Category: Digestive System

The regulation of gastric secretion is accomplished through neural and hormonal mechanisms. Gastric juice is produced all the time but the amount varies subject to the regulatory factors. Regulation of gastric secretions may be divided into cephalic, gastric, and intestinal phases. Thoughts and smells of food start the cephalic phase of gastric secretion; the presence of food in…

The mucosal lining of the stomach is simple columnar epithelium with numerous tubular gastric glands. The gastric glands open to the surface of the mucosa through tiny holes called gastric pits. Four different types of cells make up the gastric glands: Mucous cells Parietal cells Chief cells Endocrine cells The secretions of the exocrine gastric glands – composed of the mucous, parietal,…

The stomach, which receives food from the esophagus, is located in the upper left quadrant of the abdomen. The stomach is divided into the fundic, cardiac, body, and pyloric regions. The lesser and greater curvatures are on the right and left sides, respectively, of the stomach.

The esophagus is a collapsible muscular tube that serves as a passageway between the pharynx and stomach. As it descends, it is posterior to the trachea and anterior to the vertebral column. It passes through an opening in the diaphragm, called the esophageal hiatus, and then empties into the stomach. The mucosa has glands that secrete mucus to keep the lining moist and well lubricated to…

Food is forced into the pharynx by the tongue. When food reaches the opening, sensory receptors around the fauces respond and initiate an involuntary swallowing reflex. This reflex action has several parts. The uvula is elevated to prevent food from entering the nasopharynx. The epiglottis drops downward to prevent food from entering the larynx and trachea in order to direct the food into the esophagus. Peristaltic movements propel the…

A complete set of deciduous (primary) teeth contains 20 teeth. There are 32 teeth in a complete permanent (secondary) set. The shape of each tooth type corresponds to the way it handles food.

The tongue manipulates food in the mouth and is used in speech. The surface is covered with papillae that provide friction and contain the taste buds.

The palate is the roof of the oral cavity. It separates the oral cavity from the nasal cavity. The anterior portion, the hard palate, is supported by bone. The posterior portion, the soft palate, is skeletal muscle and connective tissue. Posteriorly, the soft palate ends in a projection called the uvula. During swallowing, the soft palate and uvula move upward to direct food away from the nasal…

The lips and cheeks help hold food in the mouth and keep it in place for chewing. They are also used in the formation of words for speech. The lips contain numerous sensory receptors that are useful for judging the temperature and texture of foods.

The mouth, or oral cavity, is the first part of the digestive tract. It is adapted to receive food by ingestion, break it into small particles by mastication, and mix it with saliva. The lips, cheeks, and palate form the boundaries. The oral cavity contains the teeth and tongue and receives the secretions from the salivary glands.