Laboratory Investigation of Liver and GI tract Flashcards Preview

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Flashcards in Laboratory Investigation of Liver and GI tract Deck (163)
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1

Where is the liver located?

➝ upper right quadrant of the abdomen

2

How much does the liver weigh?

➝ 22g/kg of body weight

3

What kind of a blood supply does the liver have?

➝ dual blood supply
➝ 2/3 comes from the gut via the portal vein
➝ 1/3 comes from hepatic artery

4

How does blood leave the liver?

➝ Through the hepatic veins

5

How many lobes are there in the liver?

➝ 2

6

What do the lobes consist of?

➝ multiple liver lobules

7

What do the lobules consist of?

➝ sheets of hepatocytes radiating from a central vein which carries blood from the liver

8

What can each lobule be further divided into?

➝ liver acini

9

What are liver acini?

➝ the smallest functional unit of the liver

10

How are substances for excretion excreted?

➝ secreted from hepatocytes into canaliculi

11

How does the hepatic duct form?

➝ bile canaliculi merge and form bile ductules which subsequently merge to become a bile duct and eventually become the common hepatic duct

12

What are the 8 functions of the liver?

➝Carbohydrate metabolism
➝Fat metabolism
➝Protein metabolism
➝Synthesis of plasma proteins
➝Hormone metabolism
➝Metabolism and excretion of drugs and foreign compounds
➝Storage - glycogen, vitamin A and B12 plus iron and copper
➝Metabolism and excretion of bilirubin

13

What are 4 common disease processes affecting the liver?

➝ Hepatitis
➝ Cholestasis
➝ Cirrhosis
➝ Tumors

14

What is hepatitis and what can it lead to?

➝ Damage to hepatocytes
➝Leads to fibrosis and blocks the canals

15

What is cholestasis?

➝ blockage
➝ intra or extrahepatic

16

What does cirrhosis lead to?

➝ Increased fibrosis
➝Liver shrinkage
➝Decreased hepatocellular function
➝Obstruction of bile flow

17

What are liver function tests sensitive and insensitive to?

➝ Insensitive indicators of liver function
➝ Sensitive indicators of liver damage

18

What must interpretation of biochemical tests be done with?

➝ Interpretation must be performed within the context of the patient’s risk factors, symptoms, medications, current condition/illness and physical findings

19

What are the 5 things measured in a standard LFT profile?

➝Bilirubin
➝Albumin
➝Alanine aminotransferase (ALT) or aspartate aminotransferase (AST)
➝Alkaline phosphatase
➝Gamma glutamyltransferase

20

What are the 6 things that LFTs can be used for?

➝ Screening for the presence of liver disease
➝ assessing prognosis
➝ measuring the efficacy of treatments for liver disease
➝ differential diagnosis : predominantly hepatic or cholestatic
➝ monitoring disease progression
➝ assessing severity, especially in patients with cirrhosis

21

What are the LFTs for a cholestatic pattern?

➝ Bilirubin high to very high
➝ ALT normal to high
➝ ALP high to very high
➝ Albumin normal

22

What are the LFTs for an inflammatory pattern?

➝ Bilirubin normal to high
➝ ALT very high
➝ ALP normal to high
➝ Albumin normal

23

What is ALT released from?

➝ damaged cells

24

When do albumin concentrations decrease?

➝ in chronic liver disease

25

What is bilirubin?

➝Yellow orange pigment derived from haem

26

What are the two forms of bilirubin?

➝ Conjugated (direct reacting bilirubin)
➝Unconjugated (indirect reacting bilirubin)

27

Which form of bilirubin is hydrophobic?

➝Unconjugated

28

What is the reference range for total bilirubin?

➝ <21 umol/L

29

What is the reference range for conjugated bilirubin?

➝ <10umol/L

30

What does bilirubin bind to?

➝ tightly but reversibly to albumin