The Digestive System Of Animals Essay

986 Words Oct 17th, 2016 4 Pages
Ruminant species, such as cows, deer, and sheep, have multi-compartmented stomachs. The digestive system starts at the mouth which breaks down the food mechanically. Cows spend around one third of their day grazing and then one third of their day ruminating. The teeth grind the food and saliva is produced to help the food travel down the oesophagus. The saliva contains salivary lipase to break down fat. It also contains the enzyme salivary amylase to break down starch. A bolus is formed when the saliva, containing potassium, sodium, bicarbonate and phosphate is mixed with the food. The bolus then enters the rumen via the oesophagus, which pushes the bolus down using muscle contractions. Ruminants barely chew their food, hence why they have a hard/soft palate without incisors forming the top jaw, which grinds against the incisors on the lower jaw. Therefore the oesophagus allows the food to be brought up again so that the cow can chew it more. The food is then mixed with saliva and is swallowed again. The regurgitated food is then transported to the first chamber of the stomach. The repetitive process of chewing is called chewing the cud. The first chamber of the stomach is the rumen, which consists of papillae (short projections on the wall of the rumen) for absorption and regular contractions (one to three per minute) to mix the food around. The rumen is a large, anaerobic vat (a large container which holds liquid), where fermentation takes place. A cow’s rumen can…

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