The mucosa of the majority of the digestive tract contains simple columnar epithelium, while the esophagus and the anus have stratified squamous epithelium. Why is this the case? What purpose does each type of epithelium serve in the digestive tract?
What will be an ideal response?
Columnar epithelium is primarily responsible for secreting and absorbing materials across its membranes whereas
stratified squamous epithelium is primarily present for protection of the tissues beneath it. Since the stomach and
intestines secrete enzymes and other chemicals important for digesting food and since they absorb nutrients and
water, they have simple columnar epithelium. Since the esophagus is carrying undigested food from the mouth to
the stomach and not absorbing anything, it makes sense that it would have stratified squamous epithelium to
protect the tissues beneath it from the ingested food particles. Since the anus is primarily a passageway for feces to
leave the body and it would not be beneficial for the feces to come into contact with the tissue beneath it, stratified
squamous epithelium also makes sense in the anus.
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