Liver Flashcards
what ducts converge to form the “common bile duct” and where do they come from?
gallbladder- cystic duct
liver- left and right hepatic duct
pancreas- pancreatic duct
how is the liver divided into lobes?
Divided into 2 large lobes (left and right) and 2 smaller lobes (caudate and quadrate)
what is the dual blood supply of the liver?
Has dual blood supply consisting of venous (portal) supply through the hepatic portal vein and an arterial supply through the hepatic artery
hepatic Portal supply carries ______ absorbed in the intestine, ______ from spleen, and ________ from the pancreas
nutrients and toxic materials- intestine
blood cells- spleen
insulin and glucagon- pancreas
the “end stage of liver disease”
cirrhosis
what organs drain into the portal vein?
spleen, stomach, pancreas and small bowel
the liver stores ____ mL of blood which can be shifted into the circulation during ________ and _____
450
hypovolemia and shock
In right sided heart failure, the pressure in the _____ increases and causes …
vena cava
…a back up of blood which accumulates in the liver
what are the lobules and sinusoids of the liver?
Lobules are the functional units of the liver (not to be confused with the “lobes” of the liver!!!)- within these are the hepatocytes
Sinusoids are channels in the liver and provide for exchange of substances btwn blood and liver cells;
sinusoids are lined with…
lined with typical capillary epithelial cells and Kupffer cells
what are kupffer cells?
Kupffer cells are large macrophages that phagocytize old blood cells, bacteria (especially enteric bacilli from intestines), and foreign material
sinusoids are where ____ flows through, canaliculis are where ____ flows through
sinusoids: blood
canaliculis: bile
what make up the hepatobiliary tree?
intrahepatic (inside liver) and extrahepatic (outside liver) bile ducts.. they unit to form the common bile duct
pancreatic bile duct joins the common bile duct at …
the ampulla of vater …which empties into the duodenum through the duodenum papilla
what does the sphincter of oddi do?
regulars flow of bile into duodenum (when clsoed bile will go back up into gallbladder)
what can cause obstructions in the bile duct? which is the worse one to have an obstruction in?
sludge and stones
- common bile b/c it backs up all routes
what drug would cause spasms of the sphincter of oddi?
morphine - don’t give as pain management to someone with possible gallbladder enlargement as itll cause backing up and more engorgement of gallbladder
3 main metabolic functions of the liver?
- carb metabolism
- lipid metabolism
- protein synthesis and conversion of NH3 (ammonia) to urea
carb metabolism in the liver (2 parts)
Stores excess glucose as glycogen and synthesizes glucose from amino acids
Converts excess carbs to triglycerides for storage in adipose tissue
lipid metabolism in the liver (3 parts)
Oxidation of free fatty acids to ketoacids
Synthesis of cholesterol, phospholipids, and lipoproteins
Formation of triglycerides from carbs and proteins
what happens when we break up triGs?
break up TriGs into glycerol and fatty acids— end product acetylCoA - citric acid cycle = energy
what does the liver produce proteins for?
some for its own needs, some to be exported for other parts of the body to use
what protein synthesized by the liver is of particular importance?
Albumin : contribution to plasma colloidal osmotic pressure and to the binding and transport of hormones, fatty acids, and bilirubin
*overall: albumin helps maintain homeostasis of oncotic pressures. low albumin = ascites b/c fluid SHIFTS out of plasma
protein synthesis and degradation involves what two parts?
transamination and deamination
transamination
NH2 (amine group) is transferred to an acceptor substance (making proteins)
deamination
removal of amino group from amino acids (proteins) and conversion of amino acids to ketoacids and ammonia (NH3)- which is bad. (breakdown of proteins) - excrete as urea
low albumin likely means …
chronic liver issue (really any chronic disease but likely a liver issue)
what can high NH3 levels cause? txt for this?
high NH3 levels = altered mental status (messes with neurons), confused, can seem drunk.
