1. Breathing (Ventilation):
- Inhalation: The process of taking air into the lungs. This happens when the diaphragm contracts and flattens, and the rib cage expands, creating negative pressure in the chest cavity that draws air in.
- Exhalation: The process of releasing air from the lungs. This happens when the diaphragm relaxes and returns to its dome shape, and the rib cage contracts, pushing air out.
2. Gas Exchange (Respiration):
- Oxygen Uptake: Tiny air sacs in the lungs called alveoli are surrounded by capillaries (tiny blood vessels). Oxygen from the inhaled air diffuses across the thin walls of the alveoli and into the blood.
- Carbon Dioxide Release: Carbon dioxide, a waste product of cellular metabolism, diffuses from the blood across the capillary walls and into the alveoli to be exhaled.
3. Other Functions:
- Filtering Air: The respiratory system filters incoming air to remove dust, bacteria, and other foreign particles.
- Maintaining pH Balance: The respiratory system helps regulate the pH of the blood by controlling the amount of carbon dioxide exhaled.
- Speech Production: The air expelled from the lungs is used to vibrate the vocal cords, producing sound.
- Sense of Smell: The olfactory receptors located in the nasal cavity are responsible for detecting odors.
In summary, the respiratory system is vital for life by:
* Providing oxygen for cellular processes.
* Removing carbon dioxide, a waste product of metabolism.
* Maintaining a stable pH balance in the blood.
* Enabling speech production.
* Contributing to the sense of smell.
