Structure and functions of liver

Structure and functions of Liver

1. Human Anatomy and Physiology-II Digestive system (Liver) Mr N.JEGAN Associate Professor K.M.COLLEGE OF PHARMACY. MADURAI.

2. Structure of Liver

3. Liver- Location It is located in the upper and right side of the abdominal cavity immediately beneath diaphragm and above the stomach  .

4. Liver -structure Liver is the largest gland in human body Weight- 1500 grams ( 2.5% of the total body weight) Colour -   Reddish-brown Shape - Wedge

5. Liver-Lobes( Hepatic Lobes) The liver has four lobes . From Anterior view 1.Right lobe (Large) 2.Left lobe(Small) From Posterior view 3.Caudate lobe 4.Quadrate lobe

6. Liver-Lobules(Hepatic Lobules) Hepatic lobule is the structural and functional unit of liver . There are about 50,000 to 100,000 lobules in the liver . The lobule is a honeycomb-like structure and it is made up of liver cells called hepatocytes (Liver cell).

7. Hepatocytes and Hepatic Plates Hepatocytes are arranged in columns, which form the hepatic plates. Each plate is made up of two columns of cells . In between the two columns of each plate lies a bile canaliculus

8. In between the neighboring plates, a blood space called sinusoid is present. Sinusoid is lined by the endothelial cells. In between the endothelial cells some special macrophages called Kupffer cells are present(It destroy the microorganism in blood).

9. Portal Triads Each lobule is surrounded by many portal triads. Each portal triad consists of three vessels: A branch of hepatic artery A branch of portal vein A tributary of bile duct

10. „ Blood s upply to Liver Hepatic artery It arises directly from aorta and supplies oxygenated blood to liver. „ Portal Vein It brings deoxygenated blood from stomach, intestine, spleen and pancreas. The blood from hepatic artery mixes with blood from portal vein in hepatic sinusoids. Hepatic Vein Central veins from many lobules unite to form bigger veins, which ultimately form hepatic veins (right and left) which open into inferior vena cava.

11. Functions of the liver

12. Functions of the liver 1. Metabolism a)Carbohydrate metabolism Glucose is converted to glycogen for storage and glucagon stimulates conversion of glycogen into glucose (Maintain blood glucose level). b) Fat metabolism Stored fat can be converted to a energy c) Protein metabolism Deamination of amino acids. Transamination Synthesis of plasma proteins

13. 2.Breakdown of erythrocytes and defence against microbes ( Kupffer cells ) 3. Detoxification of drugs and toxic substances – These include ethanol (alcohol), waste products and microbial toxins. This is because after absorption from the alimentary tract, they travel in the blood to the liver where they are largely metabolised so that levels in the blood leaving the liver and which enters the systemic circulation are inadequate to achieve therapeutic effects. This is known as ‘ first pass metabolism’. .

14. 3.Inactivation of hormones like Insulin, glucagon, cortisol , aldosterone, thyroid and sex hormones 4 . Production of heat. 5. Secretion of bile The hepatocytes synthesise the constituents of bile from the mixed arterial and venous blood in the sinusoids. These include bile salts, bile pigments and cholesterol . 6. Storage of substances include: Glycogen Fat-soluble vitamins: A, D, E, K Iron , copper Water-soluble vitamins, e.g. vitamin B12.

15. Bile juice

16. Bile Juice It secrete from Liver Stored in gall bladder Secrete in to Duodenum of Small intestine through Heapto pancreatic ampulla through bile duct. Volume : 800 to 1,200 mL/day

17. COMPOSITION OF BILE Bile contains 97.6% of water and 2.4% of solids. Solids include organic and inorganic substances

18. Functions of Bile juice Bile salt In the small intestine they emulsify fats , aiding their digestion. Fatty acids are insoluble in water, which makes them very difficult to absorb through the intestinal wall. Bile salts make cholesterol and fatty acids more water-soluble, enabling both these and the fat-soluble vitamins (vitamins A, D, E and K) to be readily absorbed .

19. Bile pigment It is the excretory products in bile. Bilirubin and biliverdin are the two bile pigments formed during the breakdown of hemoglobin .

20. Thanking you