Anatomy and physiology of the digestive system - Master. Doctor. Tran Quang Thao

6.1. Reserve and synthesis functions.

6.2. Metabolic function of the liver.

6.3. Honey creation function.

6.4. Anti-toxic function.

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6. FUNCTIONS OF THE LIVER

6.1. Reserve and synthesis functions.

6.1.1. Blood reserves:

6.1.2. Iron reserves:

6.1.3. Vitamin reserves: A, D, B12

1. Blood reserve:

– About 1,000ml of blood from the portal vein and 400ml of blood from the artery

liver enters the liver every minute, accounting for 29% of cardiac output

– The amount of blood contained in the liver is normally quite large (about 600 - 700ml).

When blood pressure in the hepatic vein increases (infusion, after meals, drinking a lot of water...), the liver can expand to hold an additional 200 - 400ml.

– Conversely, when the body is active or when blood volume decreases, the liver will contract.

again, bringing some blood into the circulatory system.

2. Iron reserves:

– The liver is 1/3 of the Fe storage organ, storing 20% of the body's Fe, about 1

g). Amount of Fe from food / from Hb (Hemoglobin) degradation

– When the amount of Fe/blood decreases, the liver will release it into the blood, which is the Fe buffering effect.

3. Reserve vitamins: A, D, B12

- The liver stores the most vitamin A, followed by vitamin D and B12.

- Stock up on enough vitamins for prevention: 10 months for vitamin A, 3-4 months for vitamin B12.

months for vitamin D, at least 12 months for vitamin B12

4. Synthesis of blood clotting factors.

The liver synthesizes fibrinogen and vitamins II, VII, IX and X from vitamin K. When the liver fails, the blood clotting process is disrupted, and the patient is susceptible to bleeding.

6.2. Metabolic function of the liver.

6.2.1. Glucid metabolism.

- The liver has the following functions:

+ Store glucose as glycogen

+ Converts fructose and galactose into glucose

+ Generate new sugars from amino acids and fatty acids, glycerol and lactic acid.

- The liver is involved in maintaining constant blood sugar levels:

+ When blood glucose concentration is high, the liver takes glucose glycogen stores/liver

+ Between meals, blood glucose levels are low, liver: glycogen glucose

+ When glycogen is used up, the liver produces new sugar.

6.2. Metabolic function of the liver.

6.2.2. Lipid metabolism:

- Fatty acid oxide for energy

- Synthesize lipids from carbohydrates and proteins.

- Synthesis of cholesterol, phospholipids and most lipoproteins (VLDL,

LDL, HDL).

6.2.3. Protein metabolism

- Plasma protein synthesis

- Synthesis of non-essential amino acids.

- Urea synthesis to remove NH3

6. FUNCTIONS OF THE LIVER

6.3. Honey creation function.

– Bile is a product secreted by liver cells and then sent to the gallbladder for storage. Here, the bile is concentrated 5-10 times, the gallbladder can store at least 12 hours of secreted bile.

– When reaching the ileum, 95% of bile salts are reabsorbed and then return to the liver through the portal vein and are re-excreted, called the enterohepatic cycle. The remaining 5% of bile salts are excreted in the stool, helping to retain water in the stool and maintain intestinal motility.

6. FUNCTIONS OF THE LIVER

6.4. Anti-toxic function.

– The liver is considered a barrier that protects the body against toxic elements entering through the digestive tract. At the same time, it reduces toxicity and eliminates some substances created during the body's metabolism. The liver's anti-toxic mechanism is carried out by both Kupffer cells and liver cells.

– Anti-poison by 2 mechanisms:

+ Retains some heavy metals such as copper, lead, mercury... and some

colorants such as Bromo-Sulfo-Phtalein (BSP). Then, it will be discharged.

+ Using chemical reactions to convert toxic substances into non-toxic or less toxic substances and then excrete them through the bile duct or kidneys.

Anatomy and physiology of the digestive system - Master. Doctor. Tran Quang Thao - 10

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