Digestion Part 1 SBI3U

The stomach has four distinct layers that perform specific functions in digestion.

The mucosa is the innermost layer of the stomach, responsible for secreting gastric juices and protecting the stomach lining.

The submucosa layer of the stomach contains nerves and blood vessels that support the functions of the mucosa and muscularis layers.

The muscularis layer of the stomach consists of smooth muscles that contract to churn and mix food with gastric juices.

The serosa is the outermost layer of the stomach, which holds it in place and secretes a lubricating fluid to reduce friction.

Chemical digestion in the stomach is regulated by enzymes, hormones, and nerves working together to break down food.

Gastrin is a hormone released into the bloodstream that stimulates gastric cells to produce more gastric juices.

The gastroesophageal sphincter is located where the esophagus meets the stomach, controlling the passage of food.

The gastroesophageal sphincter relaxes to allow food to enter the stomach from the esophagus.

Chyme is the semi-liquid substance formed by the mixing of food with gastric juices in the stomach.