Digestive System
Ingestion
I for in
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Taking food into the body
Mouth
Teeth, lips, and tongue
Both physical and chemical digestion
Salivary Gland (唾液腺)
Make saliva - water, mucus, amylase
chemical digestion
Oesophagus (食管)
Tube connecting mouth to stomach
Peristalsis of muscles to move the food down: physical digestion
Has a sphincter muscle(括约肌) where it connects to the stomach
Trachea(气管): airway that connects mouth to lungs
Digestion
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Breaking large insoluble molecules into small soluble molecules
Physical Digestion
Biting, chewing grinding, cutting, emulsifying
Chemical Digestion
Enzymes, acids
Stomach
Strong, muscular walls for mixing the food with enzymes and mucus and storing food for a few hours
sphincter muscles both at the top and bottom of stomach; relax to let food through
Stomach cells produce: Mucus, Enzymes: protease, Hydrochloric acid: low pH to kill bacteria
Both physical and chemical digestion
Small Intestine - Duodenum
Next stop from stomach
Pancreatic juice(胰液) and bile(胆汁) are released by different organs into the duodenum
Contains enzymes:,
alkaline to neutralise
Both physical and chemical digestion
Liver and Gall Bladder
Liver produces bile, and gall bladder stores bile
bile is released into duodenum through a tube called bile duct
bile neutralizes the acidic mixture from stomach
also helps with physical digestion
Pancreas
Pancreas makes enzymes - lipase, protease, amylase that are released into duodenum
chemical digestion
Absorption
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Movement of small soluble molecules and mineral ions from small intestines into the blood
Through Diffusion, then Active Transport
Small Intestine - ileum
between duodenum and large intestine
Absorption of broken-down nutrients and water into the blood
Assimilation
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Nutrients are absorbed by individual cells and become part of the body
Egestion
E for exit
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Fiber and other undigested, unabsorbed materials remain in the intestines and are egested
Large Intestine - Colon and Rectum
Colon absorbs water and minerals (less than ileum)
Rectum stores undigested food as feces
Egestion happens through the anus
Alimentary Canal
A pathway or a track tat food passes through
contains muscles that can do peristalsis
Secretes mucus(粘液) form goblet cells
Accessory Organs
Food doesn’t pass through them
they make essential digestive enzymes