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L.7 Liver Flashcards

1
Q

What are the two sources of blood supply to the liver?

A

Portal vein & hepatic artery

The liver has a dual blood supply which is crucial for its function.

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2
Q

What shape are the lobules of the liver?

A

Pentagonal / hexagonal

The unique shape of liver lobules is important for its structural organization.

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3
Q

What is the functional unit of the liver?

A

Liver acinus

The liver acinus is essential for the metabolic activities of the liver.

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4
Q

What structure runs between the portal triad and the central vein in the liver?

A

Portal tract

The portal tract connects key components within the liver lobule.

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5
Q

What type of cells line the liver sinusoids?

A

Hepatocytes

Hepatocytes are responsible for the metabolic functions of the liver.

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6
Q

How does blood enter and exit the acinus in the liver?

A

Enters via the portal tract and exits via the central vein

This flow is crucial for liver function and blood filtration.

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7
Q

List the four main functions of the liver.

A
  • Synthesis
  • Storage
  • Metabolism
  • Detoxification/excretion

These functions are vital for maintaining homeostasis.

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8
Q

What is glycogenesis?

A

Conversion of glucose to glycogen

Glycogenesis is a key process for energy storage in the liver.

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9
Q

What is glycogenolysis?

A

Conversion of glycogen to glucose

This process is essential for releasing glucose into the bloodstream.

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10
Q

What is gluconeogenesis?

A

Conversion of amino acids to glucose

Gluconeogenesis helps maintain blood glucose levels during fasting.

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11
Q

What are the primary lipid synthesis processes in the liver?

A
  • Cholesterol metabolism
  • Lipoprotein synthesis
  • Fatty acid synthesis
  • Ketogenesis

These processes are crucial for lipid homeostasis and energy production.

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12
Q

What is ketogenesis?

A

Conversion of acetyl CoA to ketone bodies

Ketogenesis is important during periods of low carbohydrate intake.

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13
Q

What proteins does the liver synthesize?

A

Most plasma proteins

Plasma proteins are critical for various physiological functions, including blood clotting.

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14
Q

What is the role of the liver in vitamin D synthesis?

A

Synthesis of vitamin D

The liver plays a vital role in converting vitamin D into its active form.

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15
Q

What components are involved in bile formation?

A
  • Cholesterol
  • Bilirubin
  • Bile salts

Bile is essential for the digestion and absorption of fats.

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16
Q

What is glycogen?

A

A stored form of glucose in the liver and muscles

Glycogen serves as a quick source of energy during physical activity.

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17
Q

What are triglycerides?

A

A type of fat found in the body, used for energy storage

Triglycerides are composed of glycerol and three fatty acids.

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18
Q

Name the fat-soluble vitamins.

A
  • A
  • D
  • E
  • K

These vitamins are stored in the body’s fatty tissue.

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19
Q

Name the water-soluble vitamins.

A
  • B12
  • folic acid

Water-soluble vitamins must be consumed more frequently as they are not stored in the body.

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20
Q

Which minerals are mentioned?

A
  • iron (ferritin)
  • copper
  • zinc

These minerals play various roles in bodily functions, including enzyme activity and oxygen transport.

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21
Q

What is glycolysis?

A

The process of converting glucose to pyruvate

Glycolysis is the first step in cellular respiration.

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22
Q

What does glycogenolysis refer to?

A

The breakdown of glycogen to glucose

This process occurs during fasting or intense exercise.

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23
Q

Define gluconeogenesis.

A

The formation of glucose from amino acids

This process is crucial during prolonged fasting.

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24
Q

What is beta-oxidation?

A

The conversion of fatty acids to acetyl-CoA

This process is essential for fat metabolism.

