Hydrochloric Acid

Gastric juice contains a high concentration of which substance?

Hydrochloric acid

How low can the pH of gastric juice go?

0.8

Which cells are responsible for producing hydrochloric acid (HCl) in the stomach?

Parietal Cells

What enzyme is found in parietal cells and helps produce hydrogen ions?

Carbonic anhydrase (CAH)

What is the correct sequence of the reaction catalyzed by carbonic anhydrase?

CO₂ + H₂O → H₂CO₃ → HCO₃⁻ + H⁺

How are hydrogen ions (H⁺) transported into the gastric gland lumen?

H⁺-K⁺ ATPase pump

What does the H⁺-K⁺ ATPase pump do?

Pumps H⁺ out and K⁺ in using ATP

During the chloride shift, what is exchanged across the cell membrane?

HCO₃⁻ for Cl⁻

What happens to chloride ions (Cl⁻) after entering the parietal cell?

They are pumped into the lumen of gastric gland to join H+ forming HCl

What effect does elevated bicarbonate (HCO₃⁻) in the blood have?

increasing blood pH (alkaline tide)

What is one role of hydrochloric acid in enzyme activity within the stomach?

It causes the release and activation of pepsin

How does hydrochloric acid assist in the breakdown of food structures?

It breaks up connective tissues and plant cell walls

Why is the highly acidic (low pH) environment of the stomach important?

It destroys most bacteria and pathogens

Why does salivary amylase stop working in the stomach?

It works best at neutral pH and becomes inactive in acidic conditions

What is the result of salivary amylase being inactivated in the stomach?

Carbohydrate digestion that began in the mouth stops