This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'Changes in blood passing through the systemic capillaries are all, EXCEPT: \nSelect and explain. \nA. Increase in hematocrit, B. pH decreases, C. Shift of oxygen dissociation curve to the left., D. Increase in protein content', 'role': 'user'}, {'content': "Answer: C \nExplanation: When blood passes through the capillaries CO2 diffuses from the tissue cells into the blood. This increases the blood PC02 and hence blood H2CO3 and Hydrogen ion conc. The 02-hemoglobin dissociation curve shifts to the right within the capillaries in response to increase in blood C02 and Hydrogen ions. A shift of the curve to the left indicates increased affinity of hemoglobin for oxygen. Ref: Textbook of Medical Physiology By Guyton, 10th Edition, Page 466; Ganong's Review of Medical Physiology, 23rd Edition, Page 667-9.", 'role': 'assistant'}]