Digestion Series: Part 3 - Stomach

Now that you have chewed your food that is lubricated with #saliva and amylase #enzymes are breaking down the starches and sugars, it makes its way to the acidic environment of the stomach via the esophagus.

What is the role of our #stomach? It is to store food and further process it prior to delivering it to our small intestine. There are a number of both physical and chemical modifications to the food that occur.

Note that while the stomach is not considered a major organ where #absorption into the body occurs, some water and lipid (fat)-soluble substances are absorbed such as ethanol (alcohol) and some short- and medium-chain fatty acids.

Rather than focusing on absorption of nutrients, the stomach works to create "chyme", which is a thick semi-fluid mass of partially digested food and digestive secretions. It is #chyme that gets passed on to the small intestine to be broken down even further.

Let's talk now about the anatomy of the stomach, starting with the gastric mucosa.

The #gastricmucosa is a mucous membrane layer found on the inner surface of the stomach. It contains glands and gastric pits, and is covered in a layer of thick mucus secreted by epithelial and glandular cells.

Its key function is to help create an environment in the stomach where ingested food can be exposed to enzymes and #acids.

The gastric mucosa serves two primary purposes: 1) to lubricate the food masses in the stomach and facilitate movement into the small intestine, and 2) to create a protective barrier to protect the stomach wall from acid and digestive enzymes. Essentially, the gastric mucosa is vital in the creation of chyme, while its #barrier function protects the stomach from strong acids.

The #gastric juice secreted by the stomach contains hydrochloric acid, which is at a very low pH and is typically extremely corrosive. However, in the stomach, it only works to kill any ingested bacteria, soften food, and promote the formation of #pepsin, which is a digestive enzyme that breaks down proteins.

In the next post, we'll talk about how the stomach breaks down #protein found in food.