Difference between rat and human circulatory system
Answers
Rat - Circulatory System. The general structure of the circulatory system of the rat is almost identical to that of humans. Pulmonary circulation carries blood through the lungs for oxygenation and then back to the heart. Systemic circulation moves blood through the body after it has left the heart.
Human-The circulatory system consists of three independent systems that work together: the heart (cardiovascular), lungs (pulmonary), and arteries, veins, coronary and portal vessels (systemic). The system is responsible for the flow of blood, nutrients, oxygen and other gases, and as well as hormones to and from cells.
Since both human and rat are mammals, their digestive systems exhibit many similarities and very few dissimilarities. Usually, in science laboratory sessions, it is the rat digestive system that students are taught, as it is very similar in structure and function. However, a good deep analysis of both human and rat systems would reveal that there exist differences between the two systems. Obviously, human has the physically larger system being the larger animal, and the other significant differences between these two are essential to understand. This article would be a considerable help for anyone who is interested about knowing those differences. As a starting point, consideration of food habits would generally describe the structure and functions of any digestive system.
Rat Digestive System
Rats are predominantly seedeaters, and their digestive system shows special adaptations to digest seeds. As most of the seeds contain cellulose, the rat digestive tract is specialized to digest long polysaccharides. Therefore, there is a specialized chamber to rot the seeds to digest the hard cellulose chains through fermentation. The enlarged large intestine or caecum with microorganisms functions as the fermentation chamber of the digestive system of rats. Interestingly, there is no gall bladder in the rat digestive system. Usually, the enzymes secreted from the gall bladder are responsible for the digestion of animal fats, but rats are neither carnivorous nor omnivorous mostly. Therefore, they do not need to digest animal fats, and the absence of gall bladder explains that. Other than those exceptions, rats have a digestive tract starts with the small oral cavity with salivary glands and ends with the posterior opening.
Human Digestive System
Humans are omnivorous and have a generalized food habit, which means there is no specific food type that is particularly essential to maintain the life of a man. Therefore, the digestive system is not essentially specialized, but it is a simple tract with necessary accessory glands. It starts with the simple oral cavity containing salivary glands, tongue, and teeth to taste and start the digestion of food. Then, the oesophagus, stomach, small intestine with three parts, large intestine, and anus are the main parts of the digestive system performing essential functions in food digestion, absorption, and elimination. However, the accessory glands play an invaluable role in the food digestion as humans consume a variety of foods containing various nutrients. Humans being omnivorous, there are a lot of proteins and fats being ingested and will have to be digested properly. The presence of gall bladder makes sure the digestion of animal fats from the food, as humans are omnivorous in food habit. In addition, humans do not favour to feed on many seeds, unless it is tasty or prepared by softening the hard cellulose parts because, there is no adaptation in human digestive tract to breakdown cellulose.