消化和吸收(英文版).ppt

按一下以編輯母片標題樣式,按一下以編輯母片本文樣式,第二階層,第三階層,第四階層,第五階層,*,Main processes of mammalian nutrition,Ingestion,Digestion,Absorption,Assimilation,Egestion,Digestion,Absorption,Egestion,Next,Back,Main processes of mammalian nutrition,Ingestion,Digestion,Absorption,Assimilation,Egestion,Digestion,Absorption,Egestion,Next,Back,Ingestion,is the,intake,of food into the,alimentary canal,relevant organs:,teeth,relevant processes:,swallowing,peristalsis,Next,Back,Ingestion II,is the,intake,of food into the,alimentary canal,relevant organs:,teeth,relevant processes:,swallowing,peristalsis,Back,Next,incisor,canine,premolar,molar,Digestion,is the,breaking down,of food into molecules small enough to be absorbed into the body,relevant organs,mouth and,teeth,alimentary canal,stomach,duodenum,Back,Next,Absorption,is the,movement,of digested,soluble and simple molecules from the gut through the wall into the body,(,Contd,),relevant processes,diffusion,active transport,relevant structures,Back,Next,Assimilation,is the,uptake,&,utilisation,of absorbed food molecules by all body cells,fate of the absorbed food,glucose,energy production,amino acids,building up body materials,fats,energy reserve,roles of liver in assimilation,Back,Next,Egestion,is the,removal,of undigested and unwanted food materials from the alimentary canal,relevant structures,abnormal cases:,diarrhoea,constipation,Back,Next,Egestion,II,is the,removal,of undigested and unwanted food materials from the alimentary canal,relevant structures,abnormal cases:,diarrhoea,constipation,Next,Back,Teeth,structure of a tooth,enamel,dentine,pulp cavity,type,dentition,Next,Back,Enamel,Dentine,Pulp Cavity,Jaw Bone,Cement,Nerve&blood vessel,Crown,Neck,Root,Teeth II,structure of a tooth,enamel,dentine,pulp cavity,type,dentition,Crown,Neck,Root,Enamel,Dentine,Pulp Cavity,Jaw Bone,Cement,Nerve&blood vessel,Next,Back,Enamel,outermost,non-living,hardest layer,made up of,calcium phosphate,calcium fluoride,organic matter,Next,Back,Dentine,middle layer,hard,bone like(softer than enamel),Next,Back,Pulp Cavity,innermost layer,living cells,blood vessels and nerve,blood vessels,:oxygen and nutrient,nerves,:sensitive to stimuli,temperature,pressure,Next,Back,Type of Teeth,Next,Back,Dentition,dental formula of a human,type of teeth,on one side only,upper jaw,lower jaw,milk teeth:permanent teeth:,2120,2120,2123,2123,Next,Back,20,32,premolar,molar,canine,incisor,Tooth Decay,caused by the,chemical actions,of bacteria in plaque,plaque is a,sticky,invisible film,on the teeth surface,bacteria turns,sugars,into,acids,acids,dissolve,the enamel and dentine,Next,Back,Tooth Decay,caused by the,chemical actions,of bacteria in plaque,plaque is a,sticky,invisible film,on the teeth surface,bacteria turns,sugars,into,acids,acids,dissolve,the enamel and dentine,irritation on the,nerve,cause,toothache,Next,Back,How to prevent tooth decay,good,brushing habits,using appropriate,cleaning materials,avoiding,sugary,food,having a,balanced diet,having regular,dental check-up,Next,Back,Alimentary Canal,a,tube,from mouth to anus,is,modified,into different structures,digestive system=,alimentary canal,+,associated,alimentary canal,associated glands,Next,Back,Alimentary Canal,a,tube,from mouth to anus,is,modified,into different structures,digestive system=,alimentary canal,+,associated glands,sequence,of the structures,oesophagus,stomach,duodenum,ileum,caecum,appendix,colon,rectum,anus,Salivary gland,Gastric gland,Pancreas,Liver,Intestinal gland,Next,Back,alimentary canal,associated glands,Swallowing,tongue raises pushing the,bolus,to the back,bolus pushes