人體消化系統 Digestive Syetem

we can answer the question in mainly two parts: mechanical digestion and chemical digestion

For mechanical (physical) disgestion, the peristalsis of both small and large intestine help break down food into smaller pieces, and hence increasing their suface area for the action of digestive enzymes.

For chemical digestion, duodenum receives pancreatic juice from the pancreas,in which the pancreatic juice contains pancreatic amylase (catalyse the breakdown of starch into maltose), lipase (catalyse the breakdown of lipids into fatty acids and glycerol) and proteases( catalyse the breakdown of proteins in peptide chains OR peptide chains into amino acid).

Secondly,villi are present in our intestine and there are brush btorder enzymes at the epithelium of the villi, which also help the breakdown of food as stated above.

You may also include that small intestine receives bile produced from liver (temporarily stored in gall bladder), that bile pigments emulsify lipids into tiny oil droplets, which increase the surface area of lipids for the action of lipase. Hence, this FACILITATES chemical digestion. (** it only facilitates chemical digestion but itself is NOT a chemical digestion)

小腸的主要功能的消化食物, 將食物變成可以吸收的養份, 如果小腸出了問題, 食物便無法有效地消化成有用的養份, 當事人會出現營養不良. 大腸是人體主要處理身體廢物的器官, 人體未能消化的, 沒有用的, 有毒的物質都會在大腸中經過脫水及重整的過程然後掛出體外, 如果大腸出了問題, 我們便無有效地處理廢物並將之排出體外, 有毒廢物長期留在體內會令身體出現很大的健康問題.