Jejunum: Middle of the three parts of the small intestine

Small intestine is a long tube, with a small diameter (about 1 inch), extending from pyloric sphincter to the ileocecal valve and divided into duodenum, jejunum, and ileum.

The jejunum is located centrally in the abdomen, whereas the ileum lies mostly in the hypogastric region and pelvic cavity.

The jejunum makes up two-fifths of the total length of the small intestine and is about 0.9m in length. It starts at the duodenojejunal flexure and ends at the ileum.

The main function of the jejunum is absorption of important nutrients such as sugars, fatty acids, and amino acids.

It plays an important role for digestion as 40% of the whole small intestine is jejunum. Its functions include absorbing water and nutrients.

Absorption occurs at and is facilitated by numerous one to two cell layer thick fingerlike projection on the surface mucosa (villi) via active passive transport mechanisms. Absorption lipid breakdown product occurs mostly by passive diffusion protein-mediated processes.
Jejunum: Middle of the three parts of the small intestine

Digestion and absorption at infant age

Digestion and absorption at infant age
The complex process of digestion/absorption can be optimally effective only when the GI tract and accessory organs are totally develop and fully functioning.

Not only must the muscular tube (alimentary canal) with it a mucosal lining and endocrine cells be operating efficiently in conjunction with the nervous system, but the accessory organs (pancreas, liver, and gallbladder) with their important digestive secretions also must be physiologically mature.

The feeding of infants is based on primarily in degree of maturation of the GI tract and accessory organs.

Good examples of the emphasis on GI tract maturity are the care given to the fat in infant formula and the time and sequence of the introduction of various foods into the infant’s diet.

Only those fats possessing an ease used in commercial formulas and the introduction of solid food, beginning with baby cereal usually occurs no earlier than 4 months of age.

The infant pancreas, although structurally mature at term, is usable for several months to produce enzymes sufficient for effective digestion.

Pancreatic lipase, alpha-amylase and the proteolytic enzymes are in too short supply to accommodate digestion of a mixed diet. Digestion of fat is a real concern because there is a deficiency of bile salts from the liver as well as low lipase release from the pancreas.
Digestion and absorption at infant age

The Importance of Adequate Fiber Intake

The Importance of Adequate Fiber Intake
The importance of adequate intake of fiber to the improvement of health is demonstrated by some of the physiologic effects exerted by its various components. Particularly noteworthy are the hypoglycemic and hypolipidemic effect of soluble fiber. Slowing the absorption rate of carbohydrate can be very helpful to the diabetic in regulating blood glucose levels and lowering serum cholesterol levels presently appears to have significant benefit in the prevention of atherosclerosis.

Wheat 

Adequate fiber intake has been implicated in control of various gastrointestinal disorders, including diverticular disease, gallstones, irritable-bowel syndrome, inflammatory bowel disease, and constipation. It was suggested that fiber, especially wheat bran, is effective in the treatment of constipation; but evidence for the effectiveness of fiber in control of the other diseases seems equivocal. Nevertheless, populations with high fiber intakes have a lower incidence of these gastrointestinal disorders.

A generous fiber intake appears to be beneficial to some individual in their efforts at weight control. The bulk provided by fiber may have some satiety value, so that high fiber foods possibly reduce the hunger pangs associated with caloric restriction while simultaneously somewhat reducing nutrient utilization. The anti-toxic effect of fiber is a physiologic role often overlooked. Results of studies on experimental animals, particularly growing rats, have shows the protective effects of selected fiber supplements against a variety of toxic agents.
The Importance of Adequate Fiber Intake