CLASS 6TH | RESPIRATORY SYSTEM | REVISION NOTES

Respiration – The process, in which the energy is released by breaking down food for
life activities, is called respiration.

Stages of Respiration – The process of respiration take place in two stages –

Breathing or external respiration – It involves the inhalation of oxygen rich air and
exhalation of carbon dioxide rich air.
Cellular or internal respiration – It causes breakdown of glucose with the help of
oxygen into CO2, water and energy.
C6H12O6 (Glucose) + 6O2 (Oxygen) 6CO2 (Carbon dioxide) + 6 H2O + Energy (38 ATP)

Site for respiration – This process partially takes place in cytoplasm and partially in
mitochondria of the cell.

Types of Respiration –

Aerobic Respiration – This respiration results in the breakdown of glucose in the
presence of oxygen.
Anaerobic – This respiration results in the breakdown of glucose in the absence of oxygen.
C6H12O6 2 C2H5OH + 2CO2 + 2ATP

Respiratory System in Humans –
The passage through which the exchange of gases takes place is called respiratory tract. It
involves various organs like nose, nostrils, nasal cavity, pharynx, larynx, trachea, bronchi,
bronchioles, alveolar sacs, and alveoli.

Exchange of gases –
In this process, we inhale oxygen rich and exhale carbon dioxide rich air.
Breathing – It is the process by which we take oxygen rich air in our body and air rich in
carbon dioxide is taken out from our body.
Breathing rate – breathing rate of a woman is faster than a man and it is not always
constant.
For an adult – 15 to 18 times in a minute

Mechanism of breathing – Breathing takes place in lungs. The air passes through nasal
cavity and windpipe and reaches to lungs. Breathing involves the movement of ribcage and
diaphragm.

It includes –
Inspiration or inhalation – taking in oxygen
Expiration or exhalation – giving our carbon dioxide

Common respiratory diseases –

 Asthma – caused due to allergy and respiratory passage becomes swollen and
constricted.
 Bronchitis – it is the swelling of lining of bronchial tube. It makes breathing difficult.
 Pneumonia – it is the inflammation of lungs tissue.
 Tuberculosis – it is the infectious disease that affects the lungs