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25
What is ketogenesis?
The production of ketone bodies from acetyl-CoA ## Footnote Ketogenesis occurs during low carbohydrate intake or fasting.
26
What is glycogenesis?
The process of converting glucose to glycogen ## Footnote This process is vital for energy storage.
27
Define lipogenesis.
The conversion of glucose to fat ## Footnote Lipogenesis occurs when there is excess glucose in the body.
28
What is first pass metabolism?
The process where substances absorbed from the gut pass through the liver before systemic circulation ## Footnote This process helps detoxify and metabolize drugs.
29
What is second pass metabolism?
The metabolism of ammonia, bilirubin, drugs, alcohol, and toxins in the liver ## Footnote This process further detoxifies substances after first pass metabolism.
30
What role does the liver play in hormone metabolism?
Deactivation of hormones such as insulin, glucagon, thyroid hormones, cortisol, and catecholamines ## Footnote This ensures hormonal balance and proper physiological responses.
31
What are Kuppfer cells?
Specialized macrophages in the liver that perform phagocytosis of bacteria, viruses, and foreign particles ## Footnote They play a critical role in the immune response.
32
What is ammonia's effect on the central nervous system?
Toxic to the central nervous system (CNS)
33
What barrier does ammonia freely cross?
Blood-brain barrier
34
What process converts ammonia to urea?
Urea cycle
35
How does urea compare to ammonia in terms of toxicity?
Less toxic than ammonia
36
What is a key characteristic of urea in terms of solubility?
Water soluble (excreted in urine)
37
What components make up bile?
* Bilirubin * Cholesterol * Bile salts * Phospholipids * Water * Electrolytes
38
How much bilirubin do we produce daily?
300-400 mg
39
What is the healthy liver capacity for bilirubin production?
X10 this amount
40
What are the two forms of bilirubin?
* Unconjugated (indirect) bilirubin (lipid soluble) * Conjugated (direct) bilirubin (water soluble)
41
Is bilirubin excreted in urine?
No, it is not excreted in the urine
42
What is the solubility of unconjugated bilirubin in water?
Poorly soluble in water
43
What is the state of bilirubin in the blood?
Protein bound in the blood
44
What does bilirubinuria indicate?
↑ conjugated bilirubin
45
What is jaundice?
Yellowing of the skin and eyes due to bilirubin accumulation. ## Footnote Jaundice indicates elevated bilirubin levels in the body.
46
What can cause elevated bilirubin levels?
Elevated bilirubin levels can be due to: * Increased production * Hepatocellular damage * Biliary obstruction / cholestasis ## Footnote Understanding these causes is essential for diagnosing liver and biliary tract conditions.
47
How can conjugated vs unconjugated bilirubin levels help in diagnosis?
They can help to differentiate the cause of jaundice. ## Footnote Analyzing the types of bilirubin can indicate whether the issue is hepatic or pre-hepatic.
48
What is the total bilirubin reference range?
<20.0μmol/L ## Footnote Total bilirubin includes both conjugated and unconjugated bilirubin.
49
What is the direct bilirubin reference range?
<5.1μmol/L ## Footnote Direct bilirubin refers to conjugated bilirubin, which is water-soluble.
50
What is the indirect bilirubin reference range?
<12.0μmol/L ## Footnote Indirect bilirubin refers to unconjugated bilirubin, which is not water-soluble.
51
How does bilirubin react in the measurement process?
Bilirubin reacts with diazotized sulfanilic acid in an acidic medium to form a blue azopigment. ## Footnote This reaction is part of the laboratory testing for bilirubin levels.
52
What role does a catalyst like caffeine play in bilirubin measurement?
It causes a shift in wavelength of maximum absorbance. ## Footnote This shift is important for accurately measuring bilirubin levels.
53
Why is it necessary to make unconjugated bilirubin water soluble?
To measure total bilirubin (conjugated + unconjugated). ## Footnote This allows for a comprehensive assessment of bilirubin levels in the body.
54
What are the applications of liver function tests?
Applications include: * Screening for liver disease * Diagnosing liver disease * Prognosis of liver disease * Monitoring progression of liver disease ## Footnote Liver function tests are essential in assessing liver health.
