1 Mouth---Food is placed in mouth using cutlery/hands.
The food is mechanically broken down by the teeth It is called mastication.
Whilst food is chewed,it is mixed with saliva.
2 Salivary glands---produce saliva containing salivary amylase which catalyse the hydrolysis of starch to maltose.
3 Oesophagus(esophagus)---Food moves down the oesophagus by peristalsis.Mucus procuced by goblet cells helps the movement of the food.
4 Stomach---the stomach lining produces gastric juice from gastric glands containing enzymes dealing with protein digestion.
5 Small intestine---3 major parts
[Digestion]
Duodenum---receives 4 secretions
1)Bile--produced by gall bladder and stored in liver.It contains bile salts which emulsify lipids.
2)Pancreatic juice---produced by pancreas.
The pancreas is made of 2 sorts of glandular tissue.
Endocrine glands--produce hormones like insulin
Exocrine glands---produce pancreatic juice containing various enzymes including pancreatic amylase.
3) Fluid from Brunner's gland---contains alkaline fluid(keep the pH above 7) and mucus
4) Intestinal juice---produced by the walls of duodenum,jejunum and ileum by paneth cells.The mucus in the juice softens foods,stops foods damaging the intestinal wall and stops enzymes digesting the wall.
Jejunum and ileum---they receive 2 secretions
1)Intestinal juice(同上）
2）Mucus from goblet cells in the epithelium.
In addition,carbohydrates(disaccharides) digested by enzymes sitting on the epithelial cells
[Absorption]
Ileum---Water soluble substances enter the blood capillaries by diffusion and active transport.Fat soluble substances (like fatty acids,glycerols,vitamin A ,D,E )pass into the lacteal then into the lymphatic system and finally into the blood system.
6 Large intestine---4 parts
1) Caecum---receives material from small intestine.together with the colon contains bacteria( Escherichia coli) metabolise the waste material or roughage.
2) Appendix---no digestive function.It deals with gut infection
3) Colon---absorbs water and vitamins.It contains bacteria that break down roughage.
4) Rectum---absorbs water and pellets the waste stored in the rectum and released it via the anus as faeces.
7 Anus---defaecation
（顺序不完全一样）