Digestive system

Teeth Two different sets of teeth form during development. The first set, the primary teeth (deciduous teeth), usually erupt through the gums at regular intervals between the ages of six months and two to four years. There are twenty deciduous teeth—ten ...

Minerals Dietary minerals (min′er-alz) are inorganic elements essential in human metabolism. Plants usually extract these elements from soil, and humans obtain them from plant foods or from animals that have eaten plants. Characteristics of Minerals Minerals contribute about 4% of body weight and ...

Vitamins Vitamins (vi′tah-minz) are organic compounds (other than carbohydrates, lipids, and proteins) required in small amounts for normal metabolism, that cells can not synthesize in adequate amounts. Therefore, they are essential nutrients that must come from foods. Vitamins are classified on the basis ...

Large Intestine The large intestine is so named because its diameter is greater than that of the small intestine. This part of the alimentary canal is about 1.5 meters long. It begins in the lower right side of the abdominal cavity, ...

SMALL INTESTINE The small intestine is a tubular organ that extends from the pyloric sphincter to the beginning of the large intestine. With its many loops and coils, it fills much of the abdominal cavity. The small intestine receives secretions from ...

Liver The liver is in the upper right quadrant of the abdominal cavity, just inferior to the diaphragm. It is partially surrounded by the ribs, and extends from the level of the fifth intercostal space to the lower margin of the ribs. The ...

Stomach The stomach is a J-shaped, pouchlike organ that hangs inferior to the diaphragm in the upper left portion of the abdominal cavity and has a capacity of about 1 liter or more. Thick folds (rugae) of mucosal and submucosal layers ...

Pharynx and Esophagus The pharynx is a cavity posterior to the mouth from which the tubular esophagus leads to the stomach. The pharynx and the esophagus do not digest food, but both are important passageways whose muscular walls function in swallowing. Structure ...

Salivary Glands The salivary (sal′ı¯-ver-e) glands secrete saliva. This fluid moistens food particles, helps bind them, and begins the chemical digestion of carbohydrates. Saliva is also a solvent, dissolving foods so that they can be tasted, and it helps cleanse the ...