The Human Digestive System (WJEC GCSE Biology)

Revision Note

Emma

Author

Emma

Last updated

The Human Digestive System

  • The human digestive system is made up of the organs that form the alimentary canal and accessory organs
    • The alimentary canal is the channel or passage through which food flows through the body, starting at the mouth and ending at the anus. Digestion occurs within the alimentary canal
    • Accessory organs produce substances that are needed for digestion to occur (such as enzymes and bile) but food does not pass directly through these organs

The structure of the human digestive system diagram

The human digestive systemThe human digestive system includes the organs that form the alimentary canal, and accessory organs that aid the process of digestion

The roles of the organs of the digestive system table

Structure Function
Mouth

The mouth is where mechanical digestion takes place

Teeth chew food to break it into smaller pieces and increase its surface area to volume ratio

Carbohydrase (amylase) enzymes in saliva start breaking down starch

The food is shaped into a ball by the tongue and lubricated with saliva so it can be swallowed easily

Stomach

Food is mechanically digested by churning actions while protease enzymes start to chemically digest proteins 

Hydrochloric acid is present to kill bacteria in food and provide the optimum pH for protease enzymes to work

Pancreas

Produces all three types of digestive enzymes: carbohydrases, proteases and lipases

Secretes enzymes into the small intestine for digestion

Small intestine

Food coming out of the stomach finishes being digested by enzymes produced here and also secreted from the pancreas

Absorption of digested food molecules takes place. The small intestine is long and lined with villi to increase the surface area over which absorption can take place

Large intestine

Water is absorbed from the remaining waste material to produce faeces

Faeces is stored in the rectum and removed through the anus

Liver Produces and secretes bile to emulsify fats

You've read 0 of your 10 free revision notes

Unlock more, it's free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

Emma

Author: Emma

Expertise: Biology

Prior to working at SME, Emma was a Biology teacher for 5 years. During those years she taught three different GCSE exam boards and two A-Level exam boards, gaining a wide range of teaching expertise in the subject. Emma particularly enjoys learning about ecology and conservation. Emma is passionate about making her students achieve the highest possible grades in their exams by creating amazing revision resources!