06b: Liver, GP Histo and Hepatic Transport Flashcards by Nuna H

Liver: The perisinusoidal space, aka space of (X), lies between which structures?

X = Disse

Endothelial cells and hepatocytes

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(Central/sublobular/collecting) veins are supported by prominent sheath of connective tissue.

Sublobular and collecting

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Sinusoids drain into (X), which drain into (Y), which drain into (Z).

X = central vein
Y = sublobular vein
Z = collecting vein

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Collecting veins drain into (X), which drain into (Y), which drain into (Z).

X = hepatic veins
Y = IVC
Z = RA

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T/F: epithelium of gallbladder is composed of only one type of cell, bearing luminal cilia.

False - that cell type bears microvilli

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Which tissue layer(s) are missing in gallbladder?

Muscularis mucosae and submucosa

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The (X) cells of the pancreas have the same staining properties as (Y) duct cells of pancreas. Thus, these cells are distinguished based on location.

X = centroacinar
Y = intercalated ducts

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Most, about (X)% of blood to liver is carried by (Y). Which structure(s) carry the rest?

X = 75;
Y = portal vein

25% via hepatic artery

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The first capillary bed in the hepatic portal system is (X). The second is (Y).

X = GI capillary bed
Y = liver sinusoids

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The sinusoids in liver are receiving (oxygenated/deoxygenated) blood from which vessel(s)?

Mixed;

Terminal branches from portal vein and hepatic artery

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Strong fibroelastic hepatic capsule is called (X) and is covered by (Y) tissue where it faces peritoneal cavity.

X = Glisson's capsule
Y = mesothelium

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The hepatocyte itself has (endocrine/exocrine) function and which cellular domains?

Both;

apical and basal

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The (X) domain of hepatocyte faces perisinusoidal space (Disse). Function of this surface is:

X = basal

Absorption of substances from blood
Secretion of protein into blood

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The (X) domain of hepatocyte is firmly attached to (Y), forming border of:

X = apical
Y = adjacent hepatocyte

Bile canaliculus

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Bile canaliculi are sealed off by (X) formed between which cells?

X = zonula occludens (tight junctions)

hepatocytes

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Bile canaliculi join to form (X), which then carry bile to (Y).

X = short bile ductules (canals of Hering)
Y = large bile ducts

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The liver lobes are further subdivided into:

Lobules

2. Acini

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List the three functional/structural units of the liver and the “shapes” they each depict.

Classic liver lobule (hexagon)
Portal lobule (triangle)
Hepatic acinus (diamond)

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The classic liver lobule has (X) shape and is centered on (Y).

X = hexagon
Y = central vein

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In (X) structural unit of liver, which structure(s) make up the corners of the hexagon?

X = classic liver lobule

Portal triads

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The classic liver lobule is structurally defined by flow of (X) to/from:

X = blood;

To central vein from sinusoids

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The liver portal lobule has (X) shape and is centered on (Y).

X = triangular
Y = bile duct (within portal triad)

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In (X) structural unit of liver, which structure(s) make up the corners of the triangle?

X = portal lobule

Central veins

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The liver portal lobule is structurally defined by flow of (X) to/from:

X = bile

From surrounding hepatocyte into bile duct

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Hepatic acinus has (X) shape and is centered on (Y).

``` X = diamond Y = terminal portal veins ```

In (X) structural unit of liver, which structure(s) make up the corners of the diamond?

X = hepatic acinus 2 Central veins and 2 portal triads

Zone 1 of liver's hepatic acinus is close to (X) structure, thus receiving blood that's (most/least)-rich in oxygen/nutrients and toxins.

X = sinusoids; | Most

Zone 3 of liver's hepatic acinus is close to (X) structure, thus receiving blood that's (most/least)-rich in oxygen/nutrients and toxins.

X = central vein | Least

The architecture and cell processes of liver: designed to transport substances from (X), across (Y), and into the cell.

``` X = sinusoidal blood Y = perisinusoidal space (of Disse) and basolateral membrane ```

The architecture and cell processes of liver: transported substances within hepatocyte undergo modification prior to excretion across (X), and into (Y).

``` X = apical plasma membrane Y = bile canaliculus (biliary system) ```

The ABC, aka (X) family of transporters are important for driving (Y) processes in liver.

``` X = ATP-binding cassette Y = transport (uptake and excretion) ```

Liver plays major role in synthesis of (X) de novo from acetate.

X = FAs and cholesterol

T/F: Most plasma proteins are made in the liver.

