Bile canaliculi, about 0.5-1.0 micrometer in
diameter, are formed by the cytoplasmic membranes of adjacent
hepatocytes. They therefore have no wall of their own. The bile
canaliculi are not easily seen in conventional preparations, but they
are revealed by special staining methods, such as Golgi's silver
impregnation. In the plane of the hepatic plate, each hepatocyte is
surrounded by a hexagonal network of bile canaliculi. The canaliculi
anastomose with one another to form a three-dimensional network. In the
periphery of the lobule, they connect with the canal of Hering, which
drains into the bile duct in the portal triad.
Bile contains bile salts, bilirubin, and steroids;
bile salts are associated with the digestion and absorption of fats. The
bile made by the hepatocytes is first secreted into the lumen of the
bile canaliculi. When bile canaliculi are broken because of the necrosis
of hepatocytes or obstruction of the bile duct, bile enters the blood
stream through the space of Disse, resulting in the accumulation of
bilirubin. Bilirubin is a metabolic product of hemoglobin and imparts a
yellow appearance to the skin and sclera, a condition known as jaundice.