Which part of the nephron from the following image is the main site of secretion for creatinine?

A. It increases blood pressure, leading to a heart attack or stroke: This is not the primary mechanism of carbon monoxide poisoning.

B. It causes an increase in carbon dioxide, which causes an increase in pH: This is incorrect. Carbon monoxide binds to hemoglobin more tightly than oxygen, not carbon dioxide.

C. It occupies oxygen-binding sites on hemoglobin and decreases the amount of oxygen that reaches the tissues: Carbon monoxide has a high affinity for hemoglobin, leading to reduced oxygen transport in the blood, which can cause tissue hypoxia and death.

D. It causes inflammation within the bronchioles and prevents air from reaching the alveoli: This is incorrect; carbon monoxide poisoning does not work by causing inflammation.

A. Vasa recta: This is a group of capillaries around the nephron loop (loop of Henle), not part of the distal convoluted tubule.

B. Pedicel: These are foot-like projections of podocytes in the glomerulus, not part of the distal convoluted tubule.

C. Bowman's capsule: This surrounds the glomerulus and is part of the filtration process, not the juxtaglomerular apparatus.

D. Macula densa: The macula densa is a group of cells located in the wall of the distal convoluted tubule that senses sodium concentration and regulates blood pressure and filtration rate.