digestion 9.3, 9.4. digestion 4 steps ingestion digestion absorption egestion

12
Digestion 9.3, 9.4

Upload: ashley-richards

Post on 05-Jan-2016

255 views

Category:

Documents


1 download

TRANSCRIPT

Page 1: Digestion 9.3, 9.4. Digestion 4 steps ingestion digestion absorption egestion

Digestion

9.3, 9.4

Page 2: Digestion 9.3, 9.4. Digestion 4 steps ingestion digestion absorption egestion

Digestion

4 steps

• ingestion

• digestion

• absorption

• egestion

Page 3: Digestion 9.3, 9.4. Digestion 4 steps ingestion digestion absorption egestion

Simple Organisms

• single-celled organisms

• jellyfish, flatworms have gastrovascular cavity

Page 4: Digestion 9.3, 9.4. Digestion 4 steps ingestion digestion absorption egestion

Complex Animals

• digestive tract with two openings

• why is two openings better than one?

Page 5: Digestion 9.3, 9.4. Digestion 4 steps ingestion digestion absorption egestion

Human Digestive System

Page 6: Digestion 9.3, 9.4. Digestion 4 steps ingestion digestion absorption egestion
Page 7: Digestion 9.3, 9.4. Digestion 4 steps ingestion digestion absorption egestion

Digestion in the Mouth

• physical digestion with teeth

• saliva contains enzyme amylase which digests starch

• mucus helps with swallowing

Page 8: Digestion 9.3, 9.4. Digestion 4 steps ingestion digestion absorption egestion

The Esophagus

• epiglottis closes over the trachea during swallowing

• bolus of food moves to stomach due to peristalsis

• see animation: http://animations.3d4medical.com/Peristalsis-animation_AN2441.html

Page 9: Digestion 9.3, 9.4. Digestion 4 steps ingestion digestion absorption egestion

The Stomach

• sphincters control movement of food in & out of stomach

• gastric juice contains enzymes, acid, and mucus

Page 10: Digestion 9.3, 9.4. Digestion 4 steps ingestion digestion absorption egestion

• hormone gastrin causes release of pepsinogen

• activated by acid to pepsin which digests proteins

• bolus becomes chyme

Page 11: Digestion 9.3, 9.4. Digestion 4 steps ingestion digestion absorption egestion

Acid Reflux

Page 12: Digestion 9.3, 9.4. Digestion 4 steps ingestion digestion absorption egestion

Stomach Ulcers