Liver structure and function Flashcards
where is the liver located in the body
upper right quadrant of abdomen (tucked against inferior surface of diaphragm)
name the major and minor lobes
major - left and right
minor - caudate and quadrate
what is the porta
the single entry exit point for all vessels, ducts and nerves to the liver - found on the inferior surface
liver blood supply
hepatic portal vein, hepatic artery
liver lymphatic vessels and ducts
hepatic lymphs, left/right hepatic ducts join to form the common hepatic duct
liver nerve supply
hepatic nerve plexus
talk through the route from the common hepatic duct to the duodenum
- comon hepatic duct joined by cystic duct from gallbladder
- join to form the common bile duct
- common bile duct joins with the pancreatic duct
- travel to the major duodenal papilla (sphincter of Oddi)
- enter into duodenum
what is the liver covered by
a connective tissue capsule and visceral peritoneum except for the bare area
what is the bare area of the liver
small area on the diaphragmatic surface surrounded by the coronary ligament - not covered in the capsule
what is the septa
a branching network of connective tissue that goes into the body of the liver for support - divided the liver into hexagonal lobules
what comprises the portal triad
hepatic portal vein, hepatic artery, hepatic duct
where is the portal triad located
at each corner of a hexagonal lobule
what is found at the centre of each lobule
hepatic veins that go to the IVC
what are hepatic cords
composed of hepatocytes (functional liver cells) they radiate out from central veins (like wheel spoke)
what lie between the hepatic cords
hepatic sinusoids - blood channels
what is the bile canaliculus and where does it lie
it is a cleft like lumen that lies between cells within each hepatic cord
what are the role of hepatocytes
- bile synthesis
- nutrient storage (glycogen, fat, vits (B12, A, D, E, K) Cu, Fe)
- nutrient interconversion
- detoxification
what is the path venous blood takes through the liver
- O2 depleted/nutrient rich blood in through Hepatic portal vein
- through hepatic sinusoids
- to central veins
- to hepatic veins
what is the path arterial blood takes through the liver
- O2 rich/nutrient depleted blood in through Hepatic artery
- through hepatic sinusoids
- to central veins
- to hepatic veins
what is the path taken by bile through the liver
- continuously going between hepatic sinusoids and hepatocytes
- from hepatocytes travel to cannaliculi
- travel to hepatic ducts
What is the alimentary role of the liver
production and secretion of bile
what are the six components of bile and where are they secreted from
- bile acid
- lecithin
- cholesterol
- bile pigments
- toxic metals
- bicarbonate
1-5 secreted by hepatocytes
6 secreted by duct cells
what is the role of bile acids, lecithin and cholesterol
synthesised in the liver to solibulise fat
what is the role of bicarbonate
neutralisation of acid chyme
what are bile pigments made from
bilirubin - breakdown product of haemoglobin form old/damaged erythrocytes
How does bilirubin cause yellow bile
extracted from blood by hepatocytes and secreted into bile
How does bilirubin cause brown faeces
modified by bacterial enzymes = brown pigments
How does bilirubin cause yellow urine
reabsorbed and excreted in urine
what are bile acids synthesised from
synthesised from cholesterol in the liver
what happens to bile acids before secretion
conjugated with glycine or taurine to increase solubility - create bile salts
secreted bile salts are recycled via what circulation
enterohepatic
list the enterohepatic circulatory route
- liver
- bile duct
- duodenum
- ileum
- hepatic portal vein
- liver etc
where is the gallbladder found
it is a sac like structure on the inferior surface of the liver
what are the three wall layers
- mucosa (folded - rugae - for expansion
- muscularis (smooth muscle - for contraction)
- Serosa - connective tissue
what does the gallbladder go into
the cystic duct - common bile duct
what controls bile secretion
the sphincter of Oddi controls release of bile and pancreatic juice into duodenum - When contracted (closed) bile forced back into gallbladder
how does the gallbladder concentrate bile
through the absorption of Na+ and H20 - bile is concentrated 5-20 times
what controls the sphincter of Oddi
fat in the duodenum releases CCK
- causes sphincter of Oddi to relax
- casues gallbladde to contract
summarise how secretin cases neutralisation
1.Acid in duodenum
2. causes release of Secretin
3. Gastric acid secretion decreases
4. Gastric emptying decreases
5. Duodenal HCO3 secretion increases
6. Pancreatic HCO3 secretion increases
7. Bile duct HCO3 secretion increases
summarise how cholecysrokinin (CCK) causes digestion
- Fat/amino acids in duodenum
- causes release of CCK
- Gastric emptying decreases
- Pancreatic enzyme secretion increases
- Gallbladder contraction occurs
- Relaxation of Sphincter of Oddi
