Digestive System GCSE

• What are Digestive enzymes needed for?

  Needed to break down big molecules that cannot pass through the walls of the digestive system.
• What is a property of all big molecules(Starch, proteins and fats)?


  They are insoluble.
• What breaks Starch down?


  Amylase
• What is starch broken down into?


  Maltose
• What breaks Maltose?


  Maltase
• What is maltose broken down into?

  Glucose
• What breaks protein down

  Protease
• What is protein broken down into?

  Amino acids
• What breaks lipids down?

  Lipase
• What are lipids are broken down into?

  Fatty acids and Glycerol.
• What is the function of Bile (HCl)?

  To neutralise the HCl (which is too acidic for the enzymes) in the stomach to have an optimum pH for enzymes in the small intestine.
• What is the function of Bile (Emulsification)?

  It increases their surfaces area for lipase to work on to which increases the rate of digestion.
• Where is bile produced?

  The liver
• Where is bile stored?

  The gallbladder
• Where is bile released?

  Into the small intestine.
• What does the pancreas produce?

  Protease, Amylase, Lipase enzymes and releases them into small intestine.
• What is peristalsis?


  The movement of food (bolus) through the gut.
• How does peristalsis occur?


  Circular muscles contract in order to stop food from getting clogged up.
• What is the function of the mouth?


  Salivary glands produce amylase in the saliva

  Teeth and tongue break food down mechanically.
• What is the function of the oesaphagus?


  Connects the mouth to the stomach.
• What is the function of the Stomach?

  1.Pummels food with muscular walls

  2.Produces protease enzyme pepsin

  3. It produces HCl
• Why is HCl produced in the stomach

  1.To kill bacteria

  2. To provide the right pH for protease enzymes in the stomach (pH 2 - acidic )
• What is the function of the small intestine?

  Produces protease, amylase and lipase

  Nutrients are absorbed out of the alimentary canal.
• What is the function of the large intestine?

  Where excess water is absorbed from food.
• What is the function of the anus?

  Where faeces (undigested food) are egested
• What is assimilation?


  The movement of digested food molecules into body cells where they're used
• What is an example of assimilation?

  Amino acids for cellular proteins

  Glucose for respiration
• How are villi adapted for maximum absorption?

  1.Large surface area - Microvilli

  2. High concentration gradient between blood and small intestine

  3. Constant supply of blood

  4.Short diffusion distance
• Trachea

  It is also known as windpipe, it filters the air we inhale and branches into the bronchi.
• Lungs

  The main organ of the respiratory system. These structures contain the bronchioles and alveoli.
• Bronchi

  It allow the passage of air from the trachea to the bronchioles in the lungs. There are two of them.
• Larynx

  Commonly called the voice box, this structure allows for vocalisation(speaking).
• Alveoli

  These are tiny sac like structures present in the lungs where the gaseous exchange takes place.
• Diaphragm

  This dome-shaped muscle located at the bottom of the lungs, allows breathing to occur.
• Bronchioles

  smallest branches off the bronchi, that deliver air to the alveoli.
• intercostal muscles

  muscles between the ribs that allow breathing to happen
• internal intercostal muscles

  The intercostal muscles on the inside that lowers the rib cage during expiration
• external intercostal muscles


  The intercostal muscles on the outside the raises the rib cage during inspiration
• Inspiration (inhaling)


  breathing in
• expiration (exhaling)


  Breathing out