The key difference between digestion in stomach and digestion in intestine is the type of digestion that takes place. In stomach, both chemical and mechanical digestion of foods takes place whereas, in intestine, only chemical digestion takes place.
Digestion is the process by which animals absorb nutrients after ingestion of food. Digestion involves both chemical and mechanical processes. The digestive system of higher level organisms such as humans comprised of various organs. Each of these organs has a major role to play in the process of digestion. Digestion in the stomach refers to both chemical and mechanical digestion of food that takes place in the abdomen or the stomach. Digestion in the intestine refers to the chemical digestion processes that take place in the small intestine. Following digestion, the breakdown products absorb into the bloodstream via the small intestines as well.
CONTENTS
1. Overview and Key Difference
2. What is Digestion in Stomach
3. What is Digestion in Intestine
4. Similarities Between Digestion in Stomach and Digestion in Intestine
5. Side by Side Comparison – Digestion in Stomach vs Digestion in Intestine in Tabular Form
6. Summary
What is Digestion in Stomach?
Digestion in the stomach takes place chemically and mechanically. The gastric juice that secreted from the stomach initiates the digestion process. The chemical digestion process in the stomach mainly is mediated by the gastric juice and other enzymes. Accordingly, the gastric juice contains hydrochloric acid as its main component. Consequently, this creates an acidic environment that aids in digestion. In addition to the gastric juice, another enzyme called pepsin involves in the stomach digestion process by degrading proteins into amino acids. Furthermore, stomach secretes gastric lipase, which breaks down fat into glycerol and fatty acids. In addition, digestion of milk protein, casein also takes place in the stomach with the action of renin.
Figure 01: Digestion in Stomach
The mechanical digestion process in the stomach is characterized by the continuous peristaltic movements that take place in the stomach. Stomach walls facilitate these peristaltic movements. Accordingly, the continuous muscular contractions that take place in the stomach forms the food into a chyme which stored in the stomach for 2 – 3 hours.
What is Digestion in Intestine?
Digestion in the intestine strongly limited to chemical digestion. Thus, the digestion is totally carried out by the enzymatic actions. In contrast to the stomach, small intestine has an alkaline pH. This is done by the secretion of bicarbonates to the small intestine. There are many enzymes acting on the intestines including zymogen enzymes such as trypsinogen and chymotrypsinogen. These act on the proteins to break down the proteins to simpler amino acids. In addition to that, lipases break down the lipids into simpler fatty acids, and glycerols and nucleases break down the nucleic acids to its monomers. Therefore, the completion of digestion takes place in the small intestine.
Figure 02: Digestion in Small Intestine
In the later anatomical parts of the small intestine, the absorption of the digested food takes place. This takes place from the villi structures that are present in the small intestine. The absorption of the final breakdown products of digestion to the bloodstream is yet another function of the small intestine. In addition, the fatty acids are packaged into chylomicrons and absorbed into the bloodstream. In comparison to small intestine, the large intestine does not undergo any digestion process. It is the main organ which absorbs water.
What are the Similarities Between Digestion in Stomach and Digestion in Intestine?
- Digestion in stomach and digestion in intestine are mediated by chemicals such as enzymes.
- These digestion processes take place in organisms which have a developed complete digestive tract.
- Also, the pH govern both digestion processes.
- Furthermore, the hormonal activity involves in both digestion processes.
- Both stomach and small intestine secrete zymogens.
What is the Difference Between Digestion in Stomach and Digestion in Intestine?
Digestion takes place in different organs of the digestive tract. Stomach and small intestine are two such places where digestion happens. Digestion in stomach occurs in an acidic pH while digestion in small intestine occurs in alkaline pH. This is one major difference between digestion in stomach and digestion in intestine. Also, a key difference between digestion in stomach and digestion in intestine is that the digestion in stomach is a mechanical and chemical process while digestion in intestine is totally a chemical process.
The below inforgraphic on difference between digestion in stomach and digestion in intestine shows more comparisons between both.
Summary – Digestion in Stomach vs Digestion in Intestine
Digestion is an essential process in living beings. Higher organisms have a complete digestive tract. Hence, digestion occurs in several organs of the digestive tract. Digestion in the stomach comprises of both mechanical and chemical digestions processes. In contrast, digestion in the intestine is limited to chemical digestion. Digestion in both sites is regulated by the pH. The acidic pH of the stomach facilitates digestion in the stomach. In contrast, alkaline pH of the intestines facilitates digestion in the small intestine. Hence, this summarizes the difference between digestion in stomach and digestion in intestine.
Reference:
1.Collins, Jason T. “Anatomy, Abdomen and Pelvis, Small Intestine.” StatPearls [Internet]., U.S. National Library of Medicine, 12 Sept. 2018. Available here
2.“Your Digestive System.” WebMD, WebMD. Available here
Image Courtesy:
1.”Digestive system diagram en”By Mariana Ruiz, Jmarchn – Own work, (Public Domain) via Commons Wikimedia
2.”Blausen 0817 SmallIntestine Anatomy”By Blausen.com staff (2014). “Medical gallery of Blausen Medical 2014”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. – Own work, (CC BY 3.0) via Commons Wikimedia