Liver Physiology

Article by Dr Raghuram Y.S. MD (Ay) & Dr Manasa, B.A.M.S

Capabilities of Liver

Liver carries out many features within the physique. They’re primarily carried out by the hepatocytes (liver cells). It’s mentioned to be chargeable for about 500 completely different features. These features are carried out by the liver in coordination with different methods and organs. About 20% of resting whole physique oxygen consumption is as a result of liver.

The liver performs a serious position within the metabolism of carbohydrates, proteins, amino acids and lipids.

Carbohydrate metabolism 

–        Glycogenesis – The liver synthesizes and shops the glycogen by way of glycogenesis. Glycogenesis is a course of through which glycogen is fashioned from glucose.
–        Glycogenolysis – The liver breaks down the identical glycogen into glucose and releases it into the blood by performing glycogenolysis as and when the physique wants glucose.
–        Gluconeogenesis – The liver takes half within the synthesis of glucose from some sorts of amino acids, lactate or glycerol. Fats is damaged down by liver cells and adipose and glycerol is produced. This glycerol is utilized by the liver for gluconeogenesis.
–        Gluconeogenesis – This can be a course of through which the liver synthesizes glycogen from lactic acid.

Protein metabolism 

All – protein metabolism, synthesis and degradation are carried out by the liver. The liver is chargeable for synthesizing all of the plasma proteins besides gamma-globulins and a big a part of amino acid synthesis. It additionally produces clotting elements and pink blood cells. Thrombopoietin which regulates the manufacturing of platelets by the bone marrow is produced majorly within the liver.

Lipid Metabolism

Liver is concerned within the ldl cholesterol synthesis, lipogenesis and triglyceride manufacturing. Main elements of the physique’s lipoproteins are synthesized within the liver.

Digestion of meals

Liver additionally performs a most important position within the technique of digestion of meals. It produces and excretes bile. Bile is required for emulsifying the fat and likewise helps in absorption of vitamin Ok from the food regimen. Some a part of the bile is drained instantly into the primary a part of the small gut i.e. duodenum and a few a part of it’s saved within the gallbladder.

Different features of the liver

Progress issue

Insulin like progress issue 1 is a hormone which performs an essential position in childhood progress. Additionally it is produced within the liver. This issue continues to have its anabolic results even in adults.

Liver is reservoir of blood

It’s a storehouse / reservoir of blood. Liver shops giant portions of blood in its blood vessels since it’s an expandable organ. Roughly 10% of the physique’s whole blood quantity is discovered within the hepatic veins and hepatic sinuses. The liver expands as a result of backpressure precipitated because of excessive stress in the correct atrium of the center and half to 1 litre of additional blood is sometimes saved within the hepatic veins and sinuses. This occurs in cardiac failure with peripheral congestion. In response to Wikipedia the liver is a big and expandable venous organ. It acts as a blood reservoir in occasions of extra blood quantity. It additionally provides further blood when the blood quantity is diminished. 

Drug metabolism

It’s concerned in drug metabolism whereby it breaks down or modifies poisonous substances and most medicinal merchandise.

Urea cycle

It converts ammonia into urea (urea cycle) and that urea is excreted in urine.

Lymph manufacturing

Roughly half of all of the lymph which is fashioned within the physique beneath resting circumstances arises within the liver. This occurs because of excessive permeability of the liver sinusoid epithelium.

Shops essential elements

Liver permits storage of vitamin A, D, B12, Ok and E and likewise copper, iron, zinc, cobalt and molybdenum. 

Haemopoietic organ

Liver is a haemopoietic organ. It types RBC and WBC within the embryonic stage. It types RBC within the fetus within the first trimester.

Blood air purifier

It purifies the blood. The Kupffer cells are concerned in phagocytosis of useless blood cells and micro organism from the blood.

Immunological results

The mononuclear phagocyte system current within the liver includes many immunologically lively cells. It acts as a sieve for antigens and therefore is chargeable for immunological results.

Produces albumin

Albumin, the protein within the blood serum, is produced by the liver. It maintains oncotic stress and permits transport of steroid hormones and fatty acids.

Liver helps in

–        It breaks down insulin and different hormones.
–        It breaks down bilirubin and facilitates its excretion into bile.
–        It breaks down and excretes many waste merchandise.
–        Hydrogen peroxide is damaged down into water and oxygen by the catalase enzyme produced by the liver. Hydrogen peroxide is a poisonous oxidizing agent.

Synthesizes angiotensinogen

Angiotensinogen, a hormone which raises the blood stress as a response to the activation by renin, is synthesized by the liver. Renin is an enzyme which is launched by the kidney when it senses low blood stress.

Liver Regeneration

The specialty of the liver is that it’s the solely human inside organ which has the capability to regenerate its misplaced tissues. A whole liver might be regenerated from as little as 25% of liver. Bot being a real regeneration, it’s only a compensatory progress in mammals. No matter lobes have been eliminated won’t regrow. The expansion of liver shouldn’t be that of its authentic kind however is a restoration of perform.

Physiology of Liver – Ayurveda Perspective

In Ayurveda, the liver is known as Yakrit.

On the stage of Raktadhara Kala i.e. the membranes or layers of liver (and spleen) which participate within the formation of blood cells in good high quality and amount.

Being a Raktashaya, together with spleen, the liver acts as a reservoir of blood.

Being part of the roots of raktavaha srotas – the channels of conveyance of blood within the physique, the liver together with spleen is chargeable for distribution of blood to the blood conveying channels.

Being an abode / seat of Ranjaka Pitta, the liver, together with spleen takes half within the motion of ‘rasa ranjana’ i.e. colouring the rasa tissue getting into them into pink color and reworking it into rakta – blood tissue. It additionally imparts color to the faeces and urine.

Associated Studying – Yakrit Kriya Shareera – Physiology of Liver, Ayurveda Perspective