Tuesday, January 4, 2011

Salam lagi..

Glitter Photos

Suka...suka...happy sgt2...sebabnya..cgu tak sangka ramai anak murid cgu dah rajin2 sekrg nie...harap2 ia berkekalan sampai akhir tahun...oops...sampai PMR...hehehe...

Terima kasih kerana memberikan cgu lebih semangat utk mengajar...suka dan happy sgt2 sebab tanpa cgu suruh @ pesan pun...anak2 murid cgu dh buat latihan ...teruja sgt...mcm nie lebih semangat cgu nak mengajar....
Ok...cgu copy & paste notes dan gamabr yg cantik2 nie utk sesiapa yg berminat nk baca ye...mudah2 ia berguna...

Inspiration or Inhalation

During inhalation the external intercostal muscles contract, which raises the chest cavity or the ribs. This is accompanied by the lowering of the diaphragm. Together these movements serve to increase the area of the thoracic cavity, which reduces the pressure. The air from outside rushes into the lungs.
inspiration or inhalation in human beings 

Expiration or Exhalation

The internal intercostal muscles contract bringing the ribs back to the original position and the diaphragm is also raised back by the action of the abdominal muscles. This reduces the space in the chest cavity and increases the pressure. This expels the air out of the lungs.

expiration or exhalation in human beings 

Demonstration of Breathing Mechanism

Take a bell jar. Towards its rounded end, fix a 'Y' shaped glass tube and on the open ends of the two branches tie a balloon each. On its open end tie a thin rubber sheet. The cavity of the bell jar acts as the thoracic cavity, the "Y" shaped tube as the trachea that branches into bronchi and the rubber sheet as the diaphragm.
experiment demonstrating inspiration
 To demonstrate inspiration, pull the rubber sheet down. The balloons get inflated. This shows how the lungs are filled with air when the diaphragm moves down.

How are the Balloons Inflated?

When the rubber sheet is pulled down, the volume of the cavity increases. This brings the pressure down. Low pressure inside the jar brings the air rushing in through the tubes and inflates the balloon.
experiment demonstrating expiration
To demonstrate expiration, the rubber sheet is allowed to go back to its original position. The balloons get deflated. This shows how the lungs are deflated when the diaphragm comes back to its original position.

How are the Balloons Deflated?

When the rubber sheet goes back to its position, the volume in the jar is reduced and the pressure is increased. This pushes the air out of the balloons.
 Ok...next time kita sambung lagi...bye


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