Main cause of emphysema, a serious disease of respiratory tract is:
Polluted water
Tobacco smoking
Uncooked food
Polluted air
Air can enter the body and travel to the lungs :
through the mouth and the nose.
through the oesophagus and gullet.
through the windpipe and the pores.
through the nose and the nervous system.
1. Only very few cells are exposed to the environment. 2. They have high oxygen requirements .3. Their respiration is complex than inactive animals.
What body structure protects the lungs from outside harm?
Cartilage
Tiny sacs
The rib cage
The diaphragm
The respiratory control center of humans is located in the:
blood-brain barrier
alveoli
erythrocytes
brainstem (medulla oblongata)
The expansion of the lung and inhalation of air are in part the result of:
the muscles of the lungs relaxing, allowing the lungs to get larger.
decreased pressure of the interpleural fluid.
the contraction of the muscles of the diaphragm.
the muscles of the lungs relaxing, allowing the lungs to get smaller.
What is the percentage of CO2 in the air we breathe out?
0.03%
4%
6%
2%
