What do inspiration and expiration have in common?
They both use the same pathways.
The air travels in the same direction in both.
They both end in the lungs.
They both conduct air from the outside.
They both remove wastes from the tissues.
The correct answer and explanation is:
Correct Answer: They both use the same pathways.
Explanation:
Inspiration (inhalation) and expiration (exhalation) are the two phases of the respiratory cycle, which together enable the exchange of gases (oxygen and carbon dioxide) in the body. Both processes share several features and structures, the most significant of which is that they utilize the same anatomical pathways in the respiratory system.
1. Shared Pathways:
The air passes through the same anatomical structures during inspiration and expiration. These structures include the nasal cavity, pharynx, larynx, trachea, bronchi, and bronchioles, leading to the alveoli in the lungs. During inspiration, air travels from the external environment through these pathways into the lungs. During expiration, air follows the same pathways but in the opposite direction, moving from the lungs to the outside.
2. Purpose of Inspiration and Expiration:
The primary goal of inspiration is to bring oxygen-rich air into the lungs so it can be absorbed into the bloodstream. Expiration, on the other hand, expels carbon dioxide (a waste product of cellular respiration) from the body. Despite having opposite purposes, they rely on the same structures to move air.
3. Mechanism:
Both processes are driven by the contraction and relaxation of the diaphragm and intercostal muscles, which create changes in thoracic pressure. These pressure changes facilitate the movement of air through the same pathways.
Why Other Options Are Incorrect:
- The air travels in the same direction: Air travels in opposite directions during inspiration and expiration.
- Both end in the lungs: Expiration ends with air exiting the body, not in the lungs.
- Conduct air from the outside: Expiration removes air from the lungs.
- Remove wastes from tissues: Only expiration removes carbon dioxide waste.
By sharing pathways, inspiration and expiration are interconnected and rely on the same anatomy for efficient gas exchange.