Lesson 15 of 17
The big picture
Show on a big screenTake something in. Carry it to where it is needed. Remove what is left. Many ideas here follow those three steps.
| Idea | Remember | Example |
|---|---|---|
| Three steps | Digestion, absorption, egestion. | Absorption: food into the blood |
| The path | Mouth, food pipe, stomach, small intestine, large intestine, anus. | Most food passes into the blood in the small intestine |
| Saliva | Saliva breaks starch into sugar. | Chewed rice tastes sweet |
| Cow and hen | A cow chews food again. A bird has a gizzard. | Rumination |
| Respiration | Breathing moves air in and out. Respiration uses oxygen to release energy from food. | Breathing only moves air |
| Breathing parts | Lungs, gills, moist skin. | A frog uses more than one |
| Blood | The heart pumps blood. Blood carries food and oxygen. | It takes waste away |
| Leaving | Carbon dioxide leaves with the breath. Undigested food leaves through the anus. Only the second is egestion. | Egestion |
| Air path | Air goes in through the nostrils and nasal passages. It passes down the windpipe and its branches to the alveoli. | Nasal passages trap dust |
| Chest | To breathe in, the diaphragm moves down. The ribs move up and out. To breathe out, both move back. | A curved sheet that flattens |
| Alveoli | Oxygen passes from the air into the blood. Carbon dioxide passes from the blood into the air. | Breathed-out air has more carbon dioxide |
| Villi | Finger-like villi line the small intestine. They give a big surface for absorbing digested food. | Absorption |
Open Chapter 9, Life Processes in Animals in your NCERT book. Read it and remember these pictures.
Next: Life Processes in Plants. A plant has no mouth and no blood. It still does jobs like these.