In biochemistry, a consecutive series of chemical reactions (where the product of one reaction is the reactant of the next reaction) form metabolic pathways. These reactions are often catalyzed by protein enzymes.hemical reactions happen at a characteristic reaction rate at a given temperature and chemical concentration.
The digestive system of an ascarid consists of four parts: Alimentary Canal, Mouth, Pharynx, and Intestine. The alimentary canal compromises a short pharynx or esophagus representing the foregut, a long intestine or mod-gut, and a short rectum or hind gut.he stomodeum consists of the âmouth and lipsâ, buccal cavity, and the pharynx (esophagus). Each of these regions are used extensively in taxonomy as well as classification of nematodes, and for providing as indication of feeding habit or trophic group.
alimentary canal see alimentary canal. anal canal the terminal portion of the alimentary canal, from the rectum to the anus. atrioventricular canal the common canal connecting the primordial atrium and ventricle; it sometimes persists as a congenital anomaly.birth canal the canal through which the fetus passes in birth.he terminal portion of the alimentary canal, from the rectum to the anus. atrioventricular canal. the common canal connecting the primitive atrium and ventricle; it sometimes persists as a congenital anomaly. birth canal. the canal through which the fetus passes in birth.