The Liver and Gall Bladder

The Liver and Gall Bladder

The Liver

• The heaviest gland of the body, weighing about 1.4 kg

• Second largest organ

• Inferior to the diaphragm

• occupies most of the right hypochondriac and part of the epigastric regions of the abdomino pelvic cavity

Anatomy of Liver

• Almost completely covered by visceral peritoneum

• Covered by a dense irregular connective tissue layer that lies deep to the peritoneum

• The liver is divided into two principal lobes

The Gallbladder

• Pear-shaped sac

• Located in a depression of the posterior surface of the liver

• Typically hangs from the anterior inferior margin of the liver

Anatomy of Gallbladder

The parts of the gallbladder:

• The broad fundus - Projects inferiorly beyond inferior border of liver

• The body - Central portion

• The neck - Tapered portion

• The body and neck project superiorly

Histology of Liver

• The lobes are made up of lobules

Lobules contain:

• Hepatocytes (liver cells)

• Sinusoids

• Stellate reticulo endothelial (Kupffer) cells

• Central vein

Hepatic blood flow


• Major functional cells of the liver

• Perform a wide array of metabolic & endocrine functions

• Specialized epithelial cells with 5 to 12 sides

• Make up about 80% of the volume of the liver

The Hepatic Laminae

• Plates of hepatocytes

• Thick bordered by hepatic sinusoids

• Highly branched, irregular structures

• Bile

– A yellow, brownish, or olive-green liquid

– Secreted by hepatocytes

– Serves as both an excretory product and a digestive secretion

• Bile canaliculi

– Small ducts between hepatocytes

– Collect bile produced by the hepatocytes

– From bile canaliculi, bile passes into bile ductules & then bile ducts

Hepatic Ducts

Hepatic Sinusoids

• Highly permeable blood capillaries between rows of hepatocytes

• Receive oxygenated blood from branches of the hepatic artery

• Nutrient-rich deoxygenated blood from branches of the hepatic portal vein

• Converge and deliver blood into a central vein

• From central veins, the blood flows into the hepatic veins, which drain into the inferior vena cava

Portal Triad

• Together, a bile duct, branch of the hepatic artery, and branch of the hepatic vein

• Anatomical and functional units

Functions of Liver

• Carbohydrate metabolism

– Maintaining a normal blood glucose level

– Convert certain amino acids and lactic acid to glucose

– Liver converts glucose to glycogen and triglycerides for storage

• Lipid metabolism

– Store some triglycerides

– Break down fatty acids to generate ATP

– Synthesize lipoproteins (Which transport FA, TG and cholesterol)

– Synthesize cholesterol and use cholesterol to make bile salts

• Protein metabolism

– Hepatocytes deaminate amino acids used for ATP production or converted to carbohydrates or fats

– The resulting toxic ammonia converted into the much less toxic urea, which is excreted in urine

– Synthesize most plasma proteins, such as alpha and beta globulins, albumin, prothrombin and fibrinogen

• Phagocytosis

– Kupffer cells of the liver phagocytize aged RBC, WBC & bacteria

• Processing of drugs and hormones

– Detoxify substances such as alcohol

– Excrete drugs such as penicillin, erythromycin, and sulfonamides into bile

– Chemically alter or excrete thyroid hormones and steroid hormones

• Storage

– Prime storage site for certain vitamins (A, D, E, K and B12) and minerals (iron and copper)

– Released from the liver when needed elsewhere in the body

• Excretion of bilirubin

– Bilirubin, derived from the heme of aged RBC, absorbed by the liver from the blood and secreted into bile

– Most of the bilirubin in bile is metabolized in the small intestine by bacteria and eliminated in feces

• Synthesis of bile salts

– Bile salts are used in the small intestine for the emulsification and absorption of lipids

• Activation of vitamin D

– The skin, liver, and kidneys participate in synthesizing the active form of vitamin D

Functions of Gallbladder

– Store and concentrate the bile produced by the liver (up to tenfold) until it is needed in the small intestine

– In the concentration process, water and ions are absorbed by the gallbladder mucosa

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