• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

The structure and function of the ileum in relation to absorption and digestion.

Extracts from this document...

Introduction

SUMUDU LANKATILAKE 17-FEB-03 THE STRUCTURE AND FUNCTION OF THE ILEUM IN RELATION TO ABSORPTION AND DIGESTION The ileum is the second part of the small intestine located after the duodenum. It has a vital function in digestion and has a suitable structure to accommodate for its functions. The ileum is 6 meters long and the main site foe the absorption of the soluble products of digestion. The ileum is efficient at this for the following reasons: * It is fairly long and presents a large absorbing suface to the digested food. * Its internal surface is greatly increased by circular folds bearing thousands of projections called villi. These villi are about 0.56mm long and may be finger like or flattened in shape. * The lining epithelium is very thin and the fluids can pass rapidly through it. ...read more.

Middle

The hepatic potal vein and the umphatic system run through the sub mucosa. The sub mucosa and mucosa is separated by a layer called muscularis mucosae. The following two layers are the muscle layers and beneath all the layers is the serosa. The main function of the small intestine is absorption although some digestion does occur. The final stages of digestion of carbohydrates, lipids and proteins occur here, while absorption occurs. Carbohydrates in the form of monosaccharides and amino acids are absorbed partly by diffusion and partly my active transport. Soon after a meal there will be a higher concentration of monosaccharides and amino acids in the ileum, and so a concentration gradient will exist and diffusion of these molecules will occur across the mucosal epithelium in the blood capillaries. ...read more.

Conclusion

For digestion that occurs in the ileum intestinal juice is secreted by the small intestine and the digestion occurs in the small intestine itself. The intestinal juice contains maltase, sucrase, lactase, enterokinase, aminopeptidase, lipase, nucleotidase, mucus. Each are an enzyme which have a specific molecule to act on. Maltase acts on maltose and converts it into glucose. Sucrase acts on sucrose and breaks it down into glucose and fructose. Lactase acts on lactose and breaks it down into glucose and galactose. Enterokinase acts on trypsinogen and breaks it down to trypsin. Aminopeptidase acts on peptides and converts it into amino acids. Lipase acts on fats and converts it into fatty acids and monoglycerides. Nucleotidase breaks down nucleotides and mucus is also secretd for the lubrication of the food mass. The product molecules are all easier to absorb than their precursor molecules. The ileum of the small intestine eventually leads into the large intestine for further absorption. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Molecules & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

4 star(s)

Much of the relevant information is included in this essay but its overall structure needs some reworking. A clear distinction between digestion and absorption would make it easier to follow. An alternative approach is to deal with each of the four layers of the ileum wall in turn, relating their structure and function.
Finally, the different cell types of the intestinal epithelium together with their functions was not covered in enough detail. Paneth cells, goblet cells, absorptive cells (enterocytes) deserve mention at A' Level.
This is a good example of an essay which needs careful planning before putting pen to paper (or fingers to keyboard.)

Marked by teacher Ross Robertson 01/03/2013

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Molecules & Cells essays

  1. Marked by a teacher

    Cellular Structure and Function

    5 star(s)

    Besides the digestive system, this type of epithelium is also present in the eyes, ears, respiratory system, and female reproductive organs. Below drawing shows simple columnar epithelium from the stomach. They are longer than they are wide and have the characteristic of their nucleus being near the base of the cell.

  2. Qualitative tests for carbohydrates

    Furfural further reacts with orcinol and the iron ion present in the test reagent to produce a bluish green product which may precipitate. So a positive result gives a bluish green product. (see fig.5)(www.harpercollege.edu - Nov. 2007) (fig. 5 Bial's test positive result)

  1. The Effect of Concentration on Pectinase Using Apple

    the rate at which the juice could be extracted began to decrease. This is a general graph showing the effect of enzyme concentration on the rate of the reaction: This graph shows that with ample substrate molecules, the enzyme concentration is directly proportional to the rate of reaction.

  2. Describe the structure of the xylem and the phloem.

    The lumen size of the xylem is also important, and it is by no mistake that the xylem has no living contents. The fact that there are no living organelles means a number of things. It increases the size of the lumen, allowing more water to be moved in vast quantities.

  1. An experiment to find of the isotonic point of root vegetables cells in contents ...

    I also predict that as the cell becomes flaccid in the isotonic solution, the pressure potential exerted will become zero and due to slight fluctuations in pressure potential the length may be affected. This is why I predict that at the isotonic point the mass will be unaffected but the

  2. Affect of sucrose concentration on the rate of respiration.

    This makes the reaction occur faster because the weakened bonds are easier to break. The enzyme is usually very large compared to the reacting substrate. Enzymes have folds and creases and the reactant molecules fit into a definite location in these folds and creases.

  1. An Investigation Into The Digestion Of Milk By Trypsin.

    At this pH, the enzyme amylase, from your saliva cannot work at all. Inside most cells the enzymes work best at a pH of 7, as it is neutral. The pH or temperature at which this enzyme works is called its optimum pH or temperature.

  2. An Experiment to investigate the factors that affect the Power Output of a solar ...

    A solar cell is an electrical power supply. It follows the same concept as a battery. These cells are essentially converters that use one form of energy (light), and convert it into another form (electricity). However, when it does not get the light form of energy, if for example it is completely dark, the conversion process slows down and eventually stops.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work