Lipid Absorption

The rate of gastric emptying is regulated to deliver packets of fat into the duodenum that may be easily digested and assimilated without overloading. The avoidance of duodenal overload is dependent on the efficacy of the neural and hormonal feedback mechanisms regulating gastric emptying and intestinal transit, the ileal brake.

The absorption of fat is a different process from that of carbohydrate and protein by virtue of the insolubility of the molecules of lipid in water (Figure 6). The products of lipase digestion, fatty acids and monoacylglycerols, are insoluble and so cannot diffuse through the chyme to reach the enter-ocyte membrane. The role of micelles produced by the action of bile salts is carriage of the lipid molecules to the enterocyte luminal membrane, where the fatty acids and monoacylglycerols diffuse from the micelle through the lipid component of the membrane to enter the enterocyte cytoplasm.

On this basis, the process of transport has always been assumed to be passive diffusion. Recently, it has been demonstrated that some carrier-dependent mechanisms are implicated. The observation that

Amino

Na+ acid Secondary active transport

Primary active transport

Primary active transport

Amino acid

Amino acid

Breaking Bulimia

Breaking Bulimia

We have all been there: turning to the refrigerator if feeling lonely or bored or indulging in seconds or thirds if strained. But if you suffer from bulimia, the from time to time urge to overeat is more like an obsession.

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