lecture 10 - liver physiology Flashcards
what are the 2 vessels that supply the liver?
hepatic artery and the hepatic portal vein
what does the liver have?
high blood flow and low vascular resistance
what does the hepatic portal vein do?
travels back to the heart – to the rest of the body, carries the nutrients into the liver
first site of processing for most absorbed nutrients
limits entry of toxic substances into systemic circulation by converting them into water-soluble products that can be excreted via urine / bile
what is the liver lobule?
O2 and nutrients come in for the liver to analyse
Anything on a muscle membrane is an epithelial cell
Protects liver from any further damage
hexagonal shape – fit well together, triad of vessels which contain bile duct, portal vein and hepatic artery
what are hepatocytes?
liver cells which make up the majority of the liver volume (80%)
what is the livers responsibility?
metabolism and energy production
what is glycogenesis?
building glycogen out of glucose – store it as glycogen and glycogenolysis – the breakdown of glycogen into glucose to store it
what is lipogenesis?
process by which fatty acids are synthesised from aceytol CoA molecules/ lipolysis – triacylglycerols are broken down to form fatty acids and glycerol – makes useful things which can then be used later
what is glucogenesis?
much more complex phenomenon – can make glucose out of most molecules in the body
what is transamination?
amino groups are removed from amino acids and transferred to acceptor keto –acids
what is deanimation?
removed amino groups from a molecule so the amino group is changed into ammonia
what are triacylglycerols (TAG)?
consists of 3 individual fatty acids (FA) esterified to a glycerol molecule
purpose - form in which lipid energy is stored in the body
what is a protein?
chains of amino acids through peptide bonds - acquired through diets
what are hormones?
Hormones control everything that go on in the body
Insulin and glucagon act as a seesaw
Insulin is released when too much glucose
Glucagon when too little glucose
what is glucagon?
Purpose is to elevate blood glucose by glycogenolysis
- involved in the storage of glucose in the body
what is cortisol?
Released from the adrenal glands
It stimulates liver gluconeogenesis
Increases availability of blood glucose to the brain
what is adrenaline
(epinephrine)?
Released from the adrenal glands
It stimulates liver glycogenolysis, lipolysis
what is carbohydrate metabolism?
Glucose is constantly turned over: molecules being removed and replaced by new glucose molecules
The brain requires stable glucose levels for fuel.
what is glycogenesis?
Synthesis of glycogen from glucose store energy
what is GLUCONEOGENESIS?
Synthesis of glucose from other precursors (amino acids, lactate, glycerol) to maintain supply brain, CNS, RBC
what is GLYCOGENOLYSIS?
Liberate glucose from glycogen into plasma
what happens when we exercise?
needs more o2 – needs to be used in some format – atp turnover, o2 uptake – increases due to increased muscle contraction – other organs need stuff to – controlled and monitored by the liver – if not replenished, will look for others
how does the liver recover from acute exercise?
Body needs to return to homeostasis – needs to replenish glycogen stores – takes on board nutrients – increase amount of glucose in the body
what is cholesterol synthesis?
Body adapts as we take on many cholesterol from our diet
If diets of high unsaturated fats we have lower cholesterol
what is bile salt synthesis?
Bile breaks down fat into smaller molecules
Stored and released when needed
Starts performing as is needed
