L6 liver Flashcards
what are the functions of the liver
bile production, process blood, detoxes blood, store glycogen, fetus erythrocyte production, synthesis amino acid/lipid/complex carb, synthesis of proteins
liver position and size
inferior to diaphragm and is protected by ribcage, right side, 1.4 kg
what is the bare area
superior, slightly posterior surface, touches diaphragm, not covered by visceral peritoneum
what is falciform ligament
mesentery, separates the two lobes suspends liver from the diaphragm and the anterior body wall
what is the round ligament
ligamentum teres, remnant of umbilical vein
where is lesser omentum
in fissure between L R lobes
what is porta hepatis
contains hepatic artery and hepatic portal vein
what are the segments of the liver
8 segments, clockwise from the caudate lobe, each section has its own branch of portal vein, hepatic artery, and bile duct
what are lobules
hexagonal shaped units of hepatocytes that surround a central vein. each lobule contain multiple bile duct, portal vein and hepatic artery that form a portal triad. blood flows in from the artery and passes through the sinusoids to allow efficient exchange
what is the hepatic macrophage
stellate, star shaped, removed bacteria and damaged erthryocytes. resides in sinusoids
hepatocyte functions
can produced 900ml of bile/day, stores fat soluble vitamins like A, converts ammonia to urea, protein and glycogen synthesis, secrete GF if liver injured
gall bladder
“potential space” organ, mucosa expands to fill, up to 10x4cm when fully expanded, stores and concentrates bile, mucosa contracts to expel contents
gall bladder micro anatomy
microvilli on the columnar epithelium to increase SA, then lamina propria that contains blood vessels, lymphatics and nerve fibres, then the smooth muscle layer which helps to contract to expel bile, then mucosa
what is the composition of bile
bile salts: to emulsify fats, can be recycled via the enterohepatic circulation
bile pigments – bilirubin: is a product of hemoglobin breakdown, metabolized by gut flora, stercobilin gives feces the brown color
cholesterol: excess secreted in bile
triglyceride, phospholipids and electrolytes
enterohepatic circulation of bile acids
- 0.5g/day produced
- secreted into bile and stored in gall bladder
- when food enters the SI, cholecystokinin (CCK) hormone is released and bile is secreted into intestine
- some bile is passively reabsorbed in the upper intestine
- most bile reabsorbed in the ileum via ASBT (apical-dependent bile salt transporter)
- then to liver via portal vein
- 95% of bile recirculated back to liver and rest is excreted with feces
CCK
cholecystokinin, synthesized by enteroendocrine cells, mostly in duodenum and jejunum
hormones involved in hunger and satiety
CCK, ghrelin, glucagon, insulin, adrenaline, leptin
nerve involved in hunger and satiety
vagal nerves
ghrelin
hormone released by the stomach that stimulates hunger, levels increase before meals and decrease after eating
leptin
hormone produced by fat cells, acts on the brain to suppress appetite and increase energy expenditure, higher levels indicate satiety
gall stones
crystallization due to excess cholesterol or lack of bile salts,
symptoms include: pain during gallbladder contraction, bile duct blockage leading to jaundice
treatment of gallstones
removal, dissolution, sonication
hepatitis and causes
inflammation of liver, caused by viruses HepA -> HepF
HepA and E are transmitted via GI
HepB and C are transmitted via blood contact
can also be caused by drugs, alcohol, and autoimmunity
symptoms of hepatitis
flu-like, jaundice, appetite loss, swelling of liver and spleen, may be asymptomatic
alcoholic liver disease
risk factors: drinking without food, low vit A and E, genetics
how?
- fatty liver (accumulation of fatty acids)
- alcoholic hepatitis
- cirrhosis of liver (end stage of inflammation, collagen, fibrosis, liver failure)
liver can regenerate, but if toxic agent persists, it won’t.
cirrhosis
progressive liver disease characterized by the replacement of healthy liver tissue with scar tissue
typically the end stage of various liver diseases eg chronic hepatitis, alcohol-related liver disease, NAFLD, autoimmune liver diseases
cirrhosis symptoms
- fatigue and weakness
- jaundice
- loss of appetite and weight loss
- abdominal pain and swelling
- easy bruising and bleeding
- spider veins
- mental confusion or changes in personality
cirrhosis treatments
managing the underlying cause, relieving symptoms, and preventing complications, liver transplant
portal hypertension
scar tissue obstructing blood flow through hepatic portal system.
small veins connecting to vena cava may burst due to pressure
caused by thrombosis and liver cirrhosis
symptoms of liver hypertension
blood vomit
esophageal varices (enlarged and swollen veins that develop in the lower part of the esophagus)
caput medusae (dilated and swollen veins that radiate outward from the belly button)
ascites (accumulation of fluid in peritoneal cavity)
