natural science alfonso

NOMBRE : ALFONSO SANZ VELASCO

CURSO: 6º DE PRIMARIACOLEGIO : CRA ENTRE

DOS RIOS AULAS DE CABEZUELA

THE RESPIRATORY SYSTEM Our cells need oxygen (02) to combine with

nutrients and to produce energy. During this process , the cells produce carbon dioxide (co2) that has to be expelled from the body . To obtain oxygen and get rid of carbon dioxide we use our respiratory system.

RESPIRATION When we take a breath ,air enters through the nose

and mouth . It passes down the pharynx and then to the trachea (or windpipe).

The trachea divides into two tubes called bronchi. Each bronchus then subdivides into smaller and smaller bronchi . The smallest are bronchioles.

At the end of each bronchiole is a cluster of tiny air sacks called alveoli. Lungs have about 600 million alveoli . The alveoli are covered with a network of capillaries . Gas exchange takes place in the alveoli . Oxygen passes from the alveoli to the capillaries and into the blood.

At the same time carbon dioxide leaves the blood and enters the alveoli . The air carrying carbon dioxide goes through the bronchioles to the bronchi and the trachea and finally out through the mouth and nose.

PICTURES

INHALATION When we take a breath ,our diaphragm ,

the big muscle under the lungs,contracts and flattens to allow the lungs to inflate . The ribs expand and move up to make more room.

PICTURES

PICTURES

EXHALATION When we breath out , the ribs relax and

move back in. The diaphragm relaxes and moves up, pushing the carbon dioxide out of the lungs and back up the trachea , out of the nose and mouth.

PICTURES

PICTURES

THE

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