06b: Liver, GP Histo and Hepatic Transport Flashcards
Liver: The perisinusoidal space, aka space of (X), lies between which structures?
X = Disse
Endothelial cells and hepatocytes
(Central/sublobular/collecting) veins are supported by prominent sheath of connective tissue.
Sublobular and collecting
Sinusoids drain into (X), which drain into (Y), which drain into (Z).
X = central vein Y = sublobular vein Z = collecting vein
Collecting veins drain into (X), which drain into (Y), which drain into (Z).
X = hepatic veins Y = IVC Z = RA
T/F: epithelium of gallbladder is composed of only one type of cell, bearing luminal cilia.
False - that cell type bears microvilli
Which tissue layer(s) are missing in gallbladder?
Muscularis mucosae and submucosa
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
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
The first capillary bed in the hepatic portal system is (X). The second is (Y).
X = GI capillary bed Y = liver sinusoids
The sinusoids in liver are receiving (oxygenated/deoxygenated) blood from which vessel(s)?
Mixed;
Terminal branches from portal vein and hepatic artery
Strong fibroelastic hepatic capsule is called (X) and is covered by (Y) tissue where it faces peritoneal cavity.
X = Glisson's capsule Y = mesothelium
The hepatocyte itself has (endocrine/exocrine) function and which cellular domains?
Both;
apical and basal
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
The (X) domain of hepatocyte is firmly attached to (Y), forming border of:
X = apical Y = adjacent hepatocyte
Bile canaliculus
Bile canaliculi are sealed off by (X) formed between which cells?
X = zonula occludens (tight junctions)
hepatocytes
Bile canaliculi join to form (X), which then carry bile to (Y).
X = short bile ductules (canals of Hering) Y = large bile ducts
The liver lobes are further subdivided into:
- Lobules
2. Acini
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)
The classic liver lobule has (X) shape and is centered on (Y).
X = hexagon Y = central vein
In (X) structural unit of liver, which structure(s) make up the corners of the hexagon?
X = classic liver lobule
Portal triads
The classic liver lobule is structurally defined by flow of (X) to/from:
X = blood;
To central vein from sinusoids
The liver portal lobule has (X) shape and is centered on (Y).
X = triangular Y = bile duct (within portal triad)
In (X) structural unit of liver, which structure(s) make up the corners of the triangle?
X = portal lobule
Central veins
The liver portal lobule is structurally defined by flow of (X) to/from:
X = bile
From surrounding hepatocyte into bile duct
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.
- Bile salts
- Cholesterol
- Phospholipids
- 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?
- Bile acids (Na salt)
- Phospholipids
- 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;
- Degradation
- VLDL synthesis
Apo-B1 is combined with (X) to form nascent (LDL/HDL/VLDL/chylomicron).
X = phospholipids and cholesterol;
VLDL