Liver And Hepatic Function Flashcards
What does an endocrine gland do
Secretes something directly into the blood stream not via a duct
What does an exocrine gland do
Secretes something onto an epithelial surface via a duct
What are some key functions of the liver
Makes glycogen from glucose and stores it
Synthesis of lipids
Synthesis of proteins
Amino acid synthesis
Protein degradation
Breakdown of drugs, alcohol, hormones
Production and secretion of bile
What is lipolysis
Breakdown of lipids into fatty acids also makes lipoproteins, phospholipids, cholesterol and other lipids
Low levels of what can indicate liver dysfunction
Albumin which is an abundant protein found in the blood
Which vitamins does the liver store
Fat soluble vitamins
Vitamin A, D, E and K
Vitamins A and B12 for up to 4 years and D for months
What minerals can the liver store
Iron and copper
What does the liver do with ammonia
Gets it from the intestines via portal circulation
Turns it into urea through the urea cycle (series of reactions)
The urea is put back into the circulation then excreted by the kidneys
What does the liver do with ethanol
The enzyme alcohol dehydrogenase turns ethanol into acetaldehyde which the build up of makes you feel ill when drinking too much
What does the liver do with drugs
They are metabolised by cytochrome P450 enzymes
Some drugs can induce P450s and increase their levels which make other drugs get broken down too fast
What is the cephalic phase
Preparation for digestion, vagus nerve stimulates secretions
What is the gastric phase
Pancreatic secretions are stimulated by the