L.7 Liver Flashcards
What are the two sources of blood supply to the liver?
Portal vein & hepatic artery
The liver has a dual blood supply which is crucial for its function.
What shape are the lobules of the liver?
Pentagonal / hexagonal
The unique shape of liver lobules is important for its structural organization.
What is the functional unit of the liver?
Liver acinus
The liver acinus is essential for the metabolic activities of the liver.
What structure runs between the portal triad and the central vein in the liver?
Portal tract
The portal tract connects key components within the liver lobule.
What type of cells line the liver sinusoids?
Hepatocytes
Hepatocytes are responsible for the metabolic functions of the liver.
How does blood enter and exit the acinus in the liver?
Enters via the portal tract and exits via the central vein
This flow is crucial for liver function and blood filtration.
List the four main functions of the liver.
- Synthesis
- Storage
- Metabolism
- Detoxification/excretion
These functions are vital for maintaining homeostasis.
What is glycogenesis?
Conversion of glucose to glycogen
Glycogenesis is a key process for energy storage in the liver.
What is glycogenolysis?
Conversion of glycogen to glucose
This process is essential for releasing glucose into the bloodstream.
What is gluconeogenesis?
Conversion of amino acids to glucose
Gluconeogenesis helps maintain blood glucose levels during fasting.
What are the primary lipid synthesis processes in the liver?
- Cholesterol metabolism
- Lipoprotein synthesis
- Fatty acid synthesis
- Ketogenesis
These processes are crucial for lipid homeostasis and energy production.
What is ketogenesis?
Conversion of acetyl CoA to ketone bodies
Ketogenesis is important during periods of low carbohydrate intake.
What proteins does the liver synthesize?
Most plasma proteins
Plasma proteins are critical for various physiological functions, including blood clotting.
What is the role of the liver in vitamin D synthesis?
Synthesis of vitamin D
The liver plays a vital role in converting vitamin D into its active form.
What components are involved in bile formation?
- Cholesterol
- Bilirubin
- Bile salts
Bile is essential for the digestion and absorption of fats.
What is glycogen?
A stored form of glucose in the liver and muscles
Glycogen serves as a quick source of energy during physical activity.
What are triglycerides?
A type of fat found in the body, used for energy storage
Triglycerides are composed of glycerol and three fatty acids.
Name the fat-soluble vitamins.
- A
- D
- E
- K
These vitamins are stored in the body’s fatty tissue.
Name the water-soluble vitamins.
- B12
- folic acid
Water-soluble vitamins must be consumed more frequently as they are not stored in the body.
Which minerals are mentioned?
- iron (ferritin)
- copper
- zinc
These minerals play various roles in bodily functions, including enzyme activity and oxygen transport.
What is glycolysis?
The process of converting glucose to pyruvate
Glycolysis is the first step in cellular respiration.
What does glycogenolysis refer to?
The breakdown of glycogen to glucose
This process occurs during fasting or intense exercise.
Define gluconeogenesis.
The formation of glucose from amino acids
This process is crucial during prolonged fasting.
What is beta-oxidation?
The conversion of fatty acids to acetyl-CoA
This process is essential for fat metabolism.
What is ketogenesis?
The production of ketone bodies from acetyl-CoA
Ketogenesis occurs during low carbohydrate intake or fasting.
What is glycogenesis?
The process of converting glucose to glycogen
This process is vital for energy storage.
Define lipogenesis.
The conversion of glucose to fat
Lipogenesis occurs when there is excess glucose in the body.
What is first pass metabolism?
The process where substances absorbed from the gut pass through the liver before systemic circulation
This process helps detoxify and metabolize drugs.
What is second pass metabolism?
The metabolism of ammonia, bilirubin, drugs, alcohol, and toxins in the liver
This process further detoxifies substances after first pass metabolism.
What role does the liver play in hormone metabolism?
Deactivation of hormones such as insulin, glucagon, thyroid hormones, cortisol, and catecholamines
This ensures hormonal balance and proper physiological responses.
What are Kuppfer cells?
Specialized macrophages in the liver that perform phagocytosis of bacteria, viruses, and foreign particles
They play a critical role in the immune response.
What is ammonia’s effect on the central nervous system?
Toxic to the central nervous system (CNS)
What barrier does ammonia freely cross?
Blood-brain barrier
What process converts ammonia to urea?
Urea cycle
How does urea compare to ammonia in terms of toxicity?
Less toxic than ammonia
What is a key characteristic of urea in terms of solubility?
Water soluble (excreted in urine)
What components make up bile?
- Bilirubin
- Cholesterol
- Bile salts
- Phospholipids
- Water
- Electrolytes
How much bilirubin do we produce daily?
300-400 mg
What is the healthy liver capacity for bilirubin production?
X10 this amount
What are the two forms of bilirubin?
- Unconjugated (indirect) bilirubin (lipid soluble)
- Conjugated (direct) bilirubin (water soluble)
Is bilirubin excreted in urine?
No, it is not excreted in the urine
What is the solubility of unconjugated bilirubin in water?
Poorly soluble in water
What is the state of bilirubin in the blood?
Protein bound in the blood
What does bilirubinuria indicate?
↑ conjugated bilirubin
