Absorption, Biology


The monosaccharides, amino acids and other products of digestion must be passed on to other tissues to be useful for the organism. The process by which the digested material from the alimentary canal enters the blood stream is known as absorption. In intracellular digestion the same cells are concerned with digestion and absorption but in higher multicellular animals there are usually separate tissues and areas of gut for enzyme production, digestion and absorption. In this section we will mainly be concerned with absorption of amino acids, sugars and fats released during extracellular digestion in vertebrates. In all vertebrates most of the absorption is localised in the intestine.

As you already know the wall of the vertebrate intestine is folded and ridged to increase the absorptive surface. These ridges or folds are covered by a velvet like pile of minute absorptive villi. These are highly specialised absorptive organs with a core containing a network of capillaries derived from blood vessels in the gut wall. Each villus also contains a central lymph capillary known as lacteal which begins blindly at the tip of the villus and drains into the main lymph channels of the gut wall. Lipids pass mainly into the lacteals while sugars and amino acids are absorbed directly by the blood capillaries. The villi and intestinal folds contain smooth muscles that contract to bring the villi in contact with the food in the intestine; and also maintaining the circulation in lacteals, lymphatics and small blood vessels.


Figure: Lining of mammalian small intestine a) Villus covered with digestive epithelium which consists of absorptive cell and occasional goblet cells. b)  An absorptive cell. The apical surface bears a brush border of microvilli.

Posted Date: 1/15/2013 5:39:19 AM | Location : United States

Related Discussions:- Absorption, Assignment Help, Ask Question on Absorption, Get Answer, Expert's Help, Absorption Discussions

Write discussion on Absorption
Your posts are moderated
Related Questions
Your methods so far have given some success! You now want to look at many different tissues in several individuals, some of whom have the mutation, some who are controls. How can y

V AGIN A - Median, elastic, muscular tube 7.5 cm long. Open into vestibule by vaginal orffice. The lining forms vaginal rugae. Space between vaginal wall & cervix is forn

How does chewing food help to speed up digestion? Chewing reduces food to portions small sufficient to be swallowed and enhances the surface area of the food for digestive enzy

Equipment and Supplies: Nurses who are aware of location of equipment and supplies do give accurate delivery of patient care without delay and wastage of  time and energy for

Ecological isolation is based on the fact that population shows preference to one habitat over the other. This extensive forests become barriers to the dispersal of organims living

What is the difference between octopuses and mussels regarding their circulatory systems? How does that difference influence the mobility of these animals? Cephalopod molluscs,

Shifting cultivation - Degradation of Ecosystem This method of cultivation is practised all over the globe, but is more prevalent in the tropical countries. In this practice a

Which of the following statements is most acceptable from an evolutionary point of view? (a) Apes and humans have evolved from a common ancestor. (b) Humans have evol

Describe the filaments in the muscle fiber A healthy skeletal muscle fiber is isolated and has no external forces on it. It has normal intracellular levels of ATP and is bathed

Cheese Production Cheese production involves the conversion of the milk protein, k-casein to paracasein by a defined, limited hydrolysis, catalysed by chymosin (rennin). In the