Group E: Digestive System Chapter. 48 pg. 984-992

1. Group E: Digestive SystemChapter. 48 pg. 984-992 BY: James Lentz, Nile Jones, Hector Ponce, Diego Gutierrez

2. Table of Contents Mouth and Teeth: Hector Ponce, Diego Gutierrez Esophagus and Stomach: James Lentz Intestines: Nile Jones

3. Mouth and Teeth Hector Ponce, Diego Gutierrez

4. Mouth Has saliva that breaks down food particles Saliva helps lubricate food down the esophagus Chamber for ingestion and initial processing Saliva contains hydrolytic enzyme salivary amylase, which initiates the breakdown of the polysaccharide starch into disaccharide maltose

5. Mouth

6. Teeth Teeth is Used for the process of mastication (chewing) Carnivorous teeth are pointed to tear off the meat lack flat grinding surfaces Human teeth have both sharp and flat teeth to eat both plants and meat because we are omnivores

7. Esophagus and Stomach James Lentz

8. Esophagus Esophagus: A muscular tube that the swallowed food enters Muscular contractions of the esophagus move food to the stomach 25 cm long Consist of peristalsis that allow humans to swallow even if they are upside down Peristalsis: Rhythmic waves of muscular contraction The movement of food from the esophagus to the stomach is controlled by a ring of circular smooth muscle called sphincter

9. Esophagus

10. Stomach • A “holding station” involved in acidic breakdown of food • Stomach: saclike portion of the digestive tract • Stomach contains a third layer of smooth muscle for churning food and mixing it with gastric juice • Chief cells secrete pepsinogen, the inactive form of protease pepsin (protein-digesting enzyme) • Moves the food to the intestine by a pyloric sphincter • Gastric Juice: An acidic secretion of tubular gastric glands of the mucosa • Gastric Juice contains • Mucus secreting cells • Parietal cells • Chief cells

11. Stomach

12. Intestines Nile Jones

13. Small Intestines The capacity of the small intestine is limited, and its digestive process takes time Approximately 4.5 m long in a living person, but 6 m when muscles relaxed First 25 cm of the small intestine is the Duodenum The remainder is divided into Jejunum and ileum Digestion occurs in Duodenum and Jejunum Epithelial wall of the small intestine is covered with fingerlike projections name villi Microvilli are cytoplasmic extensions Microvilli also participate in digestion because a number of digestive enzymes are embedded within the epithelial cell’s plasma membrane

14. Large Intestine Also called colon and is much shorter than the small intestine, occupying the last meter of the digestive tract Its called large because of the larger diameter Divided into two structures the cecum and appendix No digestion takes place inside the large intestine Large intestine prepares waste material to be expelled from the body Most bacteria live inside the human colon and excess bacteria are incorporated into refuse material named feces It then lives the body through the rectum

15. Large Intestine

16. True and False Muscular contractions of the esophagus move food to the small intestine Saliva contains polysaccharide starch Epithelial wall of the small intestine is covered with fingerlike projections name villi Teeth is Used for the process of mastication (chewing) Digestion takes place inside of the Large Intestine or the colon

17. Multiple Choice (Fill in all that apply) Gastric Juice contains Hydrolytic enzyme Chief cells Mucus secreting cells Parietal cells All of the above