Liver Functions

Summary

Dr. Mike's video explores the liver's multifaceted roles, including its structure, blood filtration and storage, metabolism, detoxification, bile production, and regenerative capabilities. It delves into the liver's vital functions such as nutrient processing, detoxification of harmful substances, and the synthesis of essential proteins and vitamins. The video also highlights the liver's impressive ability to regenerate, emphasizing its critical importance to overall health.

Takeaways

• 📐 The liver is the largest internal organ, weighing about 1.5 kilograms and located in the upper right quadrant of the abdomen.
• 🔍 It functions through small hexagonal structures called lobules, of which there are 50,000 to 100,000 per liver, facilitating its many roles.
• 🌀 The liver's primary functions can be categorized into filtration and storage of blood, metabolism and detoxification, bile formation, and regeneration.
• 🩸 It filters blood through the portal vein and hepatic artery, receiving about 1300 mls of blood and playing a crucial role in immune response with Kupffer cells.
• 💧 The liver stores approximately 10% of the body's circulating blood, which can increase to over a liter in cases of heart failure or valve issues.
• 🍽️ Metabolism involves processing nutrients from proteins, fats, and carbohydrates, and regulating nutrient levels in other tissues.
• 🔄 The liver is central to glucose regulation, storing it as glycogen and releasing it through glycogenolysis or gluconeogenesis.
• 🧘‍♂️ Protein metabolism in the liver includes the synthesis of important proteins like albumin, coagulation factors, and protease inhibitors.
• 🚫 Detoxification involves the liver's role in handling potentially toxic substances through xenobiotic metabolism with phase one and two processes.
• 🟡 Bile production by the liver is essential for emulsifying fats and aiding in the absorption of fat-soluble vitamins (A, D, E, K).
• ♻️ The liver has a remarkable ability to regenerate, capable of regrowing up to 70% of its mass in a short period after significant loss.

Q & A

What is the liver's location and average weight in the human body?

The liver is located in the upper right quadrant of the abdomen and it weighs around 1.5 kilograms on average.

What percentage of body weight does the liver constitute and why is it significant?

The liver constitutes about 2 percent of body weight, making it significant as it is the largest internal organ in the body.

What are liver lobules and what is their role?

Liver lobules are hexagonal-shaped functional subunits within the liver that perform all the liver's work. They are responsible for the liver's many functions despite their small size, ranging from 0.8 to 2 millimeters in diameter.

How many liver lobules are there in a single liver?

There are between 50,000 to 100,000 liver lobules in a single liver.

What are the four main categories of liver functions mentioned in the script?

The four main categories of liver functions are filtration and storage of blood, metabolism and detoxification, bile formation, and regeneration.

How much blood does the liver receive and from which vessels?

The liver receives about 1300 mls of blood from two main vessels: the portal vein, which carries blood from the gastrointestinal tract, and the hepatic artery, which supplies oxygenated blood.

What is the role of Kupffer cells in the liver?

Kupffer cells, located in the sinusoids of the liver, play a crucial role in engulfing bacteria and other invading pathogens, thus contributing to the liver's filtration process.

How does the liver store blood and what is its significance?

The liver can store approximately 450 mls of blood, which is about 10 percent of the body's circulating blood volume. This storage capacity is significant as it can expand in cases of heart failure or other conditions, serving as an important blood reservoir.

What is the liver's role in metabolism and detoxification?

The liver plays a vital role in the uptake, processing, and distribution of nutrients such as proteins, fats, and carbohydrates. It also detoxifies potentially harmful substances through xenobiotic metabolism, which involves two phases of detoxification.

How does the liver handle the metabolism of red blood cells?

The liver metabolizes red blood cells by breaking down hemoglobin into biliverdin and then into unconjugated bilirubin. This bilirubin is then conjugated in the liver and can be excreted through the kidneys or intestines.

What is the significance of bile in digestion and absorption of vitamins?

Bile, produced by the liver, emulsifies fats in the small intestine, making them more accessible for enzymatic breakdown. It is also crucial for the absorption of fat-soluble vitamins A, D, E, and K.

How does the liver regenerate itself after damage?

The liver has a remarkable capacity for regeneration. For example, in mice, up to 70 percent of the liver can regenerate in just seven days, highlighting its importance and evolutionary adaptation to self-repair.