via Wikimedia CommonsĪ fleshy bead of tissue called the uvula drops down from the center of the posterior edge of the soft palate. Including uvula, teeth, tongue, soft palate, and palatoglossal arch. You can therefore manipulate, subconsciously, the soft palate-for instance, to yawn, swallow, or sing (see Figure 12.2). This part of the palate, known as the soft palate, is composed mainly of skeletal muscle.
If you run your tongue along the roof of your mouth, you’ll notice that the hard palate ends in the posterior oral cavity, and the tissue becomes fleshier. It is created by the maxillary and palatine bones of the skull and, given its bony structure, is known as the hard palate. The anterior region of the palate serves as a wall (or septum) between the oral and nasal cavities as well as a rigid shelf against which the tongue can push food. The next time you have food in your mouth, notice how the arched shape of the roof of your mouth allows you to handle both digestion and respiration at the same time. When you are chewing, you do not find it difficult to breathe simultaneously. The main open area of the mouth, or oral cavity proper, runs from the gums and teeth to the fauces. The pocket-like part of the mouth that is framed on the inside by the gums and teeth, and on the outside by the cheeks and lips is called the oral vestibule. The structures of the mouth are illustrated in Figure 12.2. Peristalsis, a wave-like muscle movement, pushes food along.Īlso called the oral cavity (or buccal cavity). Food doesn’t need gravity to reach your stomach. ISSN 2002-4436., CC BY 3.0, via Wikimedia Commons. All digestive organs play integral roles in the life-sustaining process of digestion. Figure 12.1 Components of the Digestive System. Although the small intestine is the workhorse of the system, where the majority of digestion occurs, and where most of the released nutrients are absorbed into the blood or lymph, each of the digestive system organs makes a vital contribution to this process (see Figure 12.1). The function of the digestive system is to break down the foods you eat, release their nutrients, and absorb those nutrients into the body. This chapter examines the structure and functions of these organs, and explores the mechanics and chemistry of the digestive processes. In short, whether you pay attention or not, the organs of the digestive system perform their specific functions, allowing you to use the food you eat to keep you going. By the time any waste material is excreted, the body has appropriated all it can use from the apple. You may be taking a walk or studying or sleeping, having forgotten all about the apple, but your stomach and intestines are busy digesting it and absorbing its vitamins and other nutrients. Of course, you enjoy the apple’s taste as you chew it, but in the hours that follow, unless something goes amiss and you get a stomachache, you don’t notice that your digestive system is working. Consider what happens when you eat an apple. The digestive system is continually at work, yet people seldom appreciate the complex tasks it performs in a choreographed biologic symphony.
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