Danielle has a PhD in Natural Resource Sciences and a MSc in Biological Sciences
Mastication simply means chewing or grinding up food with your teeth, something you do every day. When you take a bite of food, it gets positioned between your teeth by the cheek and tongue. The purpose of chewing your food, in addition to making sure you don't choke, is to increase the surface area of your food so that your salivary enzymes can start to break it down.
Chewing is actually the first step of digestion. For example, as you chew on a cracker, it will gradually become softer, mushier, and warmer as your saliva begins to break down the carbohydrates. Once you swallow this new blob of food, called a bolus, it enters your esophagus and heads towards the stomach. Chewing is a critical step of digestion, but is often overlooked when reviewing the process.
In cases where a human or animal cannot chew for themselves, a process called premastication may take place. In this situation, an adult will chew the food for an infant or child and then pass the bolus to them to consume. Some other animals chew their food multiple times through a process of chewing, swallowing, regurgitating, and chewing again. This allows them to break down as much of the food as possible before digestion continues.
There are four primary muscles involved in moving the jaw to allow for proper mastication. Three of those muscles are known as the muscles of mastication, or the musculi masticatorii. They control adduction, or closing, of the jaw. The fourth muscle, the lateral pterygoid, is responsible for abduction, or opening, of the jaw. All four of the muscles help with lateral or side-to-side movements. There are additional muscles near the hyoid that also help open the jaw.
The three musculi masticatorii include the masseter, medial pterygoid, and the temporalis. These muscles are attached to both the skull and the mandible, or the lower jaw, and allow for jaw movement. Your lower jaw has two sides, each of which has its own set of mastication muscles.
The following diagram depicts the locations of each muscle around the jaws.
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Now that you know all about mastication, or chewing your food, are you ready to take the quiz? Then let's do a quick review. When you chew your food, you break it up into smaller pieces so that the enzymes released in your mouth can begin their work. During the process, saliva warms and softens the food, the teeth grind it down, and eventually you swallow what's left.
There are four muscles primarily responsible for chewing. The three muscles of mastication help you close your mouth; the last one helps open the mouth. They connect your skull to your jaw bones and aid in the motions of chewing.
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