the,soft palate,upwards,epiglottis,lowers and covers the trachea,bolus enters the,oesophagus,Next,Back,Peristalsis,food is moved along the canal by,rhythmic contraction,and,relaxation,of two muscles,circular muscle,longitudinal muscle,demonstration,Peristalsis,Next,Back,Oesophagus,Digestion II,only small molecules can pass through the wall of intestine,food are usually composed of,large,molecules,food should be digested before absorption,physical methods,chemical methods,Next,Back,Physical Digestion,Teeth,Stomach,Bile salt,by churning,by emulsifying action in duodenum,by,cutting,chewing,grinding,biting,tearing,Next,Back,Chemical Digestion,involved the change of the chemical structures of food,e.g.,this involves,digestive enzymes,no digestion on:,water,glucose,simple sugars,minerals,vitamins,Starch,maltose,maltose,maltose,maltose,Next,Back,amylase,Mouth,saliva is a digestive juice consisting of,amylase,mucus,water,it is slightly alkaline,Next,Back,Stomach,cardiac sphincter,action of,proteases,action of hydrochloric acid,provide acidic medium for proteases,pyloric sphincter,Next,Back,protease,Duodenum,pancreatic juice,amylase,proteases,lipases,bile,colour,composition,no enzymatic property,intestinal juice,carbohydrases,proteases,Next,Back,Caecum,Colon&Rectum,no enzyme secretion in,omnivores,and,carnivores,specific function in,herbivores,micro-organisms,cellulase,weakness,Next,Back,Absorption II,take place in ileum,starts at stomach/duodenum,villus,Next,Back,Villus,finger like projections,increase S.A./V,one cell thick,many blood vessels,central lacteal,villus,lacteal,Blood vessels,epithelium,Next,Back,Transport of absorbed food,lumen,Back,epithelium,blood capillaries,hepatic portal vein,liver,hepatic vein,vena cava,heart(general circulation),Next,Water soluble food,Fat soluble food,lumen,epithelium,lacteal,Lymph vessel,vena cava,heart(general circulation),Assimilation II,fate of absorbed food substances,glucose,amino acids,fats,roles of liver,Next,Back,Fate of glucose,for releasing energy,excess glucose will be stored as,glycogen,fats,storage site,liver,muscle,Next,Back,Fate of amino acids,for making new cells and tissues,excess amino acids will be,deaminated,product:urea,site of excretion:,kidney,Next,Back,Fate of fats,for formation of cell membranes,excess fats will be stored,fats,storage site,adipose tissue,Next,Back,Roles of liver,regulating blood glucose level,storing glycogen,storing iron and vitamins,breaking down excess amino acids,Next,Back,Diarrhoea,Causes:,(1)bacterial infection,(2)eating poisonous substances,Consequences:,(1)quick movement of intestine,(2)food passes along the canal quickly,(3)less water absorbed,(4)watery,faeces,produced,Next,Back,Constipation,Causes:,eating too less dietary,fibres,eating too less fresh fruit,Consequences:,(1)slow movement of intestine,(2)food passes along the canal slowly,(3)much water absorbed,(4)hard,dried,faeces,produced,Next,Back,End of the Chapter,By Nicholas,Lai,(PLKWCC),Glossary,Active transport:movement of molecules against concentration gradient with the utilizing of energy.,Amylase:an enzyme that convert starch to maltose.,Carbohydrases,:enzymes digest carbohydrates into simpler molecules.,Carnivores:organisms feed on animals only,Diffusion:movement of molecules from a region of high concentration to a region of low concentration,Herbivores:organisms feed on plants only,Lipases:enzymes digest fat/oil into simpler molecules,Glossary,Mucus:a sticky substance secreted by epithelial cells of the gut,Omnivores:organisms feed on animals and plants,Proteases:enzymes digest protein into simpler molecules,