Translations:Benutzer:Arian/Klett-Mini-Test/608/en

Small and Large Intestine Digestion

As the plant forms dissolve in the digestive tract, the formative forces are gradually released from their material confinement. This is the result of a step-by-step breakdown process that unfolds in three phases: a mechanical-to-microbial phase from chewing through to the rumen and psalterium activity; a predominantly enzymatic, though also bacterial phase from the abomasum through the jejunum to the ileum; and from there a purely microbial phase from the caecum through the colon to the rectum. While in the forestomachs the opening-up of cellulose is the governing process — and alongside it, through the extraordinarily active microbial life, a re-building and up-building protein metabolism takes place — protein breakdown begins in the abomasum (Abomasum), in the acid medium brought about by the gastric acids. This continues, taking in the dead microbial masses from the forestomachs, along enzymatic and bacterial pathways through the sections of the small intestine (Intestinum tenue): first through the secretions of the pancreas (Pancreas), which, like the bile that emulsifies fats, empty into the duodenum (Duodenum); then through the jejunum (Jejunum), set with countless glands and villi; and through the short ileum (Ileum). The latter forms a sluice between the jejunum and the large intestine. It prevents backflow from the bacterially rich contents of the colon and rectum into the bacterially poor jejunum. Altogether the small intestine reaches a length of up to 48 metres in the fully grown cow. It hangs in rich convolutions from the mesentery (Mesenterium) — a fold-rich double lamella of serosa. Mesentery and small intestine encircle, like a wreath, the in-winding and out-winding spiral of the colon, which, joining and opening into the caecum and ileum and then into the large intestine or rectum, forms the third section. What has passed through rumen and jejunum undigested, in the way of raw-fibre-rich feed mass, is now subjected once more to an intensive microbial breakdown. A not inconsiderable remainder of undigested raw fibre, permeated by a still active microbial mass, appears finally as the cowpat. The question is whether this microbially enlivened, material residue alone makes up the manuring value of cattle dung.