Liver and biliary system Flashcards
Largest gland in our body
Detoxification and elimination body wastes, drugs and other foreign substances
liver
The liver stores:
glycogen, fats, iron, many vitamins
The venous blood coming from the intestine is rich in absorbed ___. But it can also contain various potentially toxic compounds such as product from the bacterial metabolism/degradation or damaged or aged cells. These products 1st enter the hepatic ____ and are carried to the liver. In the liver, they are extensively modified chemically and only after that can these products enter the hepatic veins, which eventually drain into the ___
nutrients
portal vein
inferior vana cava
the functional unit of the liver
Hepatic lobule
Each hepatic lobule is centered around the central vein which drains into the ____
hepatic vein
70% of the surface area of each hepatocyte faces the __, maximizing the exchange between blood and the cells.
sinusoids
are very small ducts in which hypatocytes secrete the product of bile, then they join together to form the large compiled duct
bile canaliculi
the liver absorbs the following from the GI tract:
nutrients
bilirubin
drugs
foreign substances
the liver secretes the following into the duodenum:
bile salts
bilirubin
water, ions
phospholipids
liver products
synthesis plasma protein, albumin, fibrinogen, and additional clotting factors
the largest group of macrophages in the body, responsible for ingesting foreign bodies entering the blood via the GI tract
Kupffer cells
Between the endothelial cells there are large spaces called ____ allowing free exchange of various substances between the hepatocytes and blood plasma. The RBC are the only thing that cant pass through
fenestrations
the metabolism of drug in the small intestine and most importantly in the liver which reduces the amount of drug that’s dilevered to the systemic circulation is called
presystemic elimination
pre-systemic extraction
or first-pass elimination
Some drugs undergo complete 1st pass metaboilism , so therefore they are not administered orally. An example is ___, it is completely metabolized via 1st pass so its admin sublinguallly or transdermally which helps to bypass 1st pass metabolism.
nitroglycerin
The bile in the liver is produced by the liver cells, __
hepatocytes
bile 1st enters the hepatic ___, then flows from the bile ducts, and emerges into the hepatic ducts which are coming from each lobe of the liver. The hepatic ducts then come together to form the ___ duct and then the cystic duct from the gallbladder, it joins the common hepatic duct. The hepatic bile and pancreatic juices pass through the same secretory duct, the hepatopancreatic ampula (ampulla of Vater). Entrance to the duodenum is guarded by the sphincter of __, which is closed most of the time except during the meal. The system of the of the bile duct is referred to as the biliary tree.
cannaniculi
common hepatic
oggi
The biliary tree can be visualized by injecting contrast media from an endoscope channel maneuvered into the sphincter of Oddi, in a procedure known as
endoscopic retrograde cholangiopancreatography (ERCP)
The bile contains various organic components: ___ ___ ___ ___. These components are produced by the hepatocytes and are diluted in the aqueous alkaline fluid which is aided by the bile duct cells.
bile salts, cholesterol, lecithin and bilirubin
____ are derivatives of cholesterol and aid fat digestion through their detergent action (emulsification).
Bile salts
bile salts have both __ soluble hydrophobic portion and also ___ soluble negatively charged hydrophilic portion.
lipid
water
Because negative charges are on the surface of the lipid droplet the droplets repel one another. This helps to successfully digest the fat because it provides additional surface area for pancreatic ___.
lipase
the bile salt absorb fat through the formation of ___
micelles
Another component of bile which is called ___, and also has the water soluble portion and the lipid soluble portion. In a micelles, the lipid soluble portions of the bile salts and ___ they aggregate and the form the lipid hydrophobic core of the micelles, at the same time forming the hydrophilic shell
lecithin
lecithin
The most important compound carried within the hydrophobic core of the micelles include ___
cholesterol
pre-fatty acids
monoglycerides
fat soluble vitamins
Following their participation in fat digestion and absorption, most bile salts are reabsorbed back into the blood by special active transport mechanisms located in the terminal ___. From here bile salts are returned by the hepatic portal system to the liver, which re-secretes them into the bile.
ileum
recycling of bile salts and other components of bile between the small intestine and the liver is called
the enteropatic circulation
Many drugs are deactivated by the liver and excreted into bile; __ recycling can slow the rate of drug elimination
enterohepatic
However it was estimated that from __ grams of bile salt is emptied into the small intestine with each meal. This means that the bile salts they are recycled between the liver and the small intestine at least twice during each meal and they are recycled about 6-8 times per day
3 up to 15
Only about __ g/day of bile is lost in the feces but then liver compensated for this loss
0.2
The most potent choleretic is ___ __
bile salts
Any agent which stimulates bile secretion by the liver is called
choleretic
___ stimulates the production of the alkaline portion of the pancreatic juice by the pancreatic duct cells in order to neutralize the acid in the duodenum.
