While in the gallbladder, water is absorbed from the bile. This serves two functions: to neutralize the acidic secretions of bacteria in the mouth (the scourge of dentists everywhere), and, under certain circumstances, to neutralize the effect of stomach acid after vomiting. The other two functions are to start the digestion of starches by using salivary amylase (more about that later), and to raise the pH of the mouth. Saliva, from any of our three main salivary glands (parotid, sublingual, and submandibular), first and foremost provides lubrication for the chewed food, so that when it is swallowed, the spit and food combo (called a bolus) can slide easily along the esophagus. The mouth may be the start of it all, but without the salivary glands, it wouldn't be a very fun ride! Have you ever chewed dry crackers when your mouth was already dry? Even worse, have you ever swallowed dry crackers when you had a dry, scratchy sore throat? SCRAAAAAPE!! Luckily, that is not a very common experience due to the wonders of spit, or should I say, saliva. Thinking about the vinegar taste (an acid) in a pickle is enough to cause a lot of people to salivate, once again, to lower the pH! Placing food in your mouth will trigger receptors on the three of the cranial nerves (N VII, N IX, N X), but the mere thought of food can cause salivation. Secretion of saliva is controlled by both parasympathetic nerve pathways and conscious thought. Their accessory function merely implies that the food never passes through these organs. You couldn't survive, for instance, without a pancreas.
![running sheep anatomy running sheep anatomy](https://thumbs.dreamstime.com/b/running-woman-visible-anatomy-skeleton-39788491.jpg)
Some of you may take exception to having them called accessory, when their function seems so crucial. They need help, and that help comes from the accessory organs. These organs are all well and good, but they cannot function alone. Contraction at various points pinches the small intestine at different points, making it look a lot like a string of sausages-interesting, because the gastrointestinal tract of cows, pigs, sheep, and goats are still used today as a sausage casing! These segments, through repeated contractions, churn the food, allowing it to mix well with the various enzymes at work. In addition, the alternating contractions also help to mix the food in a process known as segmentation. The alternation of these contractions propels the food forward.
![running sheep anatomy running sheep anatomy](https://media1.giphy.com/media/3EiMpkHH4lKq4/200_s.gif)
Remember the two layers of muscle in the muscularis layer of every digestive organ? The longitudinal layer shortens the length of the organ, while the circular layer constricts the lumen, and thus pushes the food along the tract, rather like pushing a present through a Christmas stocking. Oh, sure! It's easy to say that the food travels along the gastrointestinal tract, but how does it move? Through a cool process known as peristalsis.