ANS102 Lecture Notes - Lecture 10: Gastrointestinal Tract, Salivary Gland, Serous Membrane
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Digestion)&)Nutrients)!
• An#animal’s#diet#must#supply#chemical)energy,#organic)molecules,#and#essential)nutrients##
• An#animals#diet#provides#chemical#energy,#which#is#converted#into#ATP#and#powers)processes#in#the#body#
• Animals#need#a#source#of#organic#carbon#and#organic#nitrogen#in#order#to#construct#organic#molecules#
• Essential)nutrients)are#required#by#cells#and#must#be#obtained#from#dietary#sources:#
– Essential#amino#acids#
– Essential#fatty#acids#
– Vitamins#
– Minerals#
• Undernourishment#is#the#result#of#a#diet#that#consistently#supplies#less#chemical#energy#than#the#body#
requires#
• Malnourishment#is#the#long?term#absence#from#the#diet#of#one#or#more#essential#nutrients#
• The#main#stages#of#food#processing#are#ingestion,#digestion,#absorption,#and#elimination)#
• Ingestion)is#the#act#of#eating,#animals#can#be#grouped#method#of#ingestion:#
– Suspension#feeders##
– Substrate#feeders##
– Fluid#feeders##
– Bulk#feeders#
• Digestion)is#the#process#of#breaking#food#down#into#molecules#small#enough#to#absorb,!In#chemical#
digestion,#the#process#of#enzymatic)hydrolysis)splits#bonds#in#molecules#with#the#addition#of#water#
• Abortion)is#uptake#of#nutrients#by#body#cells)
• Elimination)is#the#passage#of#undigested#material#out#of#the#digestive#compartment#
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Digestive)system))
• Most#animals#process#food#in#specialised#compartments#
• These#compartments#reduce#the#risk#of#an#animal#digesting#its#own#cells#and#tissues#
• In)intracellular)digestion,#food#particles#are)engulfed#by#endocytosis#and#digested#within#food#vacuoles)
• Extracellular)digestion)is#the#breakdown#of#food#particles#outside#of#cells#
• It#occurs#in#compartments#that#are#continuous#with#the#outside#of#the#animal’s#body#
• Organs#specialised#for#sequential#stages#of#food#processing#form#the#mammalian#digestive#system##
• The#mammalian#digestive#system#consists#of#an#alimentary#canal#and#accessory#glands#that#secrete#
digestive#juices#through#ducts#?#mammalian#accessory#glands#are#the#salivary#glands,#the#pancreas,#the#
liver,#and#the#gallbladder#
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Anatomy)of)the)digestive)system))
• Four#major#layers#of#gastrointestinal#tract##
– Mucosa#
– Submucosa#
– Muscularis#
– Serosa#
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