Video Transcript
Which of the following is the
correct order of the different stages of digestion? (A) Gastric, buccal,
intestinal. (B) Intestinal, gastric,
buccal. (C) Buccal, intestinal,
gastric. Or (D) buccal, gastric,
intestinal.
This question asks us to order the
different stages of digestion, which is the process that breaks down large molecules
from food into smaller useful molecules that can be absorbed and transported to the
body cells that require them. Let’s briefly review how the food
we eat is digested in order to answer this question correctly.
Digestion begins in the mouth
immediately as food is placed into it. The word buccal refers to the mouth
itself. And this first stage of digestion
is called buccal digestion. Here, food is mechanically digested
by the teeth and tongue, physically separating food molecules to give them a larger
surface area. And carbohydrates begin to be
chemically digested by enzymes in saliva.
Next, food moves from the mouth
down the esophagus to the stomach. The word gastric refers to the
stomach. And gastric digestion takes place
here. The muscular walls of the stomach
mechanically digest food, while enzymes begin to chemically digest proteins in
food.
From the stomach, food moves into
the small intestine, where intestinal digestion occurs. This includes the chemical
digestion of carbohydrates, proteins, and lipids, and the subsequent absorption of
the smaller molecules that they are broken down into.
Now we have enough information to
answer this question correctly. Food moves from the mouth to the
stomach then to the small intestine. So the correct answer to our
question is (D) buccal, gastric, intestinal.
