Selasa, Mac 15, 2011

Nota Ringkas: Science Form 3: Chapter 1 : Respiration

FOKUS SPM : FEBRUARI

RESPIRATION
·         Definition : a process in breaking of glucose ( food ) with the presence of oxygen to produce energy / oxidation of food process.
·         During respiration, humans obtain oxygen which at the same time remove carbon dioxide and water vapour through the respiratory system.
·         Oxygen is obtains through breathing.


HUMAN BREATHING MECHANISM

  
STRUCTURE
FUNCTION
NASAL CAVITY
Air entering from the nostrils is led to the nasal cavity

TRACHEA
An airway through which respiratory air travels. The rings of cartilage within its walls keep the trachea open.

BRONCHUS
Passage divided from trachea
 [ singular = bronchus, plural = bronchi ]

BRONCHIOLE
A narrow tube inside the lungs that branches off the main air passages bronchi

ALVEOLUS
Place where exchange of gases take place

RIB CAGE
To protect the lungs and help in breathing mechanism

LUNG
A respiratory organ

INTERCOSTAL MUSCLES
Antagonistic muscles that help the movement of rib cage for breathing mechanism

DIAPHRAGM
A  muscular membrane that separates the thoracic cavity and the abdominal cavity


BREATHING MECHANISM

INHALATION

= a process when air is force into the lungs
EXHALATION

= a process when air is force out of the lungs

External intercostal muscle contract, while internal intercostal muscle relax
Intercostal muscle
External intercostal muscle relax, while internal intercostal muscle contract
Moves upwards and outwards
Rib cage

Move downwards and inwards
Contract and become flat
Diaphragm

Relax and become “dome” shape
Volume increase
Thoracic cavity

Volume decrease
Decrease
Air pressure in the lung

Increase
Air from outside enters the lungs
Air movement

Air is force out of the lungs
**** You just need to memorize 1 process because the other part is just the OPPOSITE

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