What phase of digestion is the stomach involved in?  Following what?

The stomach is located in between the esophagus and the small intestine.

The stomach secretes protein-digesting enzymes and strong acids to aid in food digestion.

Chyme is digested food.

The stomach releases proteases (protein-digesting enzymes such as pepsin) and hydrochloric acid which kills or inhibits bacteria in the stomach. It also provides acidic pH for the proteases to work.

Masticated food enters the stomach through the esophagus via the esophageal sphincter. The stomach releases proteases and hydrochloric acid which kills and inhibits bacteria. Food is then churned by the stomach through muscular contractions of the wall, reducing the volume of fundus, before looping around the fundus and the body of the stomach as boluses are converted into chyme. Chyme then slowly passes through the pyloric sphincter into the duodenum. Depending on the amount and content of the food, digestion usually takes 40 minutes and up to several hours.

The extraction of nutrients begins in the duodenum.

The empty volume of the stomach is 45ml (adults), 30ml (newborn).

The stomach normally expands to one liter of food but can hold as much as two-three liters.

The stomach cannot “taste” sodium glutamate using glutamate receptors, information is passed to the lateral hypothalamus and limbic system in the brain as a palatability signal through the vagus nerve. The stomach can also sense glucose, carbohydrates, proteins and fats, independently to tongue and oral taste receptors.

Absorption is mainly function of small intestine but some absorption occurs in stomach as well. For example:

–     Water, if the body is too dehydrated.

–     Simple sugars like glucose.

–     Medications like aspirin.

–     Amino acids.

What are peptic ulcers, gastritis, and stomach cancer mainly be caused by?

The stomach is also an organ where emotions are stored. It’s connected to the gastric center, which governs energy flow and distribution through the belly and gut. Choleric emotions like anger, hate, rage and frustration can store in the stomach and cause gastritis, ulcers and stomach conditions. Stress and tension as well as pensiveness, worry and anxiety stagnate the flow of the natural force in the stomach and cause distension, bloating, colic, gas and stomachaches. If choleric and melancholic tensions are accumulated, we may experience anorexia, appetite disorders, giddiness, and nausea.