Question

2. How are oxygen and carbon dioxide are transported in the blood?

3. Hyperventilation is used by swimmers before they dive. Why? Also, why is that fatal?

4. What happens to the cardiac output when there is a tamponade (buildup of pericardial fluid)? Why is this fatal?

Answer 1

Answer for question no.2

Once oxygen reaches to lungs by inspiration ,oxygen starts diffusing through the alveoli and then enters into bloodstream,reaches to body tissues.Oxygen gets transported by dissoving in blood and combinin with the hemoglobin in erythrocytes of blood. Then oxygen binds to the iron part of the hemoglobin and forms oxyhemoglobin ,a weak acid.Oxyhemoglobin releases the oxygen by addition of H+ ion from the cell . Oxygen release at tissue from hemoglobin is possible due to difference in arterial and venous blood.

Carbon dioxide gets trasported in blood from tissues.It occurs via three distinct pathways - 1) carbon dioxide dissolve directly into blood 2)carbon dioxide binds to plasma proteins or combine with hemoglobin in red blood cell called as caraminohemoglobin. Carbaminohemoglobin once reaches to the alveoli ,carbondioxide get released from hemoglobin and expiration of carbon dioxide occurs.3) majority of the carbon dioxide gets transported to lung by bicarbonate buffer system. conversion of carbon dioxide into carbonic acid occurs in red blood cells ,carbonic acid dissociates into bicarbonate ion and hydrogen ion. Hydogen ion binds with hemoglobin and alters the pH .Due to change in pH ,bicarbonate ion gets out of the red blood cell in exchange of chloride ion through chloride shift . In lung, Hydrogen ion binds to the bicarbonate ion and leaves hemoglobin.Therefore produces carbonic acid intermediate and get converted into carbon dioxide by the action of carbonic anhydrase. Finally, carbon dioxide comes out from lung through expiration.