班级:班级: 0909 级五班二组级五班二组 组长:杨磊组长:杨磊 演讲:朱兴兴演讲:朱兴兴 时间:时间: 2011/11/152011/11/15
The digestive systemThe digestive system
IntroductionIntroduction digestive tractdigestive tract (gastrointestina (gastrointestinal tract, GI tract) (mouth, pharyl tract, GI tract) (mouth, pharynx, esophagus, stomach, small nx, esophagus, stomach, small intestines, and large intestines) intestines, and large intestines) and accessory organs (liver, paand accessory organs (liver, pancreas, gall bladder, teeth, salivncreas, gall bladder, teeth, saliv
ary glands). ary glands).
Functions of the Digestive Functions of the Digestive SystemSystem::
DigestionDigestion – chemical break down of – chemical break down of food by enzymatic, hydrolysis, or acidsfood by enzymatic, hydrolysis, or acids
IngestionIngestion – insert in mouth by – insert in mouth by conscious choiceconscious choice
AbsorptionAbsorption – movement across – movement across digestive epithelium to interstitial digestive epithelium to interstitial fluidsfluids
ExcretionExcretion – removal of wastes and – removal of wastes and indigestible residueindigestible residue
The Oral CavityThe Oral Cavity
(Buccal cavity): bound by (Buccal cavity): bound by the cheeks and lips (the cheeks and lips (labialabia),), the mouth opens intothe mouth opens into oral cavity, start of theoral cavity, start of the digestive tract digestive tract
TheThe TeethTeeth Deciduous teethDeciduous teeth (20 baby teeth) (20 baby teeth) SSecondary dentition or permanent econdary dentition or permanent
teethteeth (32 adult teeth): (32 adult teeth):
TypesTypes IncisorsIncisors – blade shaped teeth at the fron – blade shaped teeth at the fron
t of the mouth (8). Single roott of the mouth (8). Single root CuspidsCuspids – (canines) conical with a point – (canines) conical with a point
ed tip (4). Single rooted tip (4). Single root BicuspidsBicuspids – (premolars) flattened crown – (premolars) flattened crown
s that crush/grind (8). Single or double rs that crush/grind (8). Single or double rootoot
MolarsMolars – large flattened crowns that exc – large flattened crowns that excel at crush/grind (12). 3 or more rootsel at crush/grind (12). 3 or more roots
The Tongue The Tongue
The tongue exends acroThe tongue exends across the floor of the orass the floor of the oral cavity and is attachel cavity and is attached by muscles to the lod by muscles to the lower jaw bone .wer jaw bone .
papillae can sense flavpapillae can sense flavors ,such as sweet ,bitors ,such as sweet ,bitter, salty, and sour.ter, salty, and sour.
PalatePalate
Forms the roof of the Forms the roof of the mouth.mouth.
Divided into two Divided into two parts: the hard palate parts: the hard palate and the soft palateand the soft palate
TheThe PharynxPharynx
muscles of the pharynx contract and muscles of the pharynx contract and push bolus down to the esophagus. push bolus down to the esophagus. Peristaltic waves push the bolus down Peristaltic waves push the bolus down the esophagus to the stomach the esophagus to the stomach
The EsophagusThe Esophagus
(or throat) is a long (or throat) is a long muscular tube that muscular tube that serves as a serves as a passageway for food passageway for food from the mouth to the from the mouth to the esophagus and as a esophagus and as a passageway for air passageway for air from nose to the from nose to the windpipe. windpipe.
TheThe StomachStomach
A pouch-like located in the upper part A pouch-like located in the upper part of the abdominal cavity ,connects the of the abdominal cavity ,connects the esophagus with the small intestine.esophagus with the small intestine.
When the stomach is empty, the mucoWhen the stomach is empty, the mucous membranes lining its walls are highus membranes lining its walls are highly folded;ly folded;
As the stomach fills, the rugae unfoldeAs the stomach fills, the rugae unfolded d
Fundus of stomach
Body of stomach
Pyloric antrumPyloric canal
Pyloric part
Cardia
The Small IntestineThe Small Intestine
(small bowel) is the (small bowel) is the region of the gut where region of the gut where nearly all of the chemical nearly all of the chemical digestion of the digestion of the nutritional components of nutritional components of food takes place.food takes place.
Divided into three Divided into three sections:sections:
the duodenum, the the duodenum, the jejunum, the ileum. jejunum, the ileum.
duodenuduodenumm
jejunujejunumm
ileumileum
The Large IntestinesThe Large Intestines
Compared with the small intestine, Compared with the small intestine, the larger intestine is relatively the larger intestine is relatively inactive and has mach less functions.inactive and has mach less functions.
The CecumThe Cecum A pouch on the right sA pouch on the right s
ide, is connected to thide, is connected to the small intestine by the small intestine by the ileocecal valve, whie ileocecal valve, which controls the passagch controls the passage of fluid waste from te of fluid waste from the small intestine inthe small intestine into the large intestine. o the large intestine.
The ColonThe Colon Which comprised Which comprised
the main length of the main length of the large intestine.the large intestine.
Has three divisions: Has three divisions: the ascending, the the ascending, the transverse, and the transverse, and the descending.descending.
The sigmoid colon, The sigmoid colon, shaped like an S. shaped like an S.
The RectumThe Rectum
Serves as a reservoir for Serves as a reservoir for feces.feces.
Accessory Digestive organsAccessory Digestive organs
The liverThe liver
The The gallbladdergallbladder
The The pancreaspancreas
The LiverThe Liver A large glandular A large glandular
organ located in the organ located in the upper right quadrant upper right quadrant of abdomen, of abdomen, produces a greenish produces a greenish fluid called bile.fluid called bile.
Other functions: Other functions: manufactures blood manufactures blood proteins, removes proteins, removes poisons, sores and poisons, sores and releases glycogen.releases glycogen.
The GallbladderThe Gallbladder
A pear-shaped sac A pear-shaped sac behind the lower behind the lower portion of the liver, portion of the liver, stores bile, which is stores bile, which is continuously continuously secreted by the secreted by the hepatic cells hepatic cells between meals.between meals.
The GancreasThe Gancreas An elongated organ An elongated organ
just behind the just behind the stomach, stomach, manufactures manufactures digestive juice digestive juice containing enzymes containing enzymes (amylase and lipase ) (amylase and lipase ) that aid in the that aid in the digestion of proteins, digestion of proteins, starches and fats.starches and fats.
Listening and watchingListening and watching
The digestive system The digestive system
Can you speak themCan you speak them ?? the oral cavity
Pharynx
Liver
Stomach
Duodenum Large i
ntestine
Esophagus
Pancreas
Jejunum Ileum
StomachPancreasLarge intestine
StomachPancreas
Jejunum
Large intestine
StomachPancreas
Ileum
Jejunum
Large intestine
StomachPancreas Duodenu
m
Ileum
Jejunum
Large intestine
StomachPancreas
Liver
Duodenum
Ileum
Jejunum
Large intestine
StomachPancreas
Liver
Duodenum
Ileum
Jejunum
Large intestine
StomachPancreas
Esophagus
Liver
Duodenum
Ileum
Jejunum
Large intestine
StomachPancreas
Esophagus
Liver
Duodenum
Ileum
Jejunum
Large intestine
StomachPancreas
Esophagus
Liver
Duodenum
Ileum
Jejunum
Large intestine
StomachPancreas