 Dear students, in this topic, we shall discuss the stomach, which is a storage part of the foregut. The major functions of the stomach are, it acts as the major storage organ of the foregut. It also carries out initial stages of protein digestion. It secretes an enzyme, pepsin, in its inactive form, pepsinogen, in an acidic environment, which is produced by the secretion of hydrochloric acid, or HCl. Stomach has another major function, mechanical treatment of the food, which involves grinding of the contents of food with the muscular contraction of its walls. Grinding also mixes the food with digestive juices. In vertebrates, stomachs produce two major types, which are based on the number of chambers of stomach. Stomachs may be monogastric, stomachs are digastric stomachs. Monogastric stomachs consist of a single strong muscular tube or sac. For example, the stomachs found in carnivores and omnivores. Digastric stomachs are multi-chambered. They are found in ruminant mammals belonging to the order RTO Dactyla. For example, deer, giraffe, sheep, cattle, camel, and llama have digastric multi-chambered stomachs. Digastric stomachs have two major divisions. In hard division, they have two or two chambers. In this way, overall, they have four chambers. But there are two divisions. The first division has fermentation chambers, which are called Roman and reticulum. In the second division, there are omeasomes and eb omeasomes. These chambers have two stomachs, which are basically secretaries. First, we shall discuss the fermentation chambers, Roman and reticulum, which receive the food or vegetation after grazing. Because they are found in herbivores and ruminants, they receive the food or vegetation. Such animals send their food to the Romans during grazing. These chambers act as fermentation chambers. These chambers have a large population of bacteria and protozoans. These microbes ferment the carbohydrate components of the ingested food and cause their extensive digestive breakdown. Omeasome or eb omeasome, which is an omeasome, receives undigested food from the Romans. Along with this, many symbiotic microbes that used to live in the Romans also come into the omeasome. Eb omeasome is the true homolog of the stomach, which is found in non-ruminants as a single chamber. This true stomach is such that it has a secretive role. It secretes the digestive enzymes characteristic of the stomach and also digests some protein part of the food. Dear students, birds stomach is also multi-chambered. It has two chambers. These two chambers are called proventriculus or ventriculus. Proventriculus is actually the true stomach which has a secretive function. Whereas ventriculus is also called gizzard. It is the muscular stomach. Proventriculus is secretory and gizzard has highly muscular grinding chambers. This gizzard has sand, pebbles or stones which stay in it due to swallowing. These stones help in grinding off seeds and grains. Some fishes, insects and daquaport crustaceans' stomachs are also variations of this bird's pattern.