The pathway of air into the body: Flashcards
1.
Air enters the body via the nostrils or mouth.
2
Air then travels down the throat via the larynx and trachea.
3
Air goes into the lungs via the main-stem bronchi.
4
One main-stem bronchus ends in the left lung and one in the right lung
5
In the lungs, the main-stem bronchi divide into smaller bronchi.
6
The smaller bronchi divide into even smaller tubes (bronchioles).
7
Bronchioles lead to tiny air sacs (alveoli) in which the trade of oxygen and carbon dioxide occurs.
i.e. gaseous exchange
Explain the process of gaseous exchange at the alveoli.
Gaseous exchange occurs in the alveoli by a process called diffusion, which occurs between the surface of alveoli and pulmonary capillary beds. Oxygen, once inhaled into the lungs, is passed from the alveoli into the bloodstream for distribution to the rest of the body. This occurs because there is a higher concentration of O2 in the alveoli than in the blood. There, O2 diffuses across to the capillaries where there is a lower concentration. At the same time, CO2 goes from the high concentration in the capillaries to a low concentration in the alveoli and is breathed out during exhalation.
Outline the role of hemoglobin in oxygen transport
Most (98.5%) of oxygen in the blood is transported by hemoglobin as oxyhemoglobin within red blood cells.
Hemoglobin is the protein that allows oxygen to bind to a red blood cell.
8
Oxygen from inhaled air combines with the hemoglobin present in the blood and travels throughout the body to reach every cell.
movemnt of air
As the air is drawn in during inhalation, it is warmed in the nasal passages, and cleaned andmoistened by mucus lining the nasal passages and trachea. The mucus is moved to the throat bycilia (microscopic hairs) lining the nasal passages and trachea, and is swallowed. The air passes through the bronchi and bronchioles and enters the alveoli where gaseous exchange occurs between the airand the blood in the capillaries.
