7.1 Liver Structure and Function (Do 2nd Video)

Question 1

Where is albumin produced?

Answer 1

The liver

Question 2

True or false: the liver receives a majority of its blood supply from the hepatic artery

Answer 2

• False
• It receives blood from the hepatic artery and the hepatic portal vein; majority is actually venous!

Question 3

Liver surface anatomy (ribs, quadrants, surfaces etc.)

Answer 3

• Superior surface aligns w/ 5th rib
• Inferior-most tip is 10th rib (makes sense; liver is best organ, gets to use cool #s)
• Sits mostly in RUQ, but also extends into LUQ
• Has a diaphragmatic and visceral surface

Question 4

Which ligament separates the two lobes of the liver? What are the lobes called?

Answer 4

• Separated by falciform ligament (falx = sickle, like Getafix)
• They are called the left and right lobe.

Question 5

What is the functional relevance of the 8 segments of the liver?

Answer 5

• Each has their own blood supply and branch of bile duct
• If we have a cancer/metastasis, we can remove a segment/segments, and the rest of the liver functions normally

Question 6

Which segments of the liver are supplied by the left vs right branches of the hepatic artery proper?

Answer 6

• Left: I to IV
• Right: V to VIII

Question 7

What are the two lobes on the posterior surface of the liver? Where do they sit?

Answer 7

• Quadrate and caudate lobes
• Along the midline of the liver
• Quadrate = lower visceral surface
• Caudate = upper visceral surface

Question 8

Describe the three fissures on the posterior surface of the liver (and the structures that sit in them)

Answer 8

• Right sagittal fissure (IVC superiorly, and gall bladder inferiorly)
• Left sagittal fissure (round ligament and ligamentum venosum; both previously veins before birth)
• Porta hepatis between caudate and quadrate (portal triad)

Question 9

What stops the liver from falling forwards or backwards?

Answer 9

• Held to anterior abdominal wall by the same falciform ligament
• Held to diaphragm by L/R triangular ligaments and coronary ligament

Question 10

Which ligament does the hepatic triad travel through? What is this structure a part of?

Answer 10

• Travels through hepatoduodenoal ligament
• Together w/ hepatogastric ligament, forms lesser omentum

Question 11

True or false: the liver only has sparse lymphatic connections. This is why there’s no lymphatic vessels in the hepatic triad

Answer 11

• False
• It had extensive connections to phrenic, mammary, pericardiac, and many other lymph nodes.
• This is why liver metastases can be so dangerous.

Question 12

The inferior border of the liver’s falciform ligament becomes the…

Answer 12

• Round ligament
• It runs aROUND the inferior lip of the liver

Question 13

The septae between hepatic lobules are continuous with…

Answer 13

The fibrous capsule of the liver

Question 14

Blood drains from portal triads into central veins in the liver through…

Answer 14

Sinusoids

Question 15

What are the boundaries of a hepatic acinus? What do the three zones mean?

Answer 15

• Corners are two central veins and two vertices, forming a diamond shape
• The line between the two triad vertices indicates most oxygenated [zone 1], and the areas nearest the central veins are least oxygenated [zone 3]

Question 16

What are the boundaries of a portal lobule? What does the lobule represent?

Answer 16

• Three corners in a triangle; each a central vein, with triad in centre
• Represents how newly-made bile flows inward from each vein into a triad for the liver’s exocrine function

Question 17

True or false: all hepatocytes have the same organelles

Answer 17

• False
• Varies based on function/oxygenation; RER might mean protein synthesis, SER might mean VLDL production, lysozyme might mean detoxification etc.

Question 18

Describe the canalicular vs sinusoidal hepatocyte membrane surfaces

Answer 18

Canalicular: tight junctions + bile canaliculi
Sinusoidal: microvilli (space of disse)

Question 19

What’s important about the endothelial structure lining hepatic sinusoids?

Answer 19

• No basal lamina, highly fenestrated
• Allows easy interaction of blood components with cells in space of disse + the hepatocytes themselves

Question 20

What are two functions of Kupffer cells? How does this affect their distribution?

Answer 20

1. Breakdown of worn out RBCs
2. Clearing foreign debris

More common in periportal space (new blood) than centrolobular (pre-filtered)

Question 21

List all the functions of the liver

Answer 21

• Secretes bile (and therefore cholesterol/bilirubin)
• Detoxification
• Metabolism (glyconeogenesis, lipogenesis, gluconeogenesis)
• Synthesises plasma proteins (e.g. albumin)