ventilation. After the stress of increased CO2 levels is relieved, ventilation gradually returns to a level slightly above the ventilation level that occurred before hypercapnia. The reason it returns to a level only slightly above the initial ventilation volume relates to a rise in plasma and CSF bicarbonate levels. As a result of the increased plasma and CSF bicarbonate, pH levels are brought back to normal, even though there may still be a high level of CO2. Diving by air-breathing animals During a dive, animals are subjected to periods of hypoxia. Anoxia, severe hypoxic conditions that can result in permanent damage, is a large problem for a mammal’s central nervous system (CNS) and because of this, oxygen must be continuously supplied to the animal. Throughout a dive, animals combat anoxia by making use of oxygen stores in the lungs, blood, and tissues. Animals that dive have higher hemoglobin levels, which increase the oxygen capacity of the blood, and also have larger oxygen stores in muscle ( ) to efficiently supply the body with O2. In order to utilize the stores efficiently during a dive, blood is delivered to the brain and heart first. The tissues and organs to where blood did not go to resort to an anaerobic pathway. As a result, the heart rate slows and cardiac
ventilation. After the stress of increased CO2 levels is relieved, ventilation gradually returns to a level slightly above the ventilation level that occurred before hypercapnia. The reason it returns to a level only slightly above the initial ventilation volume relates to a rise in plasma and CSF bicarbonate levels. As a result of the increased plasma and CSF bicarbonate, pH levels are brought back to normal, even though there may still be a high level of CO2. Diving by air-breathing animals During a dive, animals are subjected to periods of hypoxia. Anoxia, severe hypoxic conditions that can result in permanent damage, is a large problem for a mammal’s central nervous system (CNS) and because of this, oxygen must be continuously supplied to the animal. Throughout a dive, animals combat anoxia by making use of oxygen stores in the lungs, blood, and tissues. Animals that dive have higher hemoglobin levels, which increase the oxygen capacity of the blood, and also have larger oxygen stores in muscle ( ) to efficiently supply the body with O2. In order to utilize the stores efficiently during a dive, blood is delivered to the brain and heart first. The tissues and organs to where blood did not go to resort to an anaerobic pathway. As a result, the heart rate slows and cardiac
Physio-Lecture-Notes.docx