Question

Write two functions of liver.

Hint:

To remember the liver's role in digestion, think of it as a detergent: bile does not digest fat chemically; instead, it acts as an emulsifier that breaks large fat droplets into tiny pieces so digestive enzymes can break them down easily.

Answer 1

Step 1: Introduction to Hepatic Physiology:
The liver is the largest internal solid organ in the human body. It acts as a central biochemical processing plant, performing hundreds of vital functions related to digestion, metabolism, detoxification, and protein synthesis.

Step 2: Detailing Two Primary Functions:
Two of the most critical physiological functions of the liver are:

• Bile Production and Secretion (Digestion): The liver continuously synthesizes and secretes bile, a greenish-yellow alkaline fluid containing bile salts, cholesterol, and bilirubin. Bile is stored and concentrated in the gallbladder, then released into the duodenum. Here, bile salts emulsify large fat globules into microscopic droplets, significantly increasing their surface area so they can be digested and absorbed by pancreatic lipase enzymes.
• Metabolic Regulation and Nutrient Storage: The liver plays a central role in maintaining blood glucose homeostasis.
  • When blood glucose is high (after a meal), the liver converts excess glucose into glycogen for storage under the influence of insulin (glycogenesis).
  • When blood glucose drops, the liver breaks down stored glycogen back into glucose (glycogenolysis) or synthesizes glucose from non-carbohydrate sources like amino acids (gluconeogenesis).
  • It also stores fat-soluble vitamins ($A, D, E, K$), vitamin $B_{12}$, and minerals like iron (as ferritin).

Step 3: Alternative Vital Functions (For Reference):
Other essential hepatic functions include detoxification (converting toxic ammonia into urea, metabolizing alcohol and drugs) and the synthesis of plasma proteins (such as albumin and blood clotting factors like prothrombin).