Liver Structure & Function Flashcards
Largest organ in body is
Liver (1.4kg/3lb)
Location of liver
upper right quadrant of abdomen (tucked against inferior surface of diaphragm)
Liver has 2 major lobes
Right > Left
2 Minor lobes
Caudate, Quadrate
Left & right lobe separated by
Falciform ligament
Caudate lobe location
sits posteriorly & above quadrate lobe
Top area of liver is
bare
other areas of liver covered by
connective tissue capsule & visceral peritoneum
Septa divide liver into
hexagonal lobules
Portal triad:
hepatic portal vein
hepatic artery
hepatic duct
(located at each corner of hexagonal lobule)
Hepatic cords radiate out from
central veins
Hepatic cords composed of
hepatocytes (functional cells of liver)
Spaces between hepatic cords =
hepatic sinusoids (blood channels)
Spaces between hepatic cords =
hepatic sinusoids (blood channels)
Hepatic portal vein & hepatic artery bring blood into hepatic sinuisoid and drain into
central vein
Bile canaliculus bring bile out of lobule and into
bile duct
Hepatocyte take nutrients from
hepatic portal vein
Hepatocytes functions:
Acts as nutrient storage and interconversion (glucose to amino acids)
Detoxifies blood
Alimentary role of liver:
production & secretion of bile
6 components of bile:
- Bile acids (soluble fats)
- Lecithin (soluble fats)
- Cholesterol (soluble fats)
- Bile pigment (bilirubin, from haemoglobin)
- Toxic metals (are detoxified in liver)
- Bicarbonates (acid neutralising)
What are bile pigments?
Breakdown products of haemoglobin from old/damaged erythrocytes
Predominant bile pigment =
Bilirubin
Bilirubin colour
yellow bile
When Bilirubin modified by bacterial enzymes (what colour?)
brown faeces
Some bilirubin reabsorbed and excreted in urine (what colour?)
yellow urine
Bile acids are made from
cholesterol in liver
Before secretion, bile acids conjugated with
glycine or taurine to form bile salts
Secreted bile salts recycled via
enterohepatic circulation
Most bile acids reabsorbed in
distal ileum
Describe the Gall bladder
Sac structure below liver
Secretes into cystic duct which connects into bile duct
Gall bladder has 3 layers:
- Mucosa (folded, but straightens with bile enters)
- Muscularis (smooth muscle)
- Serosa (connective tissue)
How is bile secretion controlled?
- Sphincter of Oddi
- CCK
Function of Sphincter of Oddi
- Controls release of bile & pancreatic juice into duodenum
- When closed, bile goes into gall bladder
secretion stimulates what release?
HCO3
CCK causes relaxation of
sphincter of oddi & gall bladder contraction