What are the three major functions of liver in digestive system?
The liver performs several important functions in the digestive system:
1. Production of Bile: The liver produces bile, a greenish-yellow fluid that aids in the digestion and absorption of fats. Bile is stored in the gallbladder and released into the small intestine when needed. It helps emulsify dietary fats, breaking them down into smaller droplets that can be more easily digested by enzymes. Bile also aids in the absorption of fat-soluble vitamins (vitamins A, D, E, and K).
2. Metabolism of Carbohydrates, Proteins, and Fats: The liver plays a central role in the metabolism of carbohydrates, proteins, and fats.
- Carbohydrate Metabolism: The liver helps regulate blood glucose levels by storing excess glucose as glycogen through a process called glycogenesis. When blood glucose levels drop, the liver can break down glycogen into glucose and release it into the bloodstream (a process known as glycogenolysis) to maintain energy homeostasis.
- Protein Metabolism: The liver is involved in the synthesis of plasma proteins, such as albumin and blood clotting factors. It also breaks down and removes waste products resulting from protein metabolism, including ammonia, which is converted into urea and excreted by the kidneys.
- Fat Metabolism: The liver is responsible for the synthesis and breakdown of fats. It produces lipoproteins, particles that transport fats throughout the body, and also metabolizes fatty acids, producing energy or storing them as triglycerides. The liver plays a crucial role in regulating cholesterol levels and preventing its accumulation in the blood vessels.
3. Detoxification and Storage: The liver acts as a detoxification center for various harmful substances, such as drugs, alcohol, toxins, and metabolic waste products. It metabolizes and breaks down these substances into less harmful or excretable forms, which are then eliminated from the body through urine or feces. The liver also stores essential nutrients, such as vitamins (vitamins A, D, B12) and minerals (iron and copper), and can release them as needed by the body.
These are just a few examples of the many important functions of the liver in the digestive system, underscoring its vital role in overall digestion, nutrient metabolism, detoxification, and maintenance of homeostasis in the body.