Metabolism 11 (Exam 4) Flashcards

1
Q

What is the liver often called?

A

The body’s major biochemical factory

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2
Q

Why are sharks buyoant?

A

The liver makes lots of LDLs for them!

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3
Q

How do hepatocytes access venous blood?

A

Portal vein

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4
Q

How do hepatocytes access arterial blood?

A

Hepatic artery

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5
Q

What is the capillary network in the liver called? What does it permit?

A

Sinusoids

Permits exchange between the hepatocytes and blood

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6
Q

Once blood drains from the liver, where does it go?

A

It drains into the hepatic vein which connects to the inferior vena cava

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7
Q

What is the primary cell of the liver? What is its function?

A

Hepatocyte

It has quite high metabolic and secretory functions that are complemented by phagocytic activity in resident macrophages

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8
Q

What % of total body weight does the liver make up?

A

2%

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9
Q

What is the liver’s functional unit

A

lobule

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10
Q

What is a lobule?

A

cylindrical structure several mm in length and diameter

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11
Q

How many lobules are in the liver?

A

50,000-100,000

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12
Q

The individual bile ducts converge to form what? What does that do?

A

Hepatic duct

The hepatic duct delivers bile to the duodenum

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13
Q

Explain liver blood flow starting with the portal vein

A

Portal vein –> small portal venules –> flat branching hepatic sinusoids (between the plates) –> central vein

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14
Q

Where are hepatic arterioles present?

A

In the interlobular septa

They frequently terminate into hepatic sinusoids

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15
Q

What are the three cell types of the liver?

A

Hepatocytes, Liver sinusoidal endothelial cells, and large kupffer cells

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16
Q

What are the large pores in the liver endothelial lining called? what do they do?

A

Fenestra

Allow plasma proteins to fit through

17
Q

What are the spaces of Disse

A

they are perisinusoidal spaces between the endothelial lining and the hepatic cells

18
Q

What do the spaces of Disse connect to?

A

They connect with lymphatic vessels in the interlobular septa. Excess fluid in these spaces is removed via lymphatics

19
Q

What are kupffer cells also known as?

A

Reticuloendothelial cells

Resident macrophages

20
Q

What do kupferr cells do?

A

Capable of phagocytizing bacteria and foreign matter

21
Q

How fast is liver blood flow from the portal vein into the liver sinusoids?

A

Pretty fast
~1,000 ml/min
Additional 300 ml/min from the hepatic artery
Total is ~27% of CO

22
Q

Explain how the liver has very low vascular resistance even despite the high volume

A

Pressure in the portal vein averages 9 mmHg

Pressure in the hepatic vein from the liver into the vena cava averages 0 mmHg

23
Q

How can the liver function as a blood reservoir?

A

It’s a large, expandable organ
Its normal blood volume is ~450 mL (10% of total blood volume)
High atrium pressure can expand the liver to another 0.5-1 mL of blood

24
Q

How does liver lymph compare to normal lymph?

A

It has 3 times the amount of protein

25
How do the hepatic sinusoids compare to other capillaries in terms of permeability?
the hepatic sinusoids have pores that are very permeable so lymph draining has about 6g of protein/dL (only slightly less than the protein in the plasma)
26
What does the high permeability and flow of the hepatic sinusoids allow?
It allows for about half of all lymph in the body to be generated in the liver
27
What is portal hypertension in small animals?
Elevated pressure within the portal venous system
28
Describe what prehepatic portal hypertension in small animals looks like.
Portal vein obstruction and hepatic arteriovenous fistula | Symptom: Ascites (the accumulation of fluid in the peritoneal cavity)
29
Describe what Intrahepatic portal hypertension in small animals looks like.
Likely fibrosis caused by toxins or infections, AKA cirrhosis
30
Describe what posthepatic portal hypertension in small animals looks like.
Posthepatic causes involve the heart, cranial vena cava, and hepatic veins
31
Partial hepatectomy (excision of the liver) (up to 70%) will result in?
It causes the remaining lobes to enlarge and restore the liver to original size (regeneration) It's pretty rapid, believed to involve the hepatocytes replicating once or twice before re-entering quiescent state