55
Why is liver function testing considered a misnomer?
Very few tests actually measure liver function ## Footnote The term 'liver function tests' can be misleading.
56
What must occur before liver function tests show abnormal results?
Liver damage must be severe ## Footnote This highlights the limitations of liver function tests.
57
What do functional assays measure in liver function tests?
They measure clearance of metabolic products and synthesis of proteins ## Footnote These assays provide insights into liver activity.
58
What factors influence the variability of liver function tests?
Time consumption, hepatic blood flow, and huge variability ## Footnote These factors can complicate the interpretation of results.
59
What are the primary functions of liver function tests?
They reflect liver status and help differentiate: * Acute hepatocellular damage * Cholestasis * Chronic liver disease ## Footnote LFTs are crucial for understanding liver health.
60
What enzymes are commonly included in liver function tests?
Common enzymes include: * ALP (alkaline phosphatase) * ALT (alanine aminotransferase) * AST (aspartate aminotransferase) * GGT (gamma-glutamyl transferase) ## Footnote These enzymes provide insight into liver function and damage.
61
What are aminotransferases and their role in liver function tests?
Aminotransferases (ALT/AST) produce non-essential amino acids through transamination ## Footnote They are sensitive indicators of hepatocellular damage.
62
What is a key characteristic of ALT and AST in the context of liver damage?
They are sensitive indicators of hepatocellular damage but not specific to liver damage ## Footnote ALT and AST can also be elevated due to issues in muscle, heart, or kidney.
63
What principle underlies the measurement of ALT and AST?
Enzymes catalyze the reversible transamination of L-alanine (ALT) or L-aspartate (AST) and α-ketoglutarate to pyruvate/oxaloacetate and L-glutamate ## Footnote This biochemical process is central to understanding liver function tests.
64
What is measured at 340nm in the context of ALT and AST tests?
NADH reduction is measured ## Footnote This measurement is crucial for determining enzyme activity.
65
What is Alkaline Phosphatase (ALP)?
Group of enzymes that hydrolyze phosphate esters ## Footnote ALP is expressed widely in the body, including the liver, bone, kidney, placenta, and intestine.
66
Where is the liver isoform of Alkaline Phosphatase located?
On the outside of the bile canalicular membrane of hepatocytes ## Footnote This location is crucial for its function in bile secretion.
67
In which condition is Alkaline Phosphatase elevated?
Cholestasis (obstruction of bile flow) ## Footnote Elevated ALP can indicate liver dysfunction or bile flow obstruction.
68
How do age-dependent reference ranges for Alkaline Phosphatase vary?
* Elevated in children and adolescents (bone growth) * Decreased in elderly (bone resorption) ## Footnote These variations reflect different physiological states in bone metabolism.
69
What substrate does Alkaline Phosphatase break down in alkaline conditions?
p-nitrophenyl phosphate ## Footnote This reaction produces p-nitrophenol, which is a yellow product indicative of enzyme activity.
70
What is Gamma-Glutamyl Transferase (GGT)?
Enzyme which transfers the γ-glutamyl group from γ-glutamyl peptides to amino acids ## Footnote GGT is involved in amino acid metabolism and is an important marker in liver function tests.
71
Where is Gamma-Glutamyl Transferase located?
On the external surface of the cell membrane ## Footnote GGT is found in the liver, kidney, pancreas, and intestine.
72
In which conditions can Gamma-Glutamyl Transferase be elevated?
* All forms of liver disease * Cholestasis * Alcohol-induced liver disease ## Footnote GGT levels can help differentiate between types of liver dysfunction.
73
What is the principle of the GGT test?
GGT catalyzes the transfer of a gamma-glutamyl group from gamma-glutamyl-p-nitroaniline to glycylglycine, producing nitroaniline or nitrobenzoate ## Footnote The yellow product is measured at 405nm, indicating enzyme activity.

Clinical Chemistry (21 decks)

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