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N542 Physiology > Liver > Flashcards

Flashcards in Liver Deck (21)
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0
Q

What does the gall bladder do?

A

Gallbladder stores bile and sucks water out to concentrate all the bile to emulsify fat
CCK is the hormone of the gallbladder

1
Q

What is in the gall bladder besides bile?

A

other “stuff” from the liver, like bilirubin

2
Q

What is the structure of a liver lobule?

A

Hexagon with portal triad at each corner and central vein in the center
Contains Kupffer cells (macrophages, live forever)

3
Q

What is the portal triad made up of? Which way do the vessels flow?

A

Hepatic portal vein (80%) - drains to central vein
Hepatic artery (20%)
Bile duct
Lymphatic vessel - drains away from central vein

4
Q

What is the anatomy of the liver like, how does this relate to its function?

A

The liver is soft and expandable like a sponge and half the mass is blood, the reticular fibers are weak, blood spends 30 sec here (3 sec in other organs). To be filtered completely, low pressure in the portal vein (9 mmHg, from body to liver), even lower pressure in hepatic vein (0mmHg, from liver to vena cava), overall low resistance to blood flow

5
Q

Why does the liver have sinusoidal capillaries?

A

These big holes allow for larger particles to pass through the capillaries. This would cause edema in other parts of the body but the hydrostatic pressure keeps this from happening.
Note: the hepatocytes that line the capillaries have microvilli to increase surface area to increase absorption, the capillaries are also lined with endothelial cells and Kupffer cells

6
Q

What are bile canaliculi?

A

Gaps between hepatocytes that form a small canal for fluid to run between cells, until it gets to the bile ductule and finally the bile duct. The TIGHT junction (zona occludens) surrounding the bile canaliculi makes it water tight so that the fluid can’t ooze through back into the blood.

7
Q

What do Kupffer cells do?

A

Kupffer cells eat the bacteria so that it doesn’t go to systemic circulation, they detoxify hepatocytes

8
Q

What are the metabolic functions of the liver?

A

Carb, protein, fat metabolism, and other metabolism

9
Q

How does the liver help with carbohydrate metabolism?

A

Stores large amounts of glycogen, conversion of galactose and fructose into glucose, gluconeogenesis, and formation of compounds from intermediate products. This is how the liver acts as a buffer in the control of blood sugar.

10
Q

How does the liver help with protein metabolism?

A

Deamination of amino acids, formation of urea for removal of ammonia from body fluids, formation of plasma proteins, converts and synthesizes other amino acids

11
Q

How does the liver help with fat metabolism?

A

Oxidation of fatty acids to supply energy to the body (the liver dumps ketone bodies so the rest of the body can break down fatty acids.. so the liver basically does the first step of fat metabolism)
Synthesis of cholesterol, phospholipids, and lipoproteins
Synthesis of fat from proteins and carbs

12
Q

Besides carb, protein, and fat metabolism, what are the other metabolic functions of the liver?

A

Stores vitamins (A,D,B12), stores iron as Ferritin (can release or hold on to iron based on the body’s needs, considered a blood iron buffer)
Forms blood substances used in coagulation (prothrombin, fibrinogen, factor 7)
Removes/excretes drugs, hormones, and other substances (like calcium, penicillin, thyroxine, estrogen)

13
Q

What is unique about a hepatocyte when looking at it microscopically?

A

Hepatocytes are busy cells! They have large, light stained nucleus (making a lot of RNA to make a lot of protein), has a lot of RER (to package and send out the plasma proteins), lots of fat in the cell (makes cholesterol)

14
Q

What is unique about the lymph in the liver?

A

Lymph doesn’t usually have a lot of protein, but in the liver it contains just as much protein as the blood does. About half the lymph you make everyday is in the liver

15
Q

How does the perilobular region of the hepatic sinusoid differ from the centrolobular region (toward the central vein)?

A

Going from perilobular to centrolobular, the oxygen content falls, making these centrolobular cells more hypoxic and more likely to be injured

16
Q

How is bile salt made and how much of it gets reused?

A

Bile salts made by cholesterol, 90% reabsorbed in the intestines and recirculated, 10% synthesized bile in the SER and released into the ducts

17
Q

What do bile and bilirubin have in common?

A

The bili, they both travel through the biliary tract, otherwise they are very different

18
Q

How do size, density, TAGs, location differ between chylomicrons, VLDL, LDL, and HDL?

A

Chylomicrons: biggest, least dense, most TAGs, comes from GI to the blood (broken down the least)
VLDL: second biggest, second most TAG, from liver to blood
LDL: second smallest, from blood to body and liver
HDL: smallest, most dense, least TAGs, from body to liver

19
Q

What happens to LDL particle when it gets to the cell?

A

LDL particle binds to LDL receptor, receptor is recycled to pick up more LDL and LDL is endocytosed, lysosome breaks it down so the contents are available to the cell

20
Q

When a RBC is destroyed, how is it broken down and excreted?

A

It first disassociates to heme and globin. The iron part of heme goes to iron pool, the biliverdin (green bruise) reduces quickly to unconjugated bilirubin (not water soluble) and is released by macrophages into the plasma. This binds with albumin, transporting it to the liver, to get conjugated by sticking glucuronic acid on it (water soluble). It is then dumped, as urobilogen, in feces and 5% in urine