PATHWAY OF AIR FLOW DURING BREATHING
Trace the pathway of anatomical structures through which a molecule of oxygen would pass as it enters the body through the nostrils and travels down to an alveolus in the lungs.
Answers
The oxygen molecule floating through the air is breathed in through the mouth and nose during inhalation. It travels from the mouth and nose into the pharynx (oropharynx and nasopharynx). The epiglottis closes to prevent foreign objects from entering the trachea (windpipe). From the pharynx, oxygen passes by larynx (voice box) through the trachea. The trachea splits into two mainstream branches called bronchi that go into each lung. The oxygen once in each bronchi, travels through smaller branches called bronchioles and then to the Alveoli. The oxygen molecule passes through or filters through the alveoli. Small pulmonary capillaries pass by the alveoli. When oxygen travels through the alveoli, the oxygen molecule transfers to or jump onto the hemoglobin molecule in the red blood cells of the blood through the thin walls in the alveoli and through the pulmonary and alveolar capillaries thus creating oxygen-rich blood. At the same time, carbon dioxide, a waste product of the body cells, transfers from or jumps off the hemoglobin molecule and is expelled during exhalation. This is commonly known as the gas exchange that takes place in the lungs.
The oxygen molecule in the blood (oxygen-rich blood) travels from the lungs to the heart through the pulmonary veinioles, pulmonary veins, and into the left atrium in order to provide the heart with oxygen. The oxygen molecule (oxygen-rich blood) travels from the left atrium through the bicuspid (mitral) valve and into the chamber below it, the left ventricle. From the left ventricle the oxygen molecule (oxygen-rich blood) then is pumped out of the heart through the aortic semi-lunar valve, into the aorta (largest artery), and then out to the body in order to provide the body with oxygen. The oxygen molecule (oxygen-rich blood) travels throughout the body through arteries then arterioles until it reaches the capillary beds in the tissues. While blood is in the capillary beds, the oxygen molecule transfers to or jump off the hemoglobin molecule in the red blood cells of the blood through the thin walls in the capillaries and then supplies cells and tissues with oxygen. At the same time, carbon dioxide, a waste product of the cells moves the opposite direction through the capillary walls, to be picked up by the blood in which they would transfer to or jump onto the hemoglobin molecule. This is commonly known as the gas exchange that takes place at the cellular level.