THE DIGESTIVE SYSTEM

BIG IDEAThe digestive system: provides nutrients energy for your body through the digestion of food THE DIGESTIVE SYSTEM1ObjectiveStudents will learn:How the digestive system provides nutrients and energy to the body through the digestion of food.2What happens During Digestion?Main Idea: During digestion, foods are broken down and absorbed as nourishment or eliminated as waste.DigestionMechanical breakdown of foods within the stomach and intestines for use by the bodys cells.AbsorptionPassage of digested food from the digestive tract into the cardiovascular systemEliminationThe bodys expulsion of undigested food or body wasteDigestion: the mechanical and chemical breakdown of foods within the stomach and intestines by use of the bodys cells.Absorption: The passage of digested food from the digestive tract into the cardiovascular system.Elimination: The bodys expulsion of undigested food or body wastes.3How Digestion WorksMain Idea: The digestion system consists of the mouth, esophagus, stomach and intestines.Mouth--teeth ,salivary glands, tongueEsophagusmuscular tube about 10 inches long that connects the pharynx with the stomachStomachhollow sac organ enclosed in a wall of muscles. These muscles are flexible and allows the stomach to expand when you eat. Intestinespancreas, liver and gallbladder, small and large intestines.

The process of digestion begins with the first bite of food.

Teethbreak food into smaller pieces. Masticationmas-tih-KAY-shunprocess of chewing, prepares food for swallowing.

Salivary glands---produce digestive juices. Saliva contains an enzyme that begins to break down the starches and sugars in food onto smaller particles.

Tongue---prepares chewed food for swallowing.

The uvula, is the small flap of tissue at the back of the mouth, prevents food from entering the nasal passages.

The epiglottistissue covering the throat, prevents food from entering the respiratory system.

EsophagusWhen food is swallowed, it enters the esophagusa muscular tube about 10 inches longconnects the pharynx with the stomach

Stomachhallow sac-like organ in a wall of musclesmuscles are flexable and allow stomach to expand when you eat.

4EsophagusMuscular tube10 inches longConnects pharynx with the stomachPeristalsispare-ih-STAWL-suhsvoluntary muscle contractions that moves food through the digestive tract.The action of peristalsis begins as soon as food is swallowed.

The sphincter musclea circular muscle at the entrance of the stomachallows food to move from the esophagus into the stomach.5The StomachHallowSac-like-organFlexible musclesStomach expands3 tasks1. Mixing foods with gastric juices2.Storing partially digested food and liquid3. Moving food into the small intestines 3 layers in stomach muscles

Gastric juices are secreted from the stomach lining that contains hydrochloric acid and pepsin, an enzyme that digests protein.

Hydrochloric acid kills bacteria

Mucus produced by the stomach forms protective lining so that gastric juices do not harm the stomach.

Holds partially digested food for further digestion before it moves into the small intestine

As food is digested, it is converted into chymea creamy fluid mixture of food and gastric juices.

Peristalsis moves the chyme into the small intestine

3 layers in stomach muscles each move in different directions to aid both mechanical and chemical digestion.Longitudinal , circular and oblique6The Pancreas, Liver and GallbladderPancreas produces enzymesLiver produces bileGlands in walls of intestineIn the small intestine, two juices of the digestive organs mix with the food from the process of digestion.

Bile is yellowish-green in color, is bitter fluid, and is important in the breakdown and absorption of fats.

Bile is stored in the gallbladder between meals

Bile is secreted from the gallbladder into the bile duct

Bile mixes with fats in food

Bile dissolve fats into watery contents

After fat is dissolved, digested by enzymes from pancreas and the lining on the intestines.

Digestion continues in the stomach. 7The Small and Large IntestineSmall IntestineLarge Intestine20-23 feet in length1 inch in diameterConsist of 3 parts: duodenumjejunumileumDigestives juice secreted from small intestine, liver and pancreas90% of all nutrients are absorbed by small intestineVillifinger-like projectionabsorb nutrients5-6-feet long2.5 feet in diameterUnabsorbed materials move by peristalsis into large intestineUndigested parts of food-fiber-roughage is pass into colon Function is to absorb water, vitamins and salts, and to eliminate waste

As chyme enters the duodenum, it contains partially digested

carbohydrates(starches/sugars found in foods which provide your bodys main source of energy)

Villi are lined with capillaries that absorb nutrients.

