Liver
• Hepatocytes are polyhedral in shape with round nuclei. Sinusoids lined by endothelial cells. Also contains phagocytic macrophages called Kupffer cells.
• The flow of blood is from portal triad towards the central vein whereas the flow of bile is towards the periphery of the lobules.
• Portal acinus-the area between two adjacent central veins with the central axis formed by the branch of hepatic artery and portal vein.
• Connective tissue capsule sends septa inside and divide the parenchyma into lobules.
• Classical liver lobule is hexagonal in shape.
• At the center it contains a central vein with branching and anastomosing plates of hepatocytes radiating outwards. These plates of hepatocytes are separated by simustik
• At the periphery of the tobule portal triads are present which contain branches of hepatic artery and portal vein with bile ductulee
• Portal lobule-hexagonal lobule with portal triad at the center and central veins at the periphery.
Gall Bladder
• There are extensive mucosal fold into the lumen which allows the distension of bladder and increase the surface area for absorption (concentration of bille)
• Gallbladder is a three layered structure.
1. Mucosal layer-lined by simple tall columnar epithelium lying over a layer of lamina propria. Columnar cells have apical microvilli which help in absorption.
2. Fibromuscular layer-made of connective tissue and smooth muscles fibers.
3. Outer layer of serosa-peritoneal covering made of flat squamous cells. Areas not covered with the serous membrane contain only loose connective tissue called adventitia.