Unit 8 Week 2: Chlamydia and risky behaviour Flashcards
physiological functions of the liver
bile production
carbohydrate metabolism
lipid metabolism
protein and ammonia metabolism
storage functions
bile production liver
hepatocytes
into the bile canaliculi to smaller ducts then large ducts then eventually to the duodenum or gall bladder
following the secretion of bile into the duodenum undergoes enterohepatic circulation
bile components arent excreted are recylced by conversion into bile acids by gut bacteria for reuse by absorption in ileum
components of carbohydrate metabolism
glycogenolysis
gluconeogenesis
glycolysis
glycogenesis
glycogenolysis
liver can break down glycogen, stored form of glucose, into glucose-6-phosphate. This process is stimulated by the hormone glucagon
gluconeogenesis
liver can synthesis new glucose molecules from non carb resources such as amino acids, lactate, glycerol. This is stimulated by the hormones glucagon and cortisol
glycolysis
liver can also use glucose for energy, glucose is converted into pyruvate, enters citric acid cycle to generate ATP
glycogenesis
can store excess glucose as glycogen. Stimulated by the hormone insulin
componetns of lipid metabolism
lipogenesis
lipolysis
beta oxidation
lipoprotein metabolism
lipogenesis
process of synthesising new fatty acids from glucose, amino acids and other precursors. Synthesises and releases triglycerides, stored in adipose tissue as a long term energy source
lipolysis
breaking down and storing fat into fatty acids. Stimulated by hormones such as glucagon and adrenaline
beta oxidation
beta oxidation of fatty acids into acetyl-CoA, which then enters the citric acid to generate ATP
lipoprotein metabolism
involved in the synthesis and metabolism of lipoproteins which are responsible for transporting lipids through the body, low and high density lipoproteins
components of protein and ammonia metabolism
protein synthesis
amino acid catabolism urea cycle
protein synthesis
synthesis many plasma proteins, including albumin, fibrinogen and globulins, these proteins are responsible for maintaining osmotic pressure and transporting molecules
amino acid catabolism
breaks down amino acids, used for energy or synthesis or other molecules, converted to pyruvate, acetyl CoA or other intermediates that then enter the citric acid
urea cycle
converting toxic ammonia into urea, involves a series of enzymatic reactions that occur in the liver, resulting urea is excreted in the urine
storage functions of the liver
glycogen
vitamins
minerals
drug and toxin
glycogen storage
liver stores glycogen, broken down into glucose when the body needs energy
vitamin storage
storage of several vitamins, including vitamins A, D and b12, released into blood stream when needed
mineral storage
stores minerals such as Iron and copper, these are used for a variety of functions such as oxygen transport and enzyme function
drug and toxin storage
can store certain drugs and toxins, can accumulate in the liver overtime, can lead to liver damage or dysfunctions if it reaches toxic levels
pathophysiology of alcohol related liver disease
alcohol readily absorbed from stomach
mostly absorbed from the small intestine
cant be sotred
mainly catabolised in he liver by alcohol dehydrogenase, ADH and microsomal enzyme oxidation system, MEOS
alcohol metabolism via ADH pathways
ADH, a cytoplasmic enzyme, oxidizes alcohol into acetaldehyde.
Acetaldehyde dehydrogenase (ALDH), a mitochondrial enzyme, then oxidizes acetaldehyde into acetate.
Chronic alcohol consumption enhances acetate formation.
These oxidative reactions generate hydrogen, which converts nicotinamide-adenine dinucleotide (NAD) to its reduced form (NADH), increasing the redox potential (NADH/NAD) in the liver.
The increased redox potential inhibits fatty acid oxidation and gluconeogenesis, promoting fat accumulation in the liver.
alcohol metaoblism via MEOS pathway
Chronic excessive alcohol consumption induces the MEOS (mainly in endoplasmic reticulum), increasing its activity.
The main enzyme involved is CYP2E1.
When induced, the MEOS pathway can account for 20% of alcohol metabolism.
This pathway generates harmful reactive oxygen species, increasing oxidative stress and formation of oxygen-free radicals.