Explain Gut secretions - External Defence Mechanism
From the saliva and respiratory tract, bacteria reach the gut, here they are killed by the hydrochloric acid and proteolytic enzymes of the gastric juices. They are capable of killing the microbes. If they further escape and reach the large intestine, they are attacked by the gut microbes, which secrete antibiotics that kill many pathogenic bacteria. Note: Hepatitis A virus survives gastric juice.