Epithelial cells of the oviduct. Epithelial cells of the epididymis. Epithelial cells of the proximal convoluted tubule. Oxygenated blood enters a liver sinusoid from a branch of the hepatic artery. Bile flows in the direction from triad towards central vein.
Blood nearest the central vein is oxygen-poor.
Hepatocytes nearest the portal triad are exposed to the highest concentrations of blood-borne toxins. During spermatogenesis, the reduction in the number of chromosomes takes place at the first meiotic division. Subcapsular cortical nephrons are most important for concentrating hypertonic urine. Cells of the proximal convoluted tubule are primarily responsible for the active resorption of most of the water and salt. Renin is produced by the cells of the macula densa.