-May have asterixis (“liver flap” - you have flex hand and it begins to pulse)
txt : lactulose- makes you poop (binds NH3 and gets it out of the system)
3 functions of the liver, are the separate or dependent on each other?
dependent
what is the first pass effect in regards to drugs?
Once the medication/drug/toxin enters into the liver, it is degraded until a much smaller amount of the bioavailable drug actually is passed to the systemic circulation.
what is bile made of?
Made of water, bile salts, bilirubin, cholesterol, and other by-products
what is secretion of bile essential for?
digestion (emulsification): fats
absorption: fats and vitamins from intestine
____ are the most important component of bile for digestion
bile salts!
what “path” do bile salts take?
Bile salts travel the circuit of intestine–> portal circulation in distal ileum –> liver 18 times before it meets its final resting place (kidneys as urine or in stool)
what is the recirculation of bile called?
enterohepatic circulation
what gives bile its yellow/green color?
bilirubin
also give stool and urine their color
where does bilirubin come from ?
RBC –> Hgb broken down –> unconjugated (non-watersoluble) bilirubin –> attaches to albumin for transport –> transformed into conjugated (water soluble) in the hepatocytes –> secreted into bile and secreted into small intestine –> half is converted to urobilinogen
where does urobilinogen go on to be absorbed ?
portal circulation, kidneys (rarely) or excreted in stool
most is reabsorbed back through portal circulation and excreted in bile
abnormal levels of unconjugated or conjugated… where would these indicate an issue in regards to the liver?
prehepatic issue- unconj
hepatic issue- conj
direct and indirect/free bilirubin are the same as …
direct: conjugated
indirect/free: unconjugated
what would increased direct or indirect bilirubin indicate?
increased Indirect bili : think increased production of bili, decreased uptake of bili by liver, or decreased conjugation of bili by the liver
increased Direct bili: think decreased secretion and obstruction
total serum bilirum (direct + indirect) is normall what level?
0.1-1.2 mg/dL
what is jaundice and at what levels of bilirubin will you notice it?
Yellow discoloration of skin and deep tissues resulting from abnormally high levels of bili in blood (b/c of destruction of RBCs)
You can notice jaundice around total bili levels of 2-2.5 mg/dL
(gardner said some people it may have to be over 3 to see)
if you dont notice jaundice of the skin, where else might you see it?
sclera of eyes, mucus membranes
3 possible causes of jaundice
prehepatic: excessive RBC destruction
intrahepatic:
posthepatic: osbtruction of bili-flow
most common cause of prehepatic jaundice? what level will be elevated
hemolytic disease of newborn
unconjugated/indirect will be elevated
causes of intrahepatic jaundice?
Decreased bili uptake by the liver
Decreased conjugation of bili
Probable issues with secretion of bili from liver
other possibles (may not be pertinent to know)
- -Drug-induced cholestasis
- -Hepatocellular liver damage
- -Hepatitis, cirrhosis, liver CA
cause of posthepatic jaundice? which level will be elevated?
some kind of obstruction from tumor or stone (cholelithiasis)
direct/conjugated will be elevated
normal levels of direct/conjugated and indirect/unconjugated
direct: 0.1-0.5
indirect: 0.1-0.7
perhepatic jaundice (usually of hemolysis of newborn): how does it present?
Typical presentation: mild jaundice, elevated unconjugated bili, stools are normal color, no bili in the urine
mild unconjugated hyperbilirubinemia is common in the first _____ of life.. what to txt?
2 weeks
get then eating/drinking regularly and it should go away
intrahepatice/hepatocellular jaundice is caused by…
disorders that effect livers ability to remove bili from the blood or conjugate it … bili then cant be eliminated in bile;
can also affect ability to secrete bili from the liver
presentation of intrahepatic jaundice (signs and labs)
- conjugated AND/OR unconjugated bili levels can be elevated
- dark urine
- serum “alk phos” is slightly elevated
- mild jaundice
what is alk phose?
Alkaline phosphatase is an enzyme present in the bile duct epithelium and canalicular membrane of hepatocytes
the cells within bile duct send this out when its obstructed (can be gallstones, malignancies)
posthepatic jaundice is caused by what?
Occurs when bile flow is obstructed between the liver and the intestine; obstruction will be located somewhere btwn the junction of the right or left hepatic duct and the point where the bile duct opens into the intestine
common causes of posthepatic jaundice
strictures of bile duct, gallstones, tumors of bile duct or pancreas
common presentation of posthepatic jaundice
elevated conjugated bili
- stools are clay colored, urine is dark
- alk phos is very high
- aminotransferases increase ( AST/ALT liver enzymes- elevated = liver injury)
what is cholestasis?
Impaired bile formation and bile flow which leads to accumulation of bile pigment in the parenchymal tissues of the liver
causes accumulation of bilirubin, cholesterol, and bile acids in the blood
causes of cholestasis? (5)
Can be caused by intrahepatic or posthepatic issues:
- primary biliary cirrhosis
- primary sclerosing cholangitis (disease of large bile ducts)
- cholelithiasis
- common duct strictures
- obstructing neoplasms
cholestasis: presentation (PE and labs) (4)
pruritis (elevated plasma bile acids. bile in skin = irritation) Skin xanthomas (fatty deposits on eyelids) Elevated alk phos (b/c obstruction at some level) Nutritional deficiencies: vit A, D, and K
what are AST and ALT?
Alanine aminotransferase (ALT)-liver specific Aspartate aminotransferase (AST)-derived from organs other than the liver - used for liver "function" tests : aka to see how much of liver is injured
when will you see a rise in AST/ALT?
In liver damage, you typically see a rise in both values.
EXCEPT in: Liver damage d/t alcoholism:
liver damage from alcohol will usually show an AST/ALT ratio of what?
usually see a 2:1 ratio of AST/ALT
true tests of hepatobiliary function are what?
PT, PTT, INR
what is PT? what are the normal levels for it?
Prothrombin time (PT) helps to assess the liver’s ability to synthesize coagulation factors (factors I, II, V, VII, X) PT normal levels 12-13 seconds
when is PT/INR prolonged? (4)
PT /INR prolonged in: Coagulation factor deficiency Vitamin K deficiency Disseminated intravascular coagulation (DIC) Acute Liver disease
what are factor I and II (measured by PT)?
I- fibrinogen
II- prothrombin
coagulation abnormalities associated with advanced liver disease … (2)
- Prolonged PT with lesser prolongation of PTT
2. Thrombocytopenia: secondary to congestive splenomegaly. Alcohol causes suppression of platelet production
albumin assesses liver’s ____ function. albumin levels decrease in what cases?
Albumin: assesses the liver’s synthetic function
(Synthesized by the liver)
Albumin levels decrease in liver dz, inflammatory dz, severe trauma, malnutrition, nephritic syndrome
what are the normal albumin levels?
Albumin normal levels: 3.4 - 4.7
what does alk phos measure? where do you find it?
AP measures hepatic excretory function
Present in the membranes between liver cells and the bile duct
alk phos is released in disorders affecting what? what can it also be indicative of?
and is released by disorders affecting the bile duct (like obstruction), but can also be indicative of cancer with mets to the bone
normal alk phos level
Alkaline phosphatase (AP): 41-133 units/L
normal GGT level
y-glutamyltransferase (GGT): 9 - 85 units/L
what does GGT levels measure?
Along with alk phos, it measures the excretory function of the liver
Thought to function in the transport of amino acids and peptides into liver cells and is a sensitive indicator of hepatobiliary disease
(more of a secondary test)
elevated GGT levels mean what?
Elevated levels are present in alcohol abuse
in what order will you choose labs to draw for suspected liver issues?
start with CBC, CMP, PT/PTT and maybe (if AP elevated and AST/ALT elevated) maybe GGT, then bilirubin last
what liver tests are not included in CMP?
direct and indirect individual levels (total is included)
PT and PTT, INR
