a) The walls of the stomach are protected against corrosion of hydrochloric acid by a layer of mucus that coats the inner lining of the stomach. This mucus layer acts as a physical barrier between the stomach walls and the acidic environment inside the stomach. It prevents direct contact of the hydrochloric acid with the stomach lining and prevents corrosion or damage to the cells.
Additionally, the stomach lining contains specialized cells called goblet cells that produce and secrete bicarbonate ions. Bicarbonate ions act as a buffer and help neutralize the hydrochloric acid, reducing its corrosive effects on the stomach walls.
b) The walls of the stomach are protected against digestion by protein enzymes through the secretion of an enzyme called pepsinogen. Pepsinogen is secreted by specialized cells in the stomach lining called chief cells. When pepsinogen comes into contact with the acidic environment of the stomach, it is converted into its active form called pepsin.
Pepsin is a protein enzyme that is responsible for the digestion of proteins in the stomach. However, the stomach lining itself is made up of proteins, and if pepsin were to digest these proteins, it would lead to damage and erosion of the stomach walls. To prevent this, the stomach lining simultaneously secretes mucus and bicarbonate ions, which form a protective barrier against pepsin activity.
Furthermore, the stomach lining has a rapid turnover rate, meaning that its cells are constantly regenerating and replacing damaged cells. This continuous renewal of the stomach lining helps protect it from the potential damaging effects of pepsin.
Explain how the walls of the stomach are protected against;
a) corrosion of hydrochloric acid
b) digestion by protein enzymes
1 answer