8Functional and Structural ProblemsFunctionalIndigestionConstipationHeart burnGasNauseaDiarrheaStructuralTooth decayGastritisPeptic ulcerGallstonesLactose intoleranceAppendicitisColitisColon CancerHemorrhoidsCrohns diseaseCirrhosis

Functioning problems---of digestive system may be effected by illness, stress, or eating a particular food.

Indiestionfeeling of discomfort in upper abdomensometimes with gas and nauseacaused by eating too muchtoo quicklyeating spicy foods or high fat foodsor having stomach disorder or stress.

Constipationfeces become dry and hardbowel movement difficultnot having enough water or not consuming fiber to move waste through digestive system.

Heartburnburning sensation in center of chestmay rise to throatresults from acid refluxusing tobaccoalcohol--aspirinor eating greasy spicy greasy foods

Gasnormal with breakdown of foodExcessive gas can result in cramps or uncomfortable feeling of fullness in abdomen.

Nauseafeeling of discomfort that sometimes proceeds vomitingMotion sicknesspathogenssome medications and dehydration can cause nausea.

Diarrheafrequent passage of watery fecescaused by bacterial or viral infectionsa change in eating styleovereatingemotional turmoil,--nutritional deficiencies, Dehydration may result with each episode of dehydration.

Seriousness of structural problems of digestive system can vary. Some problems are temporary or easily treated, others are serious and require immediate medical treatment.

Tooth decaymake is difficult to chew food thoroughly. Brushing teeth daily, regular dental check-upsGastritisinflammation of mucous membrane that lines the stomachincrease production of stomach aciduse of tobaccoalcoholbacterial or viral infections and some medicines can cause gastritissymptomspainindigestiondecrease appetitenausea and vomiting.

Gastritisinflammation of mucous membrane that lines stomachincreased production of stomach aciduse of tobacco/alcoholbacterial/viral infectionssome medicationssymptomspainindigestiondecreased appetite-nausea and vomiting.

Peptic ulcersore in the lining of digestive tractcaused by bacterial infectionover use of aspirinsymptomsabdominal pain that worsens when stomach is emptynauseavomiting and fever--normally broken down by lactasedoes not produce enough lactosesymptomsabdominal campsbloatinggasand diarrheasoy products good replacement for milk/diary products

Appendicitisinflammation of appendix3-4 inch tube at tip of large intestinecan be caused by blockage or bacterial infectionsymptomspain in lower right abdomen and feverdecreased appetitenausea/vomitingmay burst spreading infection throughout abdomendeath may result.

Colitisinflammation of large intestine, or coloncaused by bacterial/viral infectionssymptomsfeverabdominal pain and diarrhea that may contain blood

Colon cancersecond leading cause of death in United Statesusually develops in the lowest part of the colon, near the rectuma low-fat, high-fiber eating plan decreases risk of colon cancer. Any rectal bleeding should be checked by medical professional

Hemorrhoidsveins in the rectum and anus may become swollen and inflamedmay occur with constipation, during pregnancy/after child birth symptomsitchingpainand bleeding

Crohns disease-inflammation of the lining of the digestive tractsymptomsdiarrhea, weight lossfeverand abdominal paincause is unknown seems associated with immune system problems

Cirrhosisscarring of liverprolonged heavy use of alcoholcan lead to liver failure and may cause death.

9The Digestive System

10The Stomach

11Good versus Bad (Liver)

12How the Body Workhttp://kidshealth.org/kid/htbw/13Human Digestive Systemhttp://health.howstuffworks.com/adam-200142.htm

Glencoe Health book pages 422-428

http://kidshealth.org/kid/htbw/14