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

The pathway of food molecules through the alimentary canal and the process of their digestion

Extracts from this document...


The pathway of food molecules through the alimentary canal and the process of their digestion The function of the digestive system is to break down large molecules in food, such as protein and starch, into monomers that can easily be absorbed into the body and with a balanced diet it does its job efficiently. The alimentary canal is a long coiled tube that runs through the body from the mouth to the anus. It consists of associated glands, the salivary glands, the liver and the pancreas. This muscular tube is organised into several distinct regions. The overall process of nutrition can be divided into several stages. Ingestion is taking in food. Humans put food into the mouth where it is chewed. Swallowing takes it down through the oesophagus and into the stomach. Mechanical breakdown is how food is broken down into smaller pieces by chewing in the mouth and the churning action of the stomach. Digestion is the complex breakdown of foods such as carbohydrates, lipids and proteins into simpler molecules. ...read more.


Digesting protein is one of the main functions of the stomach. Pepsin breaks peptide bonds in the middles of the protein chain, which turns protein molecules into polypeptides. This process is complete when exopeptidase enzymes remove amino acids from the ends of the polypeptides. Mucous cells secrete the mucous that protects the stomach lining from digestive action of its own secretion. Food then moves from the stomach to the small intestine in the form of chyme. The small intestine is the major site of digestion and consists of the duodenum and the ileum. Enzymes and secretions flow into the duodenum from the pancreas and the liver. Pancreatic juice enters the duodenum via the pancreatic duct, this is an alkali solution and neutralises the strong stomach acid. This fluid contains several enzymes. Trypsin is an endopeptide enzyme that breaks down proteins into polypeptides. Carboxypeptidase is a polypeptide digesting enzyme that converts these into smaller peptides and amino acids. Pancreatic amylase completes the breakdown of starch to maltase. ...read more.


Each structure relates to the one before and the one after and a balanced diet is necessary for this efficiency. The mouth is a hard cavity containing teeth and the tongue, which efficiently breaks down food into a suitable state to travel through the oesophagus. The oesophagus, which is a rigid tube with a smooth surface, pushes the food to the stomach. The stomach, a muscular sac, aids in the mechanical breakdown of food. Cells in the gastric pits of the stomach aid in the chemical breakdown of food. This result is liquidation of the food in preparation for the small intestine. The small intestine is the longest section of the alimentary canal and here the most part of chemical digestion and absorption takes place. This moves the food to the large intestine. These are the final stages of digestion where the food is being prepared for egestion. The last minerals and water are taken here in this tube which is about 1.5 meters long. Finally the food is passed though the rectum and the anus, which are concerned with the compaction of faeces and the act of defecation. ?? ?? ?? ?? ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Food Technology section.

Found what you're looking for?

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

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 GCSE Food Technology essays

  1. Mechanisms of Digestion

    The main enzymes used in the digestive system are: * Amylase- This enzyme is used to digest starches and Carbohydrates, it turns them into a substance called Maltose. * Pepsin- This enzyme helps digest proteins, and turns them into amino acids.

  2. Describing the Nature of the FAO Report "The State of Food Insecurity in the ...

    of the MDG's but also as a crucial condition for reaching the other MDGs. As a consequence of thorough scientific research the report revealed proof to the statement that hunger and malnutrition are the main reasons why the targets of the other MDGs have not been successfully achieved.

  1. What are the main functions in digestion of thea) ...

    as alcohol, paracetomol and other chemicals into safer form, Storage of vitamins A,D,E and K, Storage of glycogen, which can be broken down into glucose and used for energy by the body when required, The large intestine is also known as the colon.

  2. Globalisation and regulation of food risks. A theoretical overview.

    Food for human consumption is mostly bought at shops and markets, (increasingly supermarkets) and the daily menu is mostly based on standard products. The continuing separation between food producers and food consumers is escalating, leading to a situation where large amounts of cheap foods are available but where producers and consumers of food are also separated in time and space.

  1. Research question: Do the Chinese fast food chains in Hong Kong behave in oligopoly ...

    I have distributed 100 questionnaires to the consumers. I chose the interviewers randomly, as I discovered that their impressions could be very different if I interview them in front of a fast food outlet. Therefore, the places that I interviewed were not very close to any Chinese fast food outlets, so as to make survey become more objective and fair.

  2. There has become an increasing demand for single portion food products - I will ...

    This would be very unsuitable, as I do not want/need this amount. It also requires investment. * Batch Production: - This is a method which produces a specific product about 50- 1000 times, the machinery is then cleaned are re-programmed to produce another product; An example of this is a bakery.

  1. Structure and function of the digestive system.

    Saliva consists of 99.5% water with 0.5% dissolved substances including mineral salts, salivary amylase, mucin and lysoeme, which is an enzyme that kills bacteria. Salivary amylase, which is a proteins splitting enzyme, begins the process of chemical breakdown turning starch into maltase.

  2. Investigation on enzymes.

    This is because doubling the bile will halve the surface area of the fat, which will halve the time, taken for the lipase to break it down. Monitoring the experiment will prove quite difficult because there is no way of accurately telling when the fat has been completely broken down.

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