## Chapter Chosen

Breathing and Exchange of Gases

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CBSE Gujarat Board Haryana Board

## Previous Year Papers

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Class 10 Class 12
Explain the respiratory tract of man.

Respiratory tract of man consists of :

1. External nostrils : The external nares are two slits at the lower end of the nose. These open into the nasal chambers.

2. Nasal chambers : Two nasal chambers are separated from each other by nasal septum. Each chamber has the following three regions :

3. Internal nares (conchae) : The nasal chambers open into the nasopharynx by internal nares.

Fig. Respiratory Organs of man

4. Pharynx : Its upper part is called nasopharynx. The internal nares open into it. Its middle part is called oropharynx and lower part is called laryngopharynx.

5. Larynx : The larynx is called the Adam’s apple and is more prominent in men than in women.

6. Trachea : It is a long thin-walled tube. It extends downward through the neck. In the middle of thorax, it divides into two primary bronchi, one major bronchus enters the right lung and subdivides to form secondary and tertiary bronchi which divide into smaller bronchioles which further divide into alveolar ducts. The latter enter the infundibulum which is made up of central duct and alveoli. All infundibula which get alveolar ducts from one bronchiole is called lobule. The cartilagenous rings are incomplete behind, support the wall of the trachea and bronchi and finally disappear over the bronchioles.

271 Views

Oxygen is carried by haemoglobin as?

Oxyhaemoglobin.
415 Views

Name the cavity having lungs.

Thoracic cavity.
448 Views

By what amount the solubility of carbondioxide is more than the solubility of oxygen?

20 - 25 times
414 Views

What is the partial pressure of oxygen in  oxygenated blood ?

95 mm Hg
702 Views

70% of carbondioxide is transported as ?

Bicarbonate
360 Views