Liver Functions and Metabolism Quiz

Liver Functions

• The liver plays a crucial role in maintaining overall health and life by performing a broad range of functions.
• Maintaining nutrient homeostasis: The liver regulates blood nutrient levels. This includes glucose supply for neurons, and distributing fatty acids as ketones or triglycerides (VLDLs).
• Storing nutrients: Glycogen is stored in the liver to release glucose during times of need, and the liver stores lipids as well.
• Synthesizing and releasing plasma proteins: The liver creates many plasma proteins, including clotting factors and albumin.
• Synthesizing and releasing bile: Bile, containing bile salts and other components, helps digest fats.
• Processing and excreting bilirubin: The liver processes and eliminates bilirubin, a waste product.
• Detoxification and excretion: The liver removes toxins, drugs, and hormones, and prepares them for excretion.
• Storing vitamins: The liver stores vitamins A, D, and B12 for a period of time, preventing deficiencies.
• Iron storage: The liver stores iron in the form of ferritin, ensuring its availability for red blood cell production.
• Synthesizing somatomedins: The liver plays a crucial role in producing hormones related to growth.
• Blood cleansing: The liver filters blood, removing bacteria and other potential threats.

Carbohydrates

• Carbohydrate storage: The liver stores glucose as glycogen.
• Glycogenolysis: This is the breakdown of glycogen to release glucose when needed.
• Gluconeogenesis: The liver creates glucose from non-carbohydrate sources.
• Dietary sugar processing: The liver processes galactose and fructose from the diet.

Lipids

• Lipid synthesis and release: The liver synthesizes and releases VLDLs (very-low-density lipoproteins), and HDLs (high-density lipoproteins).
• Ketone production: The liver creates ketones from fatty acids.
• Lipid Storage: The liver stores lipids as triglycerides but this is more prevalent in disease conditions.

Amino Acids

• Amino acid handling and glucose production: The liver processes amino acids from skeletal muscle protein breakdown, primarily creating glucose via gluconeogenesis.
• Non-essential amino acid synthesis: The liver plays a pivotal role in synthesizing many non-essential amino acids, rather than consuming them externally.
• Urea production: The liver plays a crucial role in removing nitrogenous groups from amino acids, producing urea (a major waste product).

Nutrient Storage

• Glycogen storage: The liver efficiently stores glycogen, ready for release during low glucose periods.
• Lipid storage: While not a primary function, the liver can store lipids, particularly triglycerides. This storage is more common in disease states.

Plasma protein synthesis

• Clotting factors: The liver produces several essential clotting factors, needing vitamin K for some.
• Albumin: Albumin, is the most abundant plasma protein, maintaining osmotic balance and binding various substances.

Bile synthesis and function

• Bile Composition: Bile contains bile salts, which emulsify fats, and components like cholesterol and bilirubin.
• Fat Emulsification: Bile salts break down large fat globules into smaller ones, aiding in digestion and absorption.

Detoxification

• Drug and hormone metabolism: The liver processes drugs and hormones, making them more excretable, or changing their activity.
• Phase I and II reactions: The liver uses biotransformations to make drugs and hormones more water-soluble for excretion.

Other Functions

• Vitamin storage: The liver significantly stores vitamins A, D, and B12.
• Iron storage: The liver stores iron as ferritin, making it available for red blood cell production.
• Somatomedin synthesis: The liver produces hormones that stimulate growth.
• Blood purification: The Kupffer cells within the liver remove bacteria and other foreign material from the bloodstream.