Welcome to this lesson on chewing and swallowing. Today, you will be learning about the processes of chewing and swallowing as they are involved in food digestion. Specifically, you will learn about:
- The Mouth
- Mechanical Digestions
- Chemical Digestions
- The Peristalsis
1. The Mouth
The actions of the mouth are the first step in digestion and involve the chewing and swallowing of food. Within the mouth, we have two forms of digestion that are occurring:
- Mechanical digestion
- Chemical digestion
Both are happening in your mouth at the same time to help break down food as the first step in digestion before it reaches the stomach. We're going to take a look at what the difference between these two types of digestion are and where they occur in the mouth.
1a. Mechanical Digestion
is the digestive process that physically breaks down food. Mechanical digestion occurs by physical movements of various digestive organs. In your mouth, an example of mechanical digestion would be when you chew, and your teeth physically break the food down.
- Mechanical Digestion
- The physical breakdown of food into smaller pieces.
1b. Chemical Digestion
also occurs in your mouth (as well as the rest of the alimentary canal) and is when chemicals break down the food. Chemical digestion in your mouth is carried out by enzymes. Enzymes play a role throughout your whole digestive system in chemical digestion.
One specific enzyme in your mouth that's very important is called salivary amylase. Salivary amylase is an enzyme secreted by your salivary glands in your mouth that helps break down starches in the foods that you eat into simple sugars, such as monosaccharides and disaccharides.
- Chemical Digestion
- The breakdown of food by enzymes or chemicals.
- Salivary Glands
- Glands in the mouth which release saliva to aid in the chemical digestion of foods while you chew.
- Salivary Amylase
- An enzyme found in saliva that chemically breaks down starches into simple sugars.
As you're chewing food, your tongue will push the food against your palate, which is also known as the roof of your mouth, and mix it with saliva. Once the mouth is done mechanically and chemically digesting the food, it is then swallowed; the chewed ball of food that is swallowed is called a bolus.
As the food is swallowed, it will move down through your esophagus toward your stomach via peristalsis. Peristalsis is characterized by wave-like contraction of the muscles of the digestive tract that propels food through it. Your esophagus will contract just above the bolus and push it downward. Then, a new contraction will go above it again and push it down farther.
Peristalsis is also how your stomach mechanically breaks the bolus down further, and how the intestines push food through your digestive tract.
- Also known as the "roof" of your mouth; the tongue presses food against the palate and mixes it with saliva to break it down before swallowing.
- The ball of chewed food that is swallowed.
- Wave-like muscle contractions.
This lesson has been an overview of chewing and swallowing and their role in digestion. Specifically, you looked at the role of the mouth, the differences between mechanical and chemical digestion and the role of the peristalsis.
Keep up the learning and have a great day!