The diagram shows a simplified schematic of a liver lobule showing the blood vessels associated with hepatic function and excretion.
Following a protein-rich meal, excess amino acids undergo deamination in the hepatocytes to produce ammonia, which is subsequently converted into urea via the ornithine cycle.
Which of the labelled vessels, W, X, Y, or Z, will contain blood with the highest concentration of urea?
W
X
Y
Z