True

Following synthesis of a plasma protein, such as albumin, (X) cells secrete it into (Y).

``` X = hepatocytes Y = perisinusoidal space (of Disse) ```

List some key substances that are secreted by hepatocyte into the bile canaliculus.

1. Bile salts 2. Cholesterol 3. Phospholipids 4. Bilirubin (conjugated, BRDG)

ABC B-11 is important for (X) process in liver.

X = transport of conjugated bile salts from hepatocyte to bile canaliculus

ABC B-4 is important for (X) process in liver.

X = transport of phosphotydylcholine (PC) from hepatocyte to bile canaliculus

ABC G-5/8 is important for (X) process in liver.

X = transport of sterols (esp cholesterol) from hepatocyte to bile canaliculus

ABC G-5/8 is important for (X) process in gut.

X = transport of sterols (esp cholesterol) from enterocyte to intestinal lumen

ABC C-2 is important for (X) process in gut.

X = transport of bilirubin digluciride (BRDG) from hepatocyte to bile canaliculus

Most, 90%, of bile is composed of which substances?

1. Bile acids (Na salt) 2. Phospholipids 3. Cholesterol

Cholesterol solubility is about 1 million times greater in (X) than in water.

X = bile

T/F: The great majority of bile is composed of cholesterol.

False - bile acids

Bile has significant amount of (phospholipid/protein/bilirubin).

Phospholipids (but the other two also present)

Primary bile acids are synthesized by (X) process in (Y) location. What's the enzyme responsible?

``` X = conjugation of cholesterol Y = liver ``` 7-alpha hydroxylase (rate-limiting)

During synthesis of bile acids in liver, it's important to conjugate their (X) group with (Y) to (raise/lower) (Z). This prevents their precipitation in the duodenum.

X = OH (of carboxyl groups) Y = glycine or taurine Lower; Z = pKa

Secondary bile acids are synthesized by (X) process in (Y) location. What's the cell type responsible?

``` X = dehydroxylation and deconjugation; Y = colon ``` Bacteria

(Cholic/deoxycholic) acid is a (primary/secondary) bile salt.

Cholic (primary); deoxycholic (secondary)

(Cholic/lithocholic/deoxycholic) acid is a (primary/secondary) bile salt that's insoluble, thus mostly excreted instead of recycled.

Lithocholic; | Secondary

Most, over (X)%, of bile salts are reabsorbed in which specific location of GI tract? Via which mechanism/channel/transporter?

X = 95 Ileum; IBAT (Ileal Bile Acid transporter)

Following reabsorbtion into (X) cell in ileum, bile salt exits into (Y). What's its destination? It travels (free/bound).

``` X = enterocyte; Y = portal blood ``` Hepatocyte; Bound to albumin

The Na-Taurocholate-Cotransport Protein (NTCP) is found on (X) cells and responsible for (uptake/secretion) of (Y).

X = hepatocytes; Uptake Y = bile salts

T/F: Cholesterol sources are exclusively synthesis by liver and ingestion from diet.

False - some peripheral tissues synthesize cholesterol

T/F: Non-hepatic cholesterol is also delivered to the liver.

True

T/F: The liver handles non-hepatic cholesterol in the same way as its own (synthesized) cholesterol.

True

The bile sale pool recycles about (X) times a day.

X = 8

T/F: Liver doesn't need to synthesize any bile salts on a regular basis.

False - synthesizes small amount (0.4g) lost in feces daily

A mixed micelle is formed on (luminal/basal) side of (X) cell/structure, following transport of which 3 key components?

Luminal; Bile canalicular membrane Bile salt, PC (phospholipid), cholesterol

Gallstones in normal-weight patient likely due to issues with (high/low) (X) secretion.

Low | X = rate of bile salt

Gallstones in over-weight patient likely due to issues with (X) secretion.

High (double); | X = cholesterol

In both obese/non-obese patients, (X) is the event that actually forms the gallstones.

X = precipitation of cholesterol

Albumin generally binds (X) molecules of FAs, though its max capacity is (Y).

``` X = 1-2 Y = 10-15 ```

FA bound to albumin in excess of (X) ratio are quickly transferred to (Y). What's their eventual fate?

``` X = 1:1 Y = hepatocyte membrane ``` Flip to cytoplasmic surface, removed by FABP, and enter cell FA pool

When albumin is synthesized in (X) location, it's (free/bound).

X = liver; | Free

The major apoprotein of HDL, (X), undergoes synthesis in (Y). Which major modification produces the nascent HDL particle?

``` X = Apo-A1; Y = liver ``` 10-14 Phospholipids (especially PC) added (to 2 A1 molecules)

Apoprotein B100, just following its (transcription/translation/translocation), has two possible fates, depending on (X). What are they?

Translocation (into ER lumen); X = availability of lipid substrate; 1. Degradation 2. VLDL synthesis

Apo-B1 is combined with (X) to form nascent (LDL/HDL/VLDL/chylomicron).

X = phospholipids and cholesterol; VLDL