1. through the digestion of food
THE DIGESTIVE SYSTEM
BIG IDEA
The digestive system:
provides nutrients
energy for your body
through the digestion of food

2. Objective Students will learn:
How the digestive system provides nutrients and energy to the body through the digestion of food.

3. What happens During Digestion?
Main Idea:
During digestion, foods are broken down and absorbed as nourishment or eliminated as waste.
Digestion
Mechanical breakdown of foods within the stomach and intestines for use by the body’s cells.
Absorption
Passage of digested food from the digestive tract into the cardiovascular system
Elimination
The body’s expulsion of undigested food or body waste
Digestion: the mechanical and chemical breakdown of foods within the stomach and intestines by use of the body’s cells.
Absorption: The passage of digested food from the digestive tract into the cardiovascular system.
Elimination: The body’s expulsion of undigested food or body wastes.

4. How Digestion Works
Main Idea: The digestion system consists of the mouth, esophagus, stomach and intestines.
Mouth--teeth ,salivary glands, tongue
Esophagus—muscular tube about 10 inches long that connects the pharynx with the stomach
Stomach—hollow sac organ enclosed in a wall of muscles. These muscles are flexible and allows the stomach to expand when you eat.
Intestines—pancreas, liver and gallbladder, small and large intestines.
The process of digestion begins with the first bite of food.
Teeth—break food into smaller pieces. Mastication—mas-tih-KAY-shun—process 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 epiglottis—tissue covering the throat, prevents food from entering the respiratory system.
Esophagus—When food is swallowed, it enters the esophagus—a muscular tube about 10 inches long—connects the pharynx with the stomach
Stomach—hallow sac-like organ in a wall of muscles—muscles are flexable and allow stomach to expand when you eat.

5. Esophagus Muscular tube 10 inches long
Connects pharynx with the stomach
Peristalsis—pare-ih-STAWL-suhs—voluntary muscle contractions that moves food through the digestive tract.
The action of peristalsis begins as soon as food is swallowed.
The sphincter muscle—a circular muscle at the entrance of the stomach—allows food to move from the esophagus into the stomach.

6. The Stomach Hallow Sac-like-organ Flexible muscles Stomach expands
3 tasks—1. Mixing foods with gastric juices—2.Storing partially digested food and liquid—3. 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 chyme—a 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 oblique

7. The Pancreas, Liver and Gallbladder
Pancreas produces enzymes
Liver produces bile
Glands in walls of intestine
In 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.

8. The Small and Large Intestine
Small Intestine
Large Intestine
20-23 feet in length
1 inch in diameter
Consist of 3 parts: duodenum— jejunum—ileum
Digestives juice secreted from small intestine, liver and pancreas
90% of all nutrients are absorbed by small intestine
Villi—finger-like projection— absorb nutrients
5-6-feet long
2.5 feet in diameter
Unabsorbed materials move by peristalsis into large intestine
Undigested 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 body’s main source of energy)
Villi are lined with capillaries that absorb nutrients.

9. Functional and Structural Problems
Indigestion
Constipation
Heart burn
Gas
Nausea
Diarrhea
Structural
Tooth decay
Gastritis
Peptic ulcer
Gallstones
Lactose intolerance
Appendicitis
Colitis
Colon Cancer
Hemorrhoids
Crohn’s disease
Cirrhosis
Functioning problems---of digestive system may be effected by illness, stress, or eating a particular food.
Indiestion—feeling of discomfort in upper abdomen—sometimes with gas and nausea—caused by eating too much—too quickly—eating spicy foods or high fat foods—or having stomach disorder or stress.
Constipation—feces become dry and hard—bowel movement difficult—not having enough water or not consuming fiber to move waste through digestive system.
Heartburn—burning sensation in center of chest—may rise to throat—results from acid reflux—using tobacco—alcohol--aspirin—or eating greasy spicy– greasy foods
Gas—normal with breakdown of food—Excessive gas can result in cramps or uncomfortable feeling of fullness in abdomen.
Nausea—feeling of discomfort that sometimes proceeds vomiting—Motion sickness—pathogens—some medications and dehydration can cause nausea.
Diarrhea—frequent passage of watery feces—caused by bacterial or viral infections—a change in eating style—overeating—emotional 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 decay—make is difficult to chew food thoroughly. Brushing teeth daily, regular dental check-ups
Gastritis—inflammation of mucous membrane that lines the stomach—increase production of stomach acid—use of tobacco—alcohol—bacterial or viral infections and some medicines can cause gastritis—symptoms—pain—indigestion—decrease appetite—nausea and vomiting.
Gastritis—inflammation of mucous membrane that lines stomach—increased production of stomach acid—use of tobacco/alcohol—bacterial/viral infections—some medications—symptoms—pain—indigestion—decreased appetite-nausea and vomiting.
Peptic ulcer—sore in the lining of digestive tract—caused by bacterial infection—over use of aspirin—symptoms—abdominal pain that worsens when stomach is empty—nausea—vomiting and fever--normally broken down by lactase—does not produce enough lactose—symptoms—abdominal camps—bloating—gas—and diarrhea—soy products good replacement for milk/diary products
Appendicitis—inflammation of appendix—3-4 inch tube at tip of large intestine—can be caused by blockage or bacterial infection—symptoms—pain in lower right abdomen and fever—decreased appetite—nausea/vomiting—may burst spreading infection throughout abdomen—death may result.
Colitis—inflammation of large intestine, or colon—caused by bacterial/viral infections—symptoms—fever—abdominal pain and diarrhea that may contain blood
Colon cancer—second leading cause of death in United States—usually develops in the lowest part of the colon, near the rectum—a low-fat, high-fiber eating plan decreases risk of colon cancer. Any rectal bleeding should be checked by medical professional
Hemorrhoids—veins in the rectum and anus may become swollen and inflamed—may occur with constipation, during pregnancy/after child birth– symptoms—itching—pain—and bleeding
Crohn’s disease-inflammation of the lining of the digestive tract—symptoms—diarrhea, weight loss—fever—and abdominal pain—cause is unknown seems associated with immune system problems
Cirrhosis—scarring of liver—prolonged heavy use of alcohol—can lead to liver failure and may cause death.

10. The Digestive System

11. The Stomach

12. Good versus Bad (Liver)

13. How the Body Work

14. Human Digestive System
Glencoe Health book pages