biology nutrition

• Digestion 


  is the process that breaks down large and complex pieces of food into smaller and simple pieces that can be dissolved for easy absorption
• Ingestion 


  Taking of substances into the body through the mouth
• Absorption 


  Movement of digested food molecules and ions through the wall of the intestine into blood
• Assimilation 


  movement of digested food molecules into the cells of the body where they are used becoming part of these cells
• egestion 


  passing out of food that has not been digested or absorbed as fasces through the anus
• Explain how digestion occurs

  Salivary gland secretes saliva

  Salova contains salivary amylase enzyme

  Salivary amylase breaks down starch into maltose
• Oesophagus muscle 


  Circular muscle

  Longitudinal muscle

  Both undergo peristalsis action

  This contraction of muscle will move food down
• Oesophagus 


  Food bolus is moved by peristalsis action caused by circular muscle and longitudinal muscle

  Circular muscle and longitudinal muscle perform antagonistic action

  Contraction of muscle will move food along the food along the alimentary canal
• Enzymes pepsin function 


  break down polypeptides into amino acids
• Hydrochloride acids function 


  kill bacteria present in food

  Provides acidic pH for optimum enzyme pepsin to function

  Stops the action of salivary amylase enzyme

  Coagulates milk protein
• Mucus 


  Mucus protects stomach wall from action of hydrochloride acid and enzymes
• Gastric gland 


  gastric gland ( tissue) in stomach secretes gastric juice containing hydrochloride acid, enzyme pepsin and mucus