Digestion:
Changing the food from a complex form into a simple one to let the body get Benefited
Absorption
Digested food is absorbed through the small intestine walls then it reaches blood which distributes it all over the body organs.
Respiration:
Is the process in where the air rich in oxygen enters into the two lungs and the air rich in carbon dioxide released outside the two lungs.
-The more active your body is, the more your respiration times increases.
The fish inhales the dissolved oxygen in water by gills
Process of inhalation
- The diaphragm muscle contracts and moves down and the thoracic cavity enlarges.
- The air rich in oxygen enters the two lungs through the nasal passage
Process of exhalation
-The diaphragm muscle relaxes and moves up and the thoracic cavity become narrow. - The air rich in carbon dioxide moves outside the lungs
Exchange of gases Exchange of gases occurs between the air existed in alveoli and the blood capillaries where blood leaves carbon dioxide and carries the oxygen and distributes it
الأربعاء أبريل 16, 2014 6:48 pm من طرف shahd mohamed
Ahlamontada 
اليومية
موضوع: science revision for junior 4