At which part of the respiratory system does oxygen enter the bloodstream? In the bronchial tube, the alveolus, the heart, or the trachea?

Question

Adeline Allen · Accepted Answer

Oxygen will enter circulatory system from alveoli.

Air is breathed in through external nares and it travels along 'respiratory tree':- at the end of a highly branched respiratory tract air enters alveoli. Wall of alveoli is thin, surrounded by capillary network across which diffusion of gases can take place.

Autumn Anderson · Answer

undefined Oxygen enters the bloodstream in the alveolus.

HIX Tutor · Answer

undefined Oxygen enters the bloodstream in the alveolus. Here's a step-by-step explanation:

1. When we breathe in, air travels through our nose or mouth and down into our trachea (windpipe).
2. The trachea then divides into two bronchial tubes, one for each lung.
3. Each bronchial tube branches out into smaller and smaller tubes called bronchioles.
4. At the end of the bronchioles, there are tiny air sacs called alveoli.
5. The alveoli are surrounded by a network of tiny blood vessels called capillaries.
6. During the process of breathing, oxygen from the air in the alveoli moves across the thin walls of the alveoli and into the capillaries.
7. Oxygen molecules then bind to red blood cells in the capillaries, which are part of the bloodstream.
8. The oxygen-rich blood is then pumped by the heart to deliver oxygen to all the cells of our body.

So, in summary, oxygen enters the bloodstream in the alveolus, which is a part of the respiratory system.