stomach digestion

describe the structure of the stomach

• muscular wall

• gastric glands

• Hydrochloric acid

• Pepsin

• Mucus

What is the function for the muscular wall in the stomach

Thick muscular wall which contracts to mix food with digestive juices(churning)

-contractions help break down food mechanically into smaller pieces - increasing surface area for digestive enzymes to act

What does the gastric glands in the stomach do

Inner lining of stomach has gastric glands which secrete gastric juice

Gastric juice- is a mixture of HCL , pepsin and mucus

What does hydrochloric acid in the stomach do

Creates an acidic environment in stomach which helps to kill bacteria and pathogens that may be present in food

-HCL-also provides optimum pH for pepsin to function effectively

What is the function of pepsin in the stomach

• Pepsin is a protease enzyme that begins the digestion of proteins by breaking them down into smaller peptides.

• Pepsin is secreted in an inactive form called pepsinogen, which is activated by the acidic environment.

What is the function of mucus in the stomach

• The stomach lining is protected by a layer of mucus, which prevents the stomach from digesting itself and protects against the corrosive effects of the acid.

What is the function of the stomach

1. Mechanical Digestion:

• The stomach's muscular walls mix and churn food, breaking it down into a semi-liquid form known as chyme.

2. Chemical Digestion:

• Gastric juice, containing HCl and pepsin, starts the chemical breakdown of proteins into smaller peptides.

• The acidic environment helps denature proteins, making them easier to digest.

3. Temporary Storage:

• The stomach serves as a temporary storage site for food, releasing it gradually into the small intestine for further digestion and absorption.

4. Protection:

• The stomach's acidic environment helps kill harmful bacteria and pathogensthat may be ingested with food.

What happens in the stomach in the digestive system

• After food is swallowed, it enters the stomach from the oesophagus through a valve called the lower oesophageal sphincter.

• Food is then mixed with gastric juices in the stomach.

• The partially digested food (chyme) is gradually released into the duodenum(the first part of the small intestine) through another valve called the pyloric sphincter.