Notes On Digestion in Ruminants - CBSE Class 7 Science
Animals which feed on plants are called as herbivorous animals. Plant cells contain rich content of cellulose. Cellulose is an important component in the diet of herbivorous animals. Humans cannot digest cellulose.                                                                                        Ruminants: These are also called as grass-eating animals. These are hoofed animals whose body stands on four limbs. Ruminants include, cows, buffaloes, sheep, giraffe, camel, deer etc. They also possess special type of digestive tract which extracts nutrition from the food they eat. Dentition in ruminants: Dentition is quite different in rumination. Incisors are absent on the upper jaw. Canines are absent in both the jaws. Molars are very strong as these animal chew the cud.  Rumination: Ruminants swallow the food without chewing. After feeding, they bring the food from the stomach back into the mouth and chew it leisurely. This process is called rumination and such animals are called as ruminants. Rumination is also called second chewing. Ruminant stomach: The stomach of a ruminant is divided into four chambers – the rumen, reticulum, omasum and abomasum. Rumen is the largest part of the stomach.  Process of digestion: Grass-eating animals swallow the food quickly and store it in the rumen.  Rumen also inhabits cellulose digestic bacteria which establish a symbiotic relationship with the animal stomach. Digestion in ruminants is a good example of symbiosis.Microorganisms present in the stomach of ruminants help in digesting cellulose and in turn obtain shelter and nourishment form the animal. A symbiotic relationship exists between microorganisms and the ruminants.  As rumen is full, the food is taken into second part of the stomach, the reticulum. Digestive juices of the reticulum partially digest the food. The partially digested food in the reticulum is called as cud. While resting, cow brings back the cud into the mouth for regurgitation. Food is chewed completely and swallowed into omasum for further digestion. Then the food moves into abomasum for digestion brought about by digestive juices. A large sac-like structure called the caecum lies between the small and large intestines. The symbiotic bacteria present in the caecum help in complete digestion of cellulose. Digestion of food is completed in the intestine. As the symbiotic bacteria are not present in the human digestive system, humans cannot digest cellulose.

#### Summary

Animals which feed on plants are called as herbivorous animals. Plant cells contain rich content of cellulose. Cellulose is an important component in the diet of herbivorous animals. Humans cannot digest cellulose.                                                                                        Ruminants: These are also called as grass-eating animals. These are hoofed animals whose body stands on four limbs. Ruminants include, cows, buffaloes, sheep, giraffe, camel, deer etc. They also possess special type of digestive tract which extracts nutrition from the food they eat. Dentition in ruminants: Dentition is quite different in rumination. Incisors are absent on the upper jaw. Canines are absent in both the jaws. Molars are very strong as these animal chew the cud.  Rumination: Ruminants swallow the food without chewing. After feeding, they bring the food from the stomach back into the mouth and chew it leisurely. This process is called rumination and such animals are called as ruminants. Rumination is also called second chewing. Ruminant stomach: The stomach of a ruminant is divided into four chambers – the rumen, reticulum, omasum and abomasum. Rumen is the largest part of the stomach.  Process of digestion: Grass-eating animals swallow the food quickly and store it in the rumen.  Rumen also inhabits cellulose digestic bacteria which establish a symbiotic relationship with the animal stomach. Digestion in ruminants is a good example of symbiosis.Microorganisms present in the stomach of ruminants help in digesting cellulose and in turn obtain shelter and nourishment form the animal. A symbiotic relationship exists between microorganisms and the ruminants.  As rumen is full, the food is taken into second part of the stomach, the reticulum. Digestive juices of the reticulum partially digest the food. The partially digested food in the reticulum is called as cud. While resting, cow brings back the cud into the mouth for regurgitation. Food is chewed completely and swallowed into omasum for further digestion. Then the food moves into abomasum for digestion brought about by digestive juices. A large sac-like structure called the caecum lies between the small and large intestines. The symbiotic bacteria present in the caecum help in complete digestion of cellulose. Digestion of food is completed in the intestine. As the symbiotic bacteria are not present in the human digestive system, humans cannot digest cellulose.

#### Activities

Activity 1 Csus.edu has formulated a small interactive module to make the user understand the concept of  'Digestion in ruminants'. Though it is a simple module, it makes the concept clear for the student. User needs to follow the instructions and click on the respective parts of the ruminant stomach. Clearcut animation is shown along with the text to explain the role of that part of the stomach in the process of digestion.     Go to Activity Activity 2 Razeghi.ir has devised a template on the concept 'Ruminant digestion'. Click on continue button to enter the interaction. Student has to answer some questions in order to obtain information on the concept. After each step user has to click on the 'Play' button to resume the next step. Ruminant digestion is explained clearly in different steps represented by the slides.   Go to Activity

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