Explain respiratory system of human.
In human beings, the air is taken into the body through
the nostrils. The air passing through the nostrils is filtered by
fine hairs that line the passage. The passage is also lined with
mucus which helps in this process. From here, the air passes
through the throat and into the lungs. Rings of cartilage are
present in the throat. These ensure that the air-passage does
not collapse. Within the lungs, the passage divides into smaller and smaller
tubes which finally terminate in balloon-like structures which
are called alveoli (singular–alveolus). The alveoli provide a surface
where the exchange of gases can take place. The walls of the alveoli
contain an extensive network of blood vessels. As we have seen
in earlier years, when we breathe in, we lift our ribs and flatten
our diaphragm, and the chest cavity becomes larger as a result.
Because of this, the air is sucked into the lungs and fills the expanded
alveoli. The blood brings carbon dioxide from the rest of the body
for release into the alveoli, and the oxygen in the alveolar air is
taken up by the blood in the alveolar blood vessels to be transported
to all the cells in the body. During the breathing cycle, when air is
taken in and let out, the lungs always contain a residual volume
of air so that there is sufficient time for oxygen to be absorbed
and for the carbon dioxide to be released.
In human beings, the air is taken into the body through the nostrils. The air passing through the nostrils is filtered by fine hairs that line the passage. The passage is also lined with mucus which helps in this process. From here, the air passes through the throat and into the lungs. Rings of cartilage are present in the throat. These ensure that the air-passage does not collapse. Within the lungs, the passage divides into smaller and smaller tubes which finally terminate in balloon-like structures which are called alveoli (singular–alveolus). The alveoli provide a surface where the exchange of gases can take place. The walls of the alveoli contain an extensive network of blood vessels. As we have seen in earlier years, when we breathe in, we lift our ribs and flatten our diaphragm, and the chest cavity becomes larger as a result. Because of this, the air is sucked into the lungs and fills the expanded alveoli. The blood brings carbon dioxide from the rest of the body for release into the alveoli, and the oxygen in the alveolar air is taken up by the blood in the alveolar blood vessels to be transported to all the cells in the body. During the breathing cycle, when air is taken in and let out, the lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.
