How your digestive System Works  1 of 4

Your digestive system gears up

A fresh-baked apple pie is browning in the oven. Just the sight and smell of it — and the anticipation of eating it — are enough to make you start salivating and producing stomach acids. So even before you take a bite, your digestive system has swung into action.

After the first steaming morsel enters your mouth, the many organs of your digestive tract kick into high gear. Here's a look at how your digestive system works, from top to bottom.

Mouth and salivary glands

After you take your first bite of pie, your salivary glands produce enough digestive juices (saliva) to begin breaking it down chemically. Besides the salivary glands in the lining of your mouth, you have three pairs of larger salivary glands — the parotid glands, sublingual glands and the submandibular glands. Together they produce 1 to 3 pints of saliva a day.

Not all of the work is chemical, though. As you savor the sweet apple tang, your teeth work to grind the pie while your tongue mixes it with saliva. This combination transforms it into a soft, moist, rounded mass (bolus) suitable for swallowing.