Question 1

What are hepatocytes and what is their primary role in the liver?

Accepted Answer

Hepatocytes are specialized epithelial cells arranged in branched, irregular three-dimensional plates called hepatic laminae. They perform critical functions including blood detoxification and bile secretion. These versatile cells also store glucose as glycogen, produce plasma proteins from amino acids, and convert harmful ammonia into urea, making them essential for metabolic processing.

Question 2

How does bile move through the liver after hepatocytes secrete it?

Accepted Answer

Hepatocytes secrete bile into small ducts called bile canaliculi. From there, bile flows into bile ductules and subsequently into larger bile ducts. This organized ductal system ensures efficient bile transport and delivery to the gallbladder and small intestine for digestive functions.

Question 3

What structures make up the portal triad and where is it located?

Accepted Answer

The portal triad comprises three key structures: a branch of the hepatic artery, a branch of the hepatic portal vein, and a bile duct. Located at each corner of the liver lobule, the portal triad ensures delivery of oxygen-rich arterial blood and nutrient-laden venous blood to hepatocytes while facilitating bile drainage.

Question 4

What role do liver sinusoids play in hepatic blood flow?

Accepted Answer

Liver sinusoids are enlarged, heavily fenestrated vessels positioned between hepatocyte plates that collect blood from the portal triads. Blood flows through these sinusoids and empties into the central vein, eventually reaching hepatic veins that drain into the inferior vena cava. This arrangement enables efficient nutrient and oxygen delivery to hepatocytes.

Question 5

How do stellate macrophages contribute to liver function?

Accepted Answer

Stellate macrophages, also called hepatic macrophages or Kupffer cells, are star-shaped cells embedded in sinusoid walls. They filter blood by removing debris such as bacteria and worn-out blood cells, protecting the body from harmful substances and maintaining blood quality as it circulates through the liver.

Question 6

What is the hepatic acinus and why is it significant?

Accepted Answer

The hepatic acinus is the most accepted anatomical arrangement of hepatocytes, portal triads, and sinusoids within the liver. This organizational model explains how the liver's structural components work together to facilitate blood detoxification, nutrient processing, and bile production in a coordinated, efficient manner.

Question 7

How much bile do hepatocytes produce daily and what cellular structures enable this?

Accepted Answer

Hepatocytes secrete approximately 900 milliliters of bile daily. This high secretory capacity is supported by abundant cellular apparatus including rough and smooth endoplasmic reticulum, Golgi apparatus, peroxisomes, and mitochondria. These organelles provide the energy and synthetic machinery necessary for continuous bile production and other metabolic functions.

Histologia do Fígado

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