regional specialisation of the mammalian gut

• what is meant by a buccal cavity


  mouth
• what happens in the buccal cavity


  mechanical digestion which increases the surface area of the food molecules for chemical digestion
• what three molcules does saliva contain


  amylase , bicarbonate ions and mucus
• what enzyme breaks down starch into maltose


  amylase
• what is the function of bicarbonate ions


  this creates the optimum PH for amylase to work
• what is the function of mucus in the salavia


  lubricate food
• what is the role of the oesophagus


  carries food from mouth to stomach
• what is the function of the sphincter muscles in the stomach


  these contract to keep food in the stomach
• how long can food remain in the stomach


  several hours
• what happens in the stomach for digestion


  the walls contract rhythmically to churn the food with gastric juice
• where is gastric juice secreted in the stomach


  in the stomach wall where it is secreted from gastric glands in the mucosa
• what are the three components of gastric juice


  hydrochloric acid , pepsin and mucus
• what is the function of mucus in the gastric juice


  to protect the stomach lining from the strong acid
• where in the mucosa is mucus secreted


  in the goblet cells that line the mucosa
• what is the function of HCl in gastric juice


  this creates optimum environment for enzymes to kill bacteria
• what ph will HCL turn the gastric juice to help kill the bacteria


  ph2
• what glands secrete an inactive form of pepsin called pepsinogen


  gastric glands
• what converts pepsinogen into pepsin


  hydrochloric acid
• what cells are located in gastric glands to secrete pepsinogen


  chief cells
• what secretes hydrochloric acid


  oxynitic cells
• where is the cardiac sphincter


  top of stomach

  
• where is the pyloric sphincter


  bottom of stomach

  
• what are the three layers in the lining of the stomach , in the order from inward out

  sub-mucosa , mucosa and serosa