the secretion also stimulates the bile duct cells in the liver to produce the ___ aqueous portion of bile
Secretin
alkaline
the most powerful signal for gallbladder contraction and also mediates relaxation of the sphincter of Oddi, allowing biliary and pancreatic secretions to enter the duodenum
CCK
a yellow pigment that gives bile its yellow color.
Bilirubin
the action of intestinal bacteria metabolizes bilirubin to the colorless molecule ___.
urobilinogen
About 80% of urobilinogen is metabolized by bacteria and colors feces with the brown pigment ____.
stercobilin
the product of degradation of HEME, the iron contain portion of hemoglobin
bilirubin
The macrophages they release bilirubin into the blood plasma. In the blood plasma its bound to ___ bc bilirubin itself is not very water soluble, so this protein bound form of bilirubin is called the ____ or ___ and sometimes also called indirect bilirubin.
albumin
free bilirubin
unconjugated bilirubin
If bilirubin is produced more rapidly than it can be excreted it accumulates and cause ___
jaundice
Jaundice can be brought about in 3 different way
Pre-hepatic jaundice
The hepatic Jaundice
Post-hepatic jaundice
means the problem occurs before the liver conjugates the bilirubin; is characteristic for the patient with hemolytic anemia
Pre-hepatic jaundice
the problem occurs with the liver itself and its usually a characteristic for various liver diseases such as hepatitis and cancer. In this case, the liver is not able to process not even small amounts of bilirubin
The hepatic Jaundice
occurs when the bile flow is obstructed due to various reasons. The most common cause of biliary obstruction is gallstones in the bile duct. In addition the bile ducts can also become pressed by various tumors, such as the cause with panreatic cancer
Post-hepatic jaundice
Obstruction of bile flow is characterized b:
Dark urine (bilirubinuria), light feces, itching which it thought to be due to the accumulation of bile salts under the skin
refers to the blockage of any duct that carries bile from the liver to the gallbladder or from the gallbladder to the small intestine. This can occur at various levels within the biliary system
- most common cause of gall stones
Biliary obstruction
___ is the primary site for precipitation of concentrated bile constituents into gallstones.
Gallbladder
Theres an active transport of salt, out of the gall bladder into the lumen. With the water following osmotically, it causes ___ times the concentration of organic bile components within the gall bladder
5-10
yellow-green, primarily made of hardened cholesterol, associated with bile supersaturated with cholesterol, account for 80% of gallstones and are more commonly involved in biliary obstruction
Cholesterol stones
mainly composed of calcium bilirubinate. Patients with chronic hemolytic diseases are most at risk of developing this type of gallstone due to high levels of bilirubin excretion.
Pigment stones
two Types of gallstones
Cholesterol stones and pigment stones
- inflammation of gallbladder wall
Cholecystitis
most common complication of gallstones
acute cholecystitis
Acute cholecystitis is usually caused by impaction of a gallstone in the ___ ___. The entrapped bile in the gallbladder causes damage to the gallbladder mucosa and inflammation of the gallbladder wall
cystic duct.
is a complication that occurs when gallstones become displaced to the common bile duct
Its associated with serious complications such as cholangitis-– the bacterial infection of bile ducts or acute pancreatitis
Choledocholithiasis
Most obstructions can be treated with __ or __. Obstructions caused by cancer often have a worse outcome
endoscopy or surgery
Stone in the common bile duct means we are dealing with ____ jaundice and biliary obstruction. The problem is after the liver which means the liver still conjugates the bilirubin normally just that is cannot be excreted in the bile because the bile flow is blocked so it s going to start to leak to the systemic circulation. As a result, we have high levels of conjugated bilirubin plasma bilirubin
post hepatic
___ conjugated plasma bilirubin will result in ___ urobilinogen
High
Low
If we have the fatty meal, the entero-endocrine cells of the small intestine are going to produce a lot of ___, which is the most powerful stimulus for gallbladder contraction. the bile in this case is going to come out and will not have anywhere to go bc we have a gallstone there in the common bile duct. this results in great pain
CCK (cholecystokinin)
