班级： 09 级五班二组 班级： 09 级五班二组 组长：杨磊 组长：杨磊 演讲：朱兴兴 演讲：朱兴兴 时间： 2011/11/15 时间： 2011/11/15

The digestive system

Introduction  digestive tract (gastrointestinal tract, GI tract) (mouth, pharynx, esophagus, stomach, small intestines, and large intestines) and accessory organs (liver, pancreas, gall bladder, teeth, salivary glands).

Functions of the Digestive System: Digestion – chemical break down of food by enzymatic, hydrolysis, or acids Digestion – chemical break down of food by enzymatic, hydrolysis, or acids Ingestion – insert in mouth by conscious choice Ingestion – insert in mouth by conscious choice Absorption – movement across digestive epithelium to interstitial fluids Absorption – movement across digestive epithelium to interstitial fluids Excretion – removal of wastes and indigestible residue Excretion – removal of wastes and indigestible residue

The Oral Cavity (Buccal cavity): bound by (Buccal cavity): bound by the cheeks and lips (labia), the mouth opens into the mouth opens into oral cavity, start of the oral cavity, start of the digestive tract digestive tract

The Teeth Deciduous teeth (20 baby teeth) Deciduous teeth (20 baby teeth) Secondary dentition or permanent teeth (32 adult teeth): Secondary dentition or permanent teeth (32 adult teeth):

Types Incisors – blade shaped teeth at the front of the mouth (8). Single root Incisors – blade shaped teeth at the front of the mouth (8). Single root Cuspids – (canines) conical with a pointed tip (4). Single root Cuspids – (canines) conical with a pointed tip (4). Single root Bicuspids – (premolars) flattened crowns that crush/grind (8). Single or double root Bicuspids – (premolars) flattened crowns that crush/grind (8). Single or double root Molars – large flattened crowns that excel at crush/grind (12). 3 or more roots Molars – large flattened crowns that excel at crush/grind (12). 3 or more roots

The Tongue The Tongue The tongue exends across the floor of the oral cavity and is attached by muscles to the lower jaw bone. papillae can sense flavors,such as sweet,bitter, salty, and sour. papillae can sense flavors,such as sweet,bitter, salty, and sour.

Palate Forms the roof of the mouth. Forms the roof of the mouth. Divided into two parts: the hard palate and the soft palate Divided into two parts: the hard palate and the soft palate

The Pharynx muscles of the pharynx contract and push bolus down to the esophagus. Peristaltic waves push the bolus down the esophagus to the stomach muscles of the pharynx contract and push bolus down to the esophagus. Peristaltic waves push the bolus down the esophagus to the stomach

The Esophagus (or throat) is a long muscular tube that serves as a passageway for food from the mouth to the esophagus and as a passageway for air from nose to the windpipe. (or throat) is a long muscular tube that serves as a passageway for food from the mouth to the esophagus and as a passageway for air from nose to the windpipe.

The Stomach A pouch-like located in the upper part of the abdominal cavity,connects the esophagus with the small intestine. A pouch-like located in the upper part of the abdominal cavity,connects the esophagus with the small intestine. When the stomach is empty, the mucous membranes lining its walls are highly folded; When the stomach is empty, the mucous membranes lining its walls are highly folded; As the stomach fills, the rugae unfolded As the stomach fills, the rugae unfolded

Fundus of stomach Body of stomach Pyloric antrum Pyloric canal Pyloric part Cardia

The Small Intestine (small bowel) is the region of the gut where nearly all of the chemical digestion of the nutritional components of food takes place. (small bowel) is the region of the gut where nearly all of the chemical digestion of the nutritional components of food takes place. Divided into three sections: Divided into three sections: the duodenum, the jejunum, the ileum. the duodenum, the jejunum, the ileum. duodenum jejunum ileum

The Large Intestines Compared with the small intestine, the larger intestine is relatively inactive and has mach less functions. Compared with the small intestine, the larger intestine is relatively inactive and has mach less functions.

The Cecum A pouch on the right side, is connected to the small intestine by the ileocecal valve, which controls the passage of fluid waste from the small intestine into the large intestine. A pouch on the right side, is connected to the small intestine by the ileocecal valve, which controls the passage of fluid waste from the small intestine into the large intestine.

The Colon Which comprised the main length of the large intestine. Which comprised the main length of the large intestine. Has three divisions: the ascending, the transverse, and the descending. Has three divisions: the ascending, the transverse, and the descending. The sigmoid colon, shaped like an S. The sigmoid colon, shaped like an S.

The Rectum Serves as a reservoir for feces.

Accessory Digestive organs The liver The liver The gallbladder The gallbladder The pancreas The pancreas

The Liver A large glandular organ located in the upper right quadrant of abdomen, produces a greenish fluid called bile. A large glandular organ located in the upper right quadrant of abdomen, produces a greenish fluid called bile. Other functions: manufactures blood proteins, removes poisons, sores and releases glycogen. Other functions: manufactures blood proteins, removes poisons, sores and releases glycogen.

The Gallbladder A pear-shaped sac behind the lower portion of the liver, stores bile, which is continuously secreted by the hepatic cells between meals. A pear-shaped sac behind the lower portion of the liver, stores bile, which is continuously secreted by the hepatic cells between meals.

The Gancreas An elongated organ just behind the stomach, manufactures digestive juice containing enzymes (amylase and lipase ) that aid in the digestion of proteins, starches and fats. An elongated organ just behind the stomach, manufactures digestive juice containing enzymes (amylase and lipase ) that aid in the digestion of proteins, starches and fats.

Listening and watching The digestive system The digestive system The digestive system The digestive system

Can you speak them ？ the oral cavity Pharynx Liver Stomach Duodenum Large intestine Esophagus Pancreas Jejunum Ileum Stomach Pancreas Large intestine Stomach Pancreas Jejunum Large intestine Stomach Pancreas Ileum Jejunum Large intestine Stomach Pancreas Duodenum Ileum Jejunum Large intestine Stomach Pancreas Liver Duodenum Ileum Jejunum Large intestine Stomach Pancreas Liver Duodenum Ileum Jejunum Large intestine Stomach Pancreas Esophagus Liver Duodenum Ileum Jejunum Large intestine Stomach Pancreas Esophagus Liver Duodenum Ileum Jejunum Large intestine Stomach Pancreas Esophagus Liver Duodenum Ileum Jejunum Large intestine Stomach Pancreas