The digestion system is a crucial point of study to understand the digestive mechanism and also the digestive disorders. From the chewing mechanism in our mouth to the removal of feces from the rectum, everything participating organ is part of the digestive system. The digestive system of humans and rats, though goes through the same mechanism, differs anatomically.
Human Digestive System vs Rat Digestive System
The main difference between the human digestive system and rat digestive system is that the human digestive system has a gallbladder where the bile juice is transferred from the liver. On the other hand, rats don’t have a g gallbladder. Rats have a separate fermentation chamber for cellulose digestion but they are absent in the human digestion system.
The digestive system of humans constitutes the gastrointestinal tract (GI tract) along with the liver, pancreas, and gallbladder. The GI consists of a series of hollow organs that start from the mouth to the anus. While the liver pancreas and gallbladder are the solid organs in the human digestive system, the hollow organs are the mouth, esophagus, stomach, small and large intestine, and anus.
Rats belong to the order Rodentia and there are only a few distinct features apart from which their digestive system is similar to that of humans. Rats have a different dental formula than humans and don’t grow any wisdom teeth upon aging. They have an alimentary canal starting from mouth to anus but lack a gallbladder.
Comparison Table Between a Human Digestive System and a Rat Digestive System
| Parameters of Comparison | Human Digestive System | Rat Digestive System |
| Teeth | Humans have eight incisors, four canines, eight premolars, and twelve molars that includes four wisdom teeth. | Rats have twelve molars and four front teeth and they are also growing. So, rats need to shave them down. |
| Digestion Time | It takes 36 hours in a human body to move the food through the entire colon. | Protein digestion takes place in rats over a period of 1-2 hours. |
| Gallbladder | Humans have a gallbladder where the bile juice is stored and concentrated from the liver. | Rats do not have gallbladders. |
| Fermentation | Humans do not have a separate fermentation chamber. | Rats have a separate fermentation chamber for digesting cellulose. |
| Large Intestine | Humans don’t have an enlarged large intestine and it is 6 feet long. | Rats have an enlarged large intestine. |
| Digestive Disorders | Common digestive disorders in humans are constipation, ulcers, hemorrhoids, diarrhea, and gastroesophageal reflux disease. | Pinworms are commonly found as intestinal parasites in rats and heavy infection leads to intestinal inflammation. |
| Feces | The color of human feces changes according to the type of food one consumes and the amount of bile present in the stool. | Rate feces are black and they are a common source of hantavirus. |
What is a Human Digestive System?
In the GI tract of our digestive system, many types of bacteria are present that assist in the process of digestion. The digestive system helps to break down the food particle into very small particles so that our bodies can absorb and use the energy for various purposes. For example, protein break into amino acid, fats into fatty acids and glycerol, and carbohydrates into simple sugars.
The hollow organs in our digestive system are also further divided into subparts. For example, the small intestine is divided into three parts, duodenum, jejunum, and ileum. The large intestine is comprised of four parts, namely, appendix, caecum, colon, and rectum. The appendix is a finger-shaped pouched which can be removed with the help of surgery when it is infected. The human digestive system, esophagus, small intestine, and large intestine are responsible for peristalsis movement. The digestive juices are produced in the stomach and mixed with food. This mixture is then called chyme which is transferred to the small intestine.
The juice secreted from the pancreas helps in the breakdown of carbohydrates, fats, and proteins while the liver secrets bile helping in the digestion of fats and some vitamins. The bile that is secreted is stored in the gallbladder between the intervals of meals and then transferred to the small intestine. Stool formation takes place in the large intestine.
What is a Rat Digestive System?
The digestive system of rats consists of the alimentary canal and the digestive glands. The alimentary canal is a long tube that starts from the mouth and continues to the rectum. The functions of this tube in different regions are different. Rats have 16 teeth in total and the upper lip has a cleft in the middle. The front teeth, i.e., the incisors are visible from the outside. The dental formula of a rat is 1.0.0.3/1.0.0.3.
The stomach of a rat is similar to that of a human in the sense it also secrets digestive juices and takes part in indigestion. Although the entire process of digestion in rats takes less time than the human digestive system. After the stomach, there is a small and large intestine. The large intestine of the rat is quite enlarged unlike that of humans.
In rats, there is no gallbladder in their digestive system for storing and concentrating bile juice. So, the digestive glands that contribute to the process are salivary glands, liver, pancreas, gastric glands, intestinal glands, and spleen. The feces of a rat can contain many harmful viruses. For example, it may contain hantavirus which then mixes into the air and affects the lungs of human beings.
Main Differences Between a Human Digestive System and a Rat Digestive System
- Humans have a total of 32 teeth (including four wisdom teeth) whereas rats have a total of 16 teeth and they grow throughout their life span.
- It takes 36 hours in a human body to move the food through the entire colon whereas the protein in rats takes only 1-2 hours for digestion.
- Humans have a gallbladder where the bile is stored and concentrated but in rats they are absent.
- Humans do not have a separate fermentation chamber whereas rats have one for digestion of cellulose.
- Humans don’t have an enlarged large intestine and it is 6 feet long but rats have an enlarged large intestine.
- The color of human feces changes according to the type of food one consumes and the amount of bile present in the stool whereas rats have black solid droppings.
Conclusion
Various digestive juices and enzymes help in the process of digestion along with the movement of muscles (peristalsis). Mouth (teeth, salivary glands, etc) plays a crucial role in digestion as it helps in mastication. The small intestine absorbs most of the nutrition and rest is transferred to the large intestine leading to discharge.
In humans, the type of diet has an important role in digestion time. The average time of digestion is 36 hours but it can take less than that as well. Sometimes improper diet, eating quickly without chewing, or skipping meals can cause several digestive disorders.
References
- https://europepmc.org/article/med/30684346
- https://link.springer.com/article/10.1007/BF01946561