Question

6. Why is blood leaving the left ventricle not completely oxygenated? 7. Explain why a chocking person can be helped by pushing on the chest. 8. How do pulmonary capacities and pulmonary volumes compare? 9. What are the effects of aging on the respiratory system? 10. How does exercise affect the chemical nature of the blood? 11. Explain the effect of BPG on RBCs. 12. Why does a negative pleural pressure cause alveoli to expand?

Answer 1

1.

• Blood leaving from the left ventricle not fully oxygenated:
• Oxygenated blood is pumped from heart to the body parts and deoxygenated blood is received from all body parts (not lungs, which receives deoxygenated blood from heart and passes oxygenated blood to heart).
• The right atrium passes deoxygenated blood to right ventricle, which is passed to lungs via pulmonary circulation.
• Blood with 16% oxygen and 5.05% Carbon dioxide is considered as deoxygenated.
• Left atrium passes oxygenated blood to left ventricle which pumps blood through systemic circulation.
• Blood with 21% oxygen and 0.04% Carbon dioxide is considered as oxygenated.
• In the lungs, deoxygenated blood becomes oxygenated by oxygen saturation.
• Hemoglobin exhibits binding capacity of about 1.36 – 1.40 ml of oxygen per gram.
• Thus, the oxygenated blood has about 98 -99 % oxygen saturation and some hemoglobin molecules are still bound to carbon dioxide.
• So the blood received by left ventricle will not be 100% oxygen saturated.