1. Digestive System

2. Organs of the Digestive System Mouth Mouth Esophagus Esophagus Stomach Stomach Small Intestine Small Intestine Large Intestine Large Intestine Rectum Rectum Anus Anus

3. Functions of the Digestive System 1. Ingestion = Food enters the mouth.

4. Functions of the Digestive System 1. Ingestion = Food enters the mouth. 2. Digestion = Process that breaks food down into small molecules that can be used by cells can be used by cells

5. Functions of the Digestive System 1. Ingestion = Food enters the mouth. 2. Digestion = Process that breaks food down into small molecules that can be used by cells a)Mechanical digestion = Food is chewed, mixed, Food is chewed, mixed, or churned. or churned. b)Chemical digestion = Breaks down large food molecules using chemical reactions

6. Functions of the Digestive System 1. Ingestion = Food enters the mouth. 2. Digestion = Process that breaks food down into small molecules that can be used by cells cells 3. Absorption = Small molecules of food are moved into the bloodstream. the bloodstream.

7. Functions of the Digestive System 1. Ingestion = Food enters the mouth. 2. Digestion = Process that breaks food down into small molecules that can be used by cells 3. Absorption = Small molecules of food are moved into the bloodstream. into the bloodstream. 4. Elimination = Wastes made of unabsorbed food molecules pass out of the body. Large Intestine

8. Which is not a function of the digestive system? a) Breaking down food into molecules the body cells can use b) Absorbing food molecules into the blood to deliver to the body cells c) Changing waste into molecules the body can use d) Eliminating undigested waste from the body

9. Organs of the Digestive Tract 1. Mouth = Digestion starts here.

10. Organs of the Digestive Tract 1. Mouth = Digestion starts here. a)The tongue & teeth mechanically break food up.

11. Organs of the Digestive Tract 1. Mouth = Digestion starts here. a)The tongue & teeth mechanically break food up. b)Saliva chemically digests food. a)Saliva = Mostly made of water, also contains mucus and enzymes, which break food molecules down with chemical reactions.

12. Organs of the Digestive Tract 1. Mouth = Digestion starts here. a)The tongue & teeth mechanically break food up. b)Saliva chemically digests food. a)Saliva = Mostly made of water, also contains mucus and enzymes, which break food down with chemical reactions c)When swallowing, the epiglottis (a small flap of tissue) automatically closes over the trachea (windpipe).

13. Organs of the Digestive Tract 2. Esophagus a)Smooth muscles force food into the mucus-lined esophagus. b)Rhythmic muscular contractions (peristalsis) push food downward.

14. Organs of the Digestive Tract 3. Stomach a)Food undergoes mechanical digestion when stomach muscles churn the food into chyme, a soupy substance. b)Chemical digestion happens when hydrochloric acid (HCl) and pepsin break down the complex proteins. c)Peristalsis pushes the chyme toward stomach’s exit after 2-4 hours.

15. Which is not an example of mechanical digestion? a) Teeth chewing food b) Tongue breaking up food c) Smooth muscles in stomach churning food d) Hydrochloric acid breaking down proteins

16. Organs of the Digestive Tract 4.Small Intestine (4-7 meters long) a)Mechanical & Chemical digestion happen here. b)Intestinal juice (full of enzymes) breaks down food.

17. Organs of the Digestive Tract 4.Small Intestine (4-7 meters long) a)Mechanical & Chemical digestion happen here. b)Intestinal juice (full of enzymes) breaks down food. c)Accessory Organs Liver = Bile isLiver = Bile is produced here (Bile breaks up fats like dish detergent breaks up grease.).

18. Organs of the Digestive Tract 4.Small Intestine (4-7 meters long) a)Mechanical & Chemical digestion happen here. b)Intestinal juice (full of enzymes) breaks down food. c)Accessory Organs Liver = Bile is producedLiver = Bile is produced here (Bile breaks up fats like dish detergent breaks up grease.). Gall bladder = BileGall bladder = Bile is stored here until released into the small intestine.

19. Organs of the Digestive Tract 4.Small Intestine (4-7 meters long) a)Mechanical & Chemical digestion happen here. b)Intestinal juice (full of enzymes) breaks down food. c)Accessory Organs Liver = Bile is producedLiver = Bile is produced here (Bile breaks up fats like dish detergent breaks up grease.). Gall bladder = Bile isGall bladder = Bile is stored here until released into the small intestine. Pancreas = Produces Pancreas = Produces pancreatic juices, like insulin, that are released into the small intestine to break down starches

20. Organs of the Digestive Tract 4.Small Intestine (4-7 meters long) a)Mechanical & Chemical digestion happen here. b)Intestinal juice (full of enzymes) breaks down food. c)Accessory Organs LiverLiver Gall bladderGall bladder PancreasPancreas d)Digested food is absorbed through the villi, ridges in the small intestine, into capillaries that carry the nutrients to all of the body cells.

21. Organs of the Digestive Tract 4.Small Intestine (4-7 meters long) a)Mechanical & Chemical digestion happen here. b)Intestinal juice (full of enzymes) breaks down food. c)Accessory Organs Liver, Gall bladder, PancreasLiver, Gall bladder, Pancreas d)Digested food is absorbed through the villi into capillaries that carry the nutrients to all of the body cells. e) By the time food leaves the small intestine, it is empty of all nutrients except water.

22. Where does absorption of nutrients take place? a) Mouth b) Stomach c) Small intestine d) Liver

23. Organs of the Digestive Tract 5.Large Intestine (1.5 meters long) a)Undigested food spends 18–24 hours here, and most of the water is re-absorbed. This waste material is now called feces.

24. Organs of the Digestive Tract 5. Large Intestine (1.5 meters long) a)Undigested food spends 18–24 hours here, and most of the water is re-absorbed. b)Helpful bacteria living in the large intestine make vitamins B and K.

25. Organs of the Digestive Tract 5. Large Intestine (1.5 meters long) a)Undigested food spends 18–24 hours here, and most of the water is re-absorbed. b)Helpful bacteria living in the large intestine make vitamins B and K. c)Materials not absorbed form into solid waste (dead bacteria, some fat and protein, undigested food, dried out parts of digestive juices, and old intestinal cells).

26. Organs of the Digestive Tract 5. Large Intestine (1.5 meters long) a)Undigested food spends 18–24 hours here, and most of the water is re-absorbed. b)Helpful bacteria living in the large intestine make vitamins B and K. c)Materials not absorbed form into solid waste (dead bacteria, some fat & protein, undigested food, dried out parts of digestive juices, and old intestinal cells). d)Solid waste passes into the rectum and is stored until it is eliminated from the body through the anus.

27. Organs of the Digestive Tract 6. Large Intestine (1.5 meters long) Attached to the large intestine is a worm-like structure called the appendix. Little is understood about the function of the appendix. The function of the appendix is unknown. One theory is that the appendix acts as a storehouse for good bacteria, “rebooting” the digestive system after illnesses. Other experts believe the appendix played a part in the digestion of early-man’s diet.