Week 1- Flashcards
what is the anatomy of the liver? size, segments
-can have hepatic diseases
-it is the largest organ in the body
-has a left and right lobe which are divided into 8 segments called lobules
-capillaries will join to form veins
-bile ducts join to form common bile duct which drains
bile into duodenum after storage and concentration in
the gallbladder
how is each lobule described as containing?
-they each have a central vein, radiating sinusoids (type of blood capillary), bile ducts, hepatocytes and other cells
what is the blood supply like for the liver?
- it has an aorta that carries blood from the heart and branches to the hepatic arteries in the left and right lobe
- has the hepatic vein that carries deoxygenated blood from liver to heart through the inferior vena cava
- hepatic portal vein which carries nutrient rich blood coming from the gastrointestinal tract
- bile ducts that gather and form the common bile duct which then has the gall bladder off it which stores the bile
what is the vascular structure of the liver?
-25% of resting cardiac output
-Hepatic artery –
25% of blood to
liver – oxygen rich
-Hepatic portal vein
– 75% of blood to
liver – nutrient rich coming from the gut
-Leaves by hepatic
vein to vena cava
what is the hepatic lobules described as looking like?
- hexagonal structures and in the middle there is a central vein
- outside there is a portal triad, a branch of the hepatic artery, portal vein and bile duct
how does blood get into the liver?
from the outside through the hepatic artery and portal vein which turn into sinusoidal capillaries then eventually they will join to get the central vein taking deoxygenated blood away
what is the main component of the liver?
hepatocytes its the cells and make and store everything in the liver
what are bile canaliculi? where are they found?
found between hepatocytes they are small branches of the bile ducts that will then take the bile made from the hepatocytes away
what is the portal triad?
portal vein, bile duct and hepatic artery
what is the structure of the hepatic lobule?
- in the centre there is the central vein
- on the outside of the hexagon theres the bile duct, the portal vein and hepatic artery
- between this both there are hepatocytes and bile canaliculus that gathers the bile made by the hepatocytes
what are the important cells that are present in the hepatic lobule?
-hepatocytes
-macrophages
resident macrophages (Kupffer cells) involved with phagocytosis of foreign stuff, can also become inflammatory cells
-fibrocytes- support hepatocytes and are responsible for fibrosis during liver disease.
-hepatic stellate cells, support hepatocytes and are responsible for fibrosis during liver disease.
what are the funcions of the liver?
Metabolism Immunity Storage Detoxification of drugs Synthesis Catabolism Activation Transport Excretion
how is the liver involved with metabolism?
-liver involved with breaking down and storing nutrients
-Carbohydrate
Stores glucose as glycogen
Glycogenolysis in fasting
Gluconeogenesis in fasting
-Lipid
Synthesis of cholesterol cholesterol is carried around in the body by Lipoproteins – VLDL, LDL,
HDL
- Protein
Amino acid synthesis
Breakdown of amino acids to ammonia and then
urea for excretion
in the liver harmful ammonia is converted into what ?
urea
what does the liver detoxify? how does it occur?
- drugs and xenobiotics (contaminants etc)
- Phase I reactions by cytochrome P450 enzymes
- Phase II reactions – conjugation with other compounds to become more hydrophyllic eg gluconosyltransferases