Question

How is carbohydrates digested and absorbed after eating a peanut and jelly sandwich on whole wheat including the constituents representing carbohydrates and how and where they are digested and absorbed and how and where carbohydrates are utilized or stored in the body. Include the chemical, hormonal, and enzyme changes that impact this meal.

Answer 1

Digestion of carbohydrates starts in the mouth itself, here both mechanical (chewing of food) and chemical digestion takes place(salivary amylase) which breaks the complex carbohydrates into, polysaccharide,dextrin,sucrose, lactose maltose,

After this these molecules are passed down to stomach as bolus,

In stomach no any digestion of carb. Takes place because of acidic environment.

After stomach, food is called chyme, which enters upper S.I. and here, pancreatic juice containing amylase, is useful for digestion of molecules further. Which converts all poly or oligosaccharides to disaccharides and monosaccharides, along with this, from the villi of intestine, sacchatidases are secreated which further convert them into monosaccharides.

And after formation of these monosaccharides, they are absorbed from intestinal cells and transferred to blood,

Fructose (facilitated diffusion) glucose & galactose (active diffusion)

After entering blood first organ they reach is, liver, here energy formation or storage of glucose as glycogen, or supply of glucose to whole body takes place depending on requirement.

Above is mainly enzymatic mechanism, hormonal mechanism involves various hormones like,

Cortisol, insulin, glucagon, in this

Insulin promotes formation of glycogen & glycolysis & link reaction

While glucagon promotes, all other catabolic pathways related to glucose