Liver Anatomy Flashcards
What is a liver lobule composed of?
- Portal triad
- Sinusoid
- Central vein
- Hepatocytes- produce bile
- Kupffer cells- phagocytosis and detoxification
- Bile canaliculi- drain bile
What is the functional unit of the Liver?
Liver lobule
What is the functional cell of liver?
Hepatocyte
Portal triad
Portal vein, hepatic artery, bile duct.
Extrahepatic portal triad
Proper hepatic artery, main portal vein, cbd/chd
What is ampulla of vater?
An opening of the second part is of the duodenum, near the pancreatic head
Explain the pathway of bile
Hepatocytes»_space; canaliculi»_space; interlobar duct»_space; R & L hepatic duct»_space; Common hepatic duct»_space; joins cystic duct to become»_space; CBD
What is bile made of?
Bile salts, bilirubin, amino acids, cholesterol and water
What is cholecystokinin (CCK)
Hormone produced by the upper intestine and released when eating fatty food. It makes the GB contract and release bile.
Liver/ Blood reservoir
1500 ml of body’s vol flow rate/min through liver
1000-1100 ml/min of blood flows through the portal veins
350-400 ml/min through hepatic artery
The liver has a capacity to enlarge and store 200-400 ml of blood
Detoxification function of Liver
The liver converts foreign molecules and hormones to safer compounds that are not as toxic.
Ex: when a.a. Are burned for energy they leave behind the nitrogenous waste that is converted to urea by the liver.
ATP & ADP (forms of energy) is converted to ammonia in the urine.
Lymph formation by the liver
The liver produces 1/3-1/2 of the body’s lymph fluid
Acute and chronic hepatitis
May be mild or severe.
A, B, C, D, E
These account for 95% of all hepatitis cases
What are the pathological features of viral hepatitis?
- Liver cell damage
- Hepatomegaly
- Cellular degeneration and necrosis
- Regeneration
Clinical features of hepatitis
Headache Nausea and vomiting Fatigue Jaundice, dark urine RUQ Tenderness Symptoms usually resolve completely in less than 6 weeks with bed rest
What is interferon
An into-viral drug used to treat HBV (hepatitis B virus)
What are the lab values for hepatitis?
⬆️ ALT (SGPT) ⬆️ AST (SGOT) ⬆️ bilirubin ⬆️ WBC ⬆️ PTT Dark urine
What is the sonographic appearance of acute hepatitis?
Hepatomegaly
Parenchyma becomes hypoechoic
Vessel walls become more echogenic
Looks like starry sky liver
Chronic hepatitis
HBV, HCV, Alcohol
3-6 months of inflammation
What is the sonographic appearance of chronic hepatitis?
Small echogenic liver
Leads to cirrhosis- permanent damage
Thickened GB wall seen in both acute and chronic hep.
What is cirrhosis?
A progressive, irreversible disease of liver.
Liver cells degenerate faster than they can generate.
Grows over scar tissue
Normal architecture is destroyed
What is cirrhosis etiology?
- Alcoholism
- HCV
- Biliary malfunction
- Drugs, toxins and infection
What are the clinical signs and symptoms of cirrhosis?
>Early stage may be asymptomatic. >Later stage: scar tissue (fibrosis), causing: Exhaustion Loss of appetite Nausea Weakness Weight loss Abdominal pain Fatigue >Final stage: ascites and portal hypertension
Lab values of cirrhosis
⬇️ albumin
⬆️ liver enzymes (SGPT, SGOT)
⬆️ indirect bilirubin
⬆️ PTT
What are the 3 stages of cirrhosis?
- Tissue necrosis
- Tissue regeneration
- Fibrosis
*When fibrosis overwhelms regeneration, the liver will become atrophic and eventually fails.
What is the sonographic appearance of early cirrhosis (stage 1)
Hypoechoic
Hepatomegaly
What is the sonographic appearance graphic appearance of stage 2 cirrhosis?
Increased liver echogenicity
Atrophy
Ascites
Irregular shape of liver, surface nodularity
With alcoholic cirrhosis, what kind of bilirubin is increased?
Indirect bilirubin, Unconjugated, fat soluble.
With biliary cirrhosis what kind of bilirubin is increased?
Direct bilirubin, conjugated, water soluble
What is the most common cause of intrahepatic portal hypertension?
Cirrhosis. Occurring in 90-95% of cases
What causes portal hypertension?
Cirrhosis Portal and splenic vein thrombosis Budd chiari syndrome Sepsis- blood infection Pancreatitis
Intrahepatic portal hypertension causes
Cirrhosis
Portal-splenic vein thrombosis
Budd chiari syndrome
Extrahepatic portal hypertension causes
Sepsis
Pancreatitis
What will portal hypertension cause?
- Gastroesophageal varices: resulting in GI bleed
- Caput Medusae: varicose veins radiating from the umbilicus
- Splenomegaly, SMV, IMV, hemorrhoidal veins will dilate
- Ascites
- Hepatic failure
What is T.I.P.S.?
Trans-Jugular Intrahepatic Porto-Systemic Shunt
*Used to treat portal hypertension
What is the sonographic appearance of portal hypertension?
Depending on degree of venous obstruction:
- Abnormal portal flow
- Non-visualization of hepatic veins
- Splenomegaly >12 cm
- Recanalized ligamentum teres
- PV diameter > 13mm
- Portal venous pressure is > 30mmhg
- Caudate lobe enlargement
What is hepatic encephalopathy?
Altered mental states as a result of high toxins in the blood
What is non-alcoholic steatohepatitis?
Serious form of fatty liver found in some people with non-alcoholic fatty liver disease causing inflammation and scarring in liver. At its most severe state it can progress to liver failure.
What is fulminant hepatic failure?
Acute liver failure, causing excessive bleeding and increased pressure in the brain.
Signs and symptoms of Acute Liver Failure
Jaundice RUQ pain Nausea/vomiting Difficulty concentrating Disorientation or confusion Sleepiness
What are the causes of acute liver failure?
When liver cells are damaged and no longer able to function.
Acetaminophen overdose *most common cause in U.S.
Antibiotics, anti-inflammatory drugs, anticonvulsants
Herbal supplements, such as kava, ephedra, skullcap, pennyroyal.
Hepatitis and other viruses
Toxins such as poisonous wild mushroom
Autoimmune disease
Budd chiari syndrome
Metabolic disease such as Wilson’s disease, acute fatty liver of pregnancy
Cancer
Some have no apparent causes
What is should the gallbladder wall measure under ultrasound?
Less than 3 mm in thickness
What is secretin?
Hormone that stimulates the production of bile
What are the anatomical components of the gallbladder?
Neck aka infundibulum or hartman’s pouch
Body
Fundus
What is the size of the gallbladder?
Length: 10 cm or less
AP: no more than 4 cm
Wall should be less than 3 mm in thickness
When is the gallbladder considered contracted?
When measuring less than 2 cm in diameter after appropriate fasting
What is hydropic gallbladder?
When the GB is larger than normal
> 4 cm AP diameter
Over distended
What are the gallbladder variants?
Junctional folds- fold between neck and body
Phrygian cap- fold between body and fundus
What are Heister Valves?
Valves located in the cystic duct that regulate flow in and out of GB.
Keep cystic duct from collapsing or folding.
May shadow and should not be confused for stone
What is the size of the intrahepatic bile ducts?
< 2 mm
Bile duct measurements
CHD 5mm or less
CBD 5 mm or less and 1 mm for each decade of life after the 5th decade
What is the proper form of measuring CBD?
Distally from inner wall to inner wall
What are the clinical signs and symptoms of acute cholecystitis?
Positive murphy's sign Fever Increased WBC Increased bilirubin Increased ALP
What are the clinical signs and symptoms of chronic cholecystitis?
Possible increase in WBC
Possible normal lab values
Not as painful as acute
What are the song graphic features of acute cholecystitis?
Diffusedly thickened GB wall > 3 mm (striated wall appearance)
Pericholecystic fluid/subserosal edema around GB (halo sign)
Hydropic/cholecystomegaly
Stones
Hypervascularity of the wall
Possible choledocholithiasis
Sonographic features of chronic cholecystitis?
Diffuse wall thickening Contracted GB after NPO Non-visualization due to contraction Stone shadowing WES sign (in long) Double Arc sign (in trv) Post wall will be shadowed out
What is cholangitis?
Inflamed bile duct or entire biliary tree
Etiology of cholangitis
Cholelithiasis
Cholecystitis
Sonographic appearance of cholangitis
Dilated intrahepatic and extrahepatic ducts
What complication can arise from acute cholecystitis?
Stone obstructs cystic duct, in result obstructing venous drainage and inflammation of GB wall with variable degree of necrosis and infection
What causes sludge in GB?
Fasting
Obstruction may lead to acute cholecystitis
What is hepatization of GB?
Sludge that totally fills the gallbladder so that its contents become isle choir with liver
What is timer active sludge?
Sludge is not mobile, rounded, non-shadowing, medium level echogenic masses in the dependent portion of the gallbladder
What is hemobilia?
Bleeding into the biliary tree associated with hepatic biopsy, rupture of hepatic artery and blunt abdominal trauma
What is hydrops of the gallbladder?
Distended, non-inflamed gallbladder due to total obstruction of the cystic duct
Trapped bile is re absorbed and GB is filled with a clear mucinous secretion derived from the mucosa
Signs and symptoms of hydrops of the GB
Asymptomatic
May present as a palpable RUQ mass
The diagnosis should be suspected on ultrasound when an obstructing stone is noted in an enlarged but non-tender GB
What kind of gallstones are there?
80% of cholesterol
Black pigment stones
Brown pigment stones
When do cholesterol stone form?
When bile contains too much cholesterol
Too much bilirubin or not enough bile salts or lecithine
When the GB does not empty often
What causes black pigment stones?
Too much bilirubin in bile
Associated with hemolytic anemia such as thalacemia, sickle cell anemia and malaria
Cirrhosis of liver
They are black and hard
What causes brown stones?
Infection ascending from duodenum into bile duct or GB
Bacteria alters bilirubin pigment and combines w fat in bile to form gallstone
They are softer than black pugment gallstones
Who is at risk for gallstones?
Those who prolong fasting, dieting, fat free diets or fluid diets. More common in women than men 4:1 Increased prevalence with age (3,4th decade) Overweight Individuals Pregnancy due to rise in cholesterol Hormone therapy/birth control Crohn's disease Cystic fibrosis of liver
What are the symptoms of gallstones?
Biliary colic Pain under Rt shoulder- may radiate to the back between shoulder blades Nausea vomiting Abdominal bloating Intolerance of fatty food Belching Flatulence Indigestion
