LIVER

The liver is situated in the upper right part of the mid-region. It is the largest organ in the human body that fills a few significant roles. The main organ can recover productively.

LIVER
LIVER


Anatomy Of Liver

Structure Of Liver

  1. Origin:- Endoderm. 
  2. Location:– Upper right side of the abdominal cavity just below the diaphragm. 

Made up of two lobes 

  1. Left Lobe (1/6) 
  2. Right Lobe (5/6) 
  • Weight:- 1.2 to 1.5 kg
  • Lobes are separated by Falciform ligament (folds of peritoneum and fibrous connective tissue)    

Hepatic lobules are the structure and functional unit of liver
Hepatic lobules
Hepatic lobules


Structural and functional units of the liver containing hepatic cells arranged in the form of cords. Glisson's capsule covering of the hepatic lobule is made up of thin connective tissue (sheath).

The bile secreted by the hepatic cells passes through the hepatic ducts and is stored and concentrated in a thin muscular sac called the gall bladder.

The duct of the gall bladder (cystic duct) along with the hepatic duct from the liver forms the common bile duct The bile duct and the pancreatic duct open together into the duodenum as the common hepato-pancreatic duct. which is guarded by a sphincter called the sphincter of Oddi


Gall bladder 

The gall bladder is situated below the right lobe of the liver. The gall bladder is not present in lamprey, whales, and horses. The cystic duct of the gall bladder is connected to the common hepatic duct to form a common bile duct also called ductus choledocus.

LIVER (FUNCTION) 

  1. Carbohydrate metabolism
  2. Synthesis and secretion of Bile Juice
  3. Hemopoiesis
  4. Kupffer Cells (Macrophages of Liver) Phagocytose microbes help in the purification of blood
  5. Detoxification, Deamination, Urea formation  
  6. Storage of Vit. A, D, E, K, B12, Fe, Cu, Zn, Co, Mo and small quantities of Fat (Increased in Liver Cirrhosis)
  7. Synthesis of 
  • Plasma Proteins 
  • Heparin 
  • Clotting Factors  


Secretion & synthesis of bile 

Secreted by Hepatocytes in Liver. 

Stored and concentrated in Gall Bladder.  

Digestive enzymes are absent in Bile (Pseudo-digestive juice). 

Composition of Bile Juice:- 

  1. pH – 8.0 
  2. Water – 98% 
  3. Organic Constituents  
  4. Inorganic Constituents – Na+ , K+ , Cl − , HCO3 − 
  5. Bile Salts 
  6. Cholesterol 
  7. Lecithin
  8. Bile Pigments 
  • Bilirubin(Yellow) 
  • Biliverdin(Green)

Bile Juice
Bile Juice


Emulsification
Emulsification


Bile Juice

  1. Excretion of Bile pigments, Cholesterol and Lecithin
  2. Prevent decomposition of food
  3. Stimulation of Peristalsis
  4. Absorption of Fat and Fat-soluble vitamins (Vit. A, D, E, K) 
  5. Emulsification of Fat 
  6. Neutralization of HCl 
  7. Activation of Lipase 


CARBOHYDRATE METABOLISM


CARBOHYDRATE METABOLISM


Storage of fats

Liver stores fats in small amounts. Hepatic cells play an important role in fat metabolism. The storage of fat increases in the liver of alcohol addict persons (Fatty liver). This stored fat decreases the activity of the liver. The damage to the liver due to alcohol intake is called Alcoholic Liver cirrhosis.



Deamination and Urea formation 


Deamination of amino acids is mainly done by the liver (Amino acid➡ NH3) Liver converts ammonia (more toxic) into urea (less toxic) through the ornithine cycle. With the spoilage of the liver, the ammonia level in the animal body increases, and ultimately the animal dies


Purification of blood 

Kupffer cells of the liver & splenocytes of the spleen are the phagocytic celhelpelps in the phagocytosis of dead blood cells and bacteria from the blood.


Synthesis of plasma proteins

Many types of proteins are present in blood plasma. All the proteins except Gama-globulins are synthesized in the liver. Chemically antibodies gamma globulins are formed by lymphocytes.


Synthesis of Heparin

Heparin is a natural anticoagulant (mucopolysaccharide). Some heparin is also formed by basophils (granulated WBC) and mast cells.


Synthesis of Vitamin-A


The liver changes b-carotene into vitamin –A, b- carotene is a photosynthetic pigment that is obtained from the yellow part of fruits. It is abundantly found in carrot


 Liver stores vitamins A,D,E,K,B12


Storage of minerals

The liver stores iron, copper, zinc, cobalt, molybdenum, etc. The liver is a good source of iron.


Haemopoiesis

The formation of blood cells is called Haemopoiesis. In the embryonic stage, R.B.C and WBC are formed by the liver


Secretion of enzymes

Some enzymes are secreted by the liver, participate in the metabolism of proteins, fats, and carbohydrates e.g. Dehydrogenase, cytochrome oxidase, etc


Prothrombin and fibrinogen proteins are also formed in hepatic cells. These help in blood clotting.

Factors I, II, V, VII, IX, and X are formed in the liver, which is responsible for blood clotting


NOTE : Deficiency of selenium, causes liver necrosis.