what is the flora of the large intestine
Gut flora The small intestine contains a trace amount of microorganisms due to the proximity and influence of the stomach. Gram-positive cocci and rod-shaped bacteria are the predominant microorganisms found in the small intestine.[2] However, in the distal portion of the small intestine alkaline conditions support gram-negative bacteria of the Enterobacteriaceae.[2] The bacterial flora of the small intestine aid in a wide range of intestinal functions. The bacterial flora provide regulatory signals that enable the development and utility of the gut. Overgrowth of bacteria in the small intestine can lead to intestinal failure.[26] In addition the large intestine contains the largest bacterial ecosystem in the human body.[2] About 99% of the large intestine and feces flora are made up of obligate anaerobes such as Bacteroides and Bifidobacterium.[27] Factors that disrupt the microorganism population of the large intestine include antibiotics, stress, and parasites.[2]
Large intestine Most sources define the large intestine as the combination of the cecum, colon, rectum, and anal canal.[2][3] Some other sources exclude the anal canal.[4][5][6]
Small intestine Absorption of the majority of nutrients takes place in the jejunum, with the following notable exceptions:
Human microbiota The gut flora has the largest numbers of bacteria and the greatest number of species compared to other areas of the body.[6] In humans the gut flora is established at one to two years after birth, and by that time the intestinal epithelium and the intestinal mucosal barrier that it secretes have co-developed in a way that is tolerant to, and even supportive of, the gut flora and that also provides a barrier to pathogenic organisms.[19][45]