Скачать или смотреть Liver Anatomy Explained: Lobes, Blood Supply & Bile Flow

00:00 - Introduction
00:17 - Lobes
01:35 - Capsule
02:47 - Blood Vessels
05:04 - Bile Ducts
06:51 - Gallbladder
09:40 - Conclusion

The liver is the largest internal organ, situated in the upper right quadrant of the abdomen beneath the diaphragm. It extends from the right side to the midline and has a triangular yet irregular shape due to its lobes and segments.

Lobes
Right Lobe: The largest and most prominent lobe, located on the right side. It is divided into anterior and posterior segments by the right hepatic vein.

Left Lobe: Smaller, found on the left side, and divided into medial and lateral segments.

Quadrate Lobe: A small, square-shaped lobe beneath the liver near the gallbladder.

Caudate Lobe: A tail-like extension on the liver’s posterior surface near the vena cava.

These distinct lobes contribute to the liver’s complex, wedge-shaped structure.

Capsule
The liver capsule is a dense, fibrous tissue made of collagen, surrounding the liver for protection and structural support. It anchors the liver to surrounding organs and maintains its position. The capsule is rich in nerve fibers, making it sensitive to pressure and stretch, useful in diagnosing liver conditions via physical exams.

Blood Vessels
The liver is highly vascular, supported by an intricate network of blood vessels:

Hepatic Artery: Supplies oxygen-rich blood, crucial for liver metabolism.

Portal Vein: Carries nutrient-rich, oxygen-poor blood from the digestive tract to the liver for processing.

Hepatic Portal System: Filters and detoxifies substances before they enter systemic circulation.

Hepatic Veins: Drain deoxygenated blood from the liver into the inferior vena cava.

Sinusoids: Microscopic vessels within the liver where nutrient and gas exchange occurs, lined by hepatocytes.

Bile Ducts
Bile ducts form a network of tubular structures transporting bile:

Intrahepatic Ducts: Collect bile from hepatocytes within the liver.

Extrahepatic Ducts: Include left and right hepatic ducts, merging into the common hepatic duct.

Common Bile Duct: Formed by the union of the common hepatic duct and cystic duct, delivering bile to the small intestine.

Sphincters: The hepatopancreatic sphincter and sphincter of the duodenal papilla control bile release into the duodenum.

This system allows bile delivery for fat digestion, regulated by muscular valves.

Gallbladder
The gallbladder is a small, pear-shaped, muscular organ located beneath the liver. It stores and concentrates bile produced by the liver. Measuring around 7–10 cm, it consists of a neck, body, and fundus.

Function: Stores bile and releases it upon fat consumption to help emulsify fats for digestion.

Bile Production & Storage: The liver constantly produces bile, which the gallbladder stores and concentrates by removing water and electrolytes.

Bile Composition: Contains water, bile salts, bilirubin, cholesterol, and electrolytes. Bile salts aid in digestion; bilirubin gives bile its color.

Regulation: The hormone cholecystokinin (CCK) triggers gallbladder contraction and sphincter relaxation, enabling bile flow into the duodenum.

Gallstones and Removal
Gallstones: Form from cholesterol or bilirubin, potentially blocking bile flow and causing cholecystitis, choledocholithiasis, or infections.

Removal (Cholecystectomy): Surgical removal is common and generally does not hinder digestion, as the liver continues bile production directly to the intestine.

The liver is a vital organ, central to metabolism, detoxification, digestion, and immune function. Its complex structure and multifaceted roles make it indispensable for sustaining human health.