B6.2 The Alimentary Canal Flashcards
What is ingestion?
Taking food and drink into the body (through the mouth)
What is digestion?
The breaking down of large food molecules into smaller water-soluble molecules using mechanical and chemical processes
What is absorption?
Movement of small food molecules through the wall of the intestine into the blood
What is assimilation?
The movement of digested food molecules into the cells of the body where they are used to produce other molecules or in respiration
What is egestion?
The passing out of food that has not been digested, as faces, through the anus
What is mechanical digestion?
The breakdown of food into smaller pieces without chemical change to the food molecules
What is chemical digestion?
The breakdown of large, insoluble molecules into small, soluble molecules
Identify the 8 main regions of the alimentary canal
Mouth Salivary glands Oesophagus Stomach Small intestine Large intestine Rectum Anus
Functions of the gall bladder
- Stores bile from the liver
- Bile is passed along the bile duct into the small intestine, where it neutralizes the stomach acid in the chyme
Functions of the pancreas
- Produces amylase protease and lipase (pepsin and trypsin)
- Secretes digestive enzymes in an alkaline fluid into the small intestine
Functions of the small intestine
- First section: Duodenum
- Second section: ileum
- Secretions from the gall bladder and pancreas enter the duodenum to complete the process of digestion
- Digested food molecules are absorbed in the ileum
Functions of the large intestine
- Water is absorbed from the remaining material
- Faces is stored in the rectum and removed through the anus
Function of the anus
- Faeces are egested through the sphincter
Define peristalsis
Contractions of the muscles in the walls of the alimentary canal.
- Fibre in the food keeps the bolus bulky
Function of the mouth
- Teeth and tongue break down food into smaller pieces
Functions of the salivary glands (List 3)
- Produce liquid saliva
- Moistens food –> easily swallowed
- Contains amylase –> breakdown of starch
Functions of the oesophagus
- Bolus (each lump of swallowed and chewed food) is moved from the mouth to the stomach –> by waves of muscle contraction called peristalsis
Functions of the stomach (List 5)
- Food is mechanically digested by churning
- Acid and protease enzymes are secreted to start protein digestion
- Provides optimum pH for protease to work
- Secretion of pepsin
- Kills bacteria in the food
Functions of the liver
- Cells in the liver make bile (emulsifies fats)
- Amino acids that are not used for making proteins are broken down to form urea –> passes to the kidneys for excretion
- Converts glucose to glycogen
In which organ does the digestion of proteins take place?
- Stomach
- Small intestine
Which structures secrete enzymes that digest proteins?
- Stomach
- Pancreas
Where does the digestion of carbohydrates take place?
- Mouth
- Small intestine