The Digestive System: Anatomy Digestion: breakdown of foods and the absorption of nutrients...
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Transcript of The Digestive System: Anatomy Digestion: breakdown of foods and the absorption of nutrients...
The Digestive System: AnatomyDigestion: breakdown of foods and the absorption of
nutrientsAlimentary canal includes:
◦ Mouth ◦ Pharynx◦ Esophagus◦ Stomach◦ Small intestine◦ Large intestine◦ Rectum◦ Anus
The Digestive System: AnatomyWalls of alimentary canal consists of:
Mucosa (carries out secretion and absorption)Submucosa (carries away absorbed materials)Muscular layer (provides movement of tube)Serosa (protects underlying tissues)
The Digestive System: AnatomyAccessory organs of alimentary canal include:
TeethTongueSalivary glandsLiverGallbladderPancreas
The AbdomenRight upper quadrant (RUQ):
liver, gallbladder, some of colon and small intestine
Left upper quadrant (LUQ): stomach, spleen, some of colon and small intestine
Right lower quadrant (RLQ): cecum, ascending colon, appendix
Left lower quadrant (LLQ): descending and sigmoid parts of colon
The Abdomen
MouthConsists of lips, cheeks, gums, teeth, tongue
Lined by a mucous membraneRoof is formed by hard and soft palatesSalivary glands produce nearly 1.5 L of saliva daily.Saliva serves as a binder for chewed food and as a mouth lubricant.
OropharynxTubular structure extending vertically from back of mouth
to esophagus and tracheaAutomatic movement of pharynx during swallowing
Moves liquids and solids into esophagus and away from trachea
EsophagusCollapsible tube about 10″ longExtends from end of pharynx to stomachContractions of muscles in the esophagus wall propel food
to the stomach.Liquids pass with little assistance.
StomachHollow organ in left upper quadrantConverts food to mixed, semisolid mass (chyme)
Moves chyme into small bowel in regular, small amounts
PancreasTwo intertwined portions:
Exocrine pancreas secretes pancreatic juiceEndocrine pancreas (islets of Langerhans) produces insulin
Insulin regulates the amount of glucose in blood.
LiverLargest solid organ in abdomenRenders poisonous substances produced by digestion
harmlessForms factors necessary for blood clotting, plasma
production, immune responseProduces bile to help digest fatStores sugar or starch for immediate use
Small IntestineMajor hollow organ of abdomenAbsorbs more than 90% of products of digestion
Into veins to transport to liverComponents include:
DuodenumJejunumIleum
Large IntestineComponents include:
CecumColonRectum
Absorbs final 5% to 10% of digested food and waterForms solid stool to pass out of body through anus
Appendix3″ to 4″ longOpens into cecum (first part of large intestine)Easily becomes infected, producing appendicitis
One of major causes of severe abdominal distress
RectumLowermost end of colonLarge, hollow organStores quantities of feces until expelledAnus is 2″ canal at end, lined with skin.Sphincters (circular muscles) control the escape of liquids,
gases, and solids.Voluntarily and automatically
The Digestive System: PhysiologyFunctions of the digestive system:
IngestionMechanical processingDigestionSecretionAbsorptionExcretion
The Digestive System: PhysiologyIn succession, different secretions (primarily enzymes) are
added to food by:Salivary glandsStomachLiverPancreasSmall intestine
The Digestive System: PhysiologyConverts food into basic sugars, fatty acids, amino acids
These products cross wall of intestine and travel through portal vein to liver
Liver further processes and stores or transports to heart Circulatory system then nourishes all cells