

how is bile stored in the gall bladder? why?

Answer 6

molecules are agrregated together so the emulsifying effect doesn’t damage the mucosal membranes.

Question 7

describe a bile caniculi.

Answer 7

• not true vessels
• spaces between cells generated by tight junctions and desmosomes
• don’t have specialised walls they’re more like grooves between cells
• They have specialised pumps in the walls to pump bile content into the caniculi

Question 8

what is bilirubin?

Answer 8

a toxic molecule that is made from the breakdown of haem groups due to RBC breakdown

Question 9

how does unconjugated bilirubin travel around the blood?

Answer 9

attached to albumin

Question 10

where does bilirubin conjugation take place? what is the enzyme that catalyses the reaction called?

Answer 10

In hepatocytes by UDP-glucuronyl transferase

Question 11

what happens to bilirubin after excreted in bile?

Answer 11

-enters the intestines
-reduced by gut bacteria to urobilinogen
after this it’s either
-oxidised in the gut to form stercobilin which is excreted in faeces giving it it’s brown colour
-reabsorbed by the intestines and secreted in the urine as urobilin giving urine it’s yellow colour

Question 12

what happens during conjugation of bilirubin?

Answer 12

the addition of a glucuronic acid

Question 13

What is jaundice?

Answer 13

a yellow discolouration of the skin and sclerae as a result of raised serum bilirubin

Question 14

what are the three types of jaundice?

Answer 14

• pre-hepatic
• hepatic
• post-hepatic

Question 15

what is pre-hepatic jaundice? what are some causes?

Answer 15

an increased break down in RBC leading to increased unconjugated bilirubin in the blood

causes - malaria, sickle cell, normal in new borns

Question 16

what is post-hepatic jaundice? what are some causes?

Answer 16

occurs when the biliary system is blocked, damaged or inflamed.

causes - gall stones, pancreatic cancer, gall bladder cancer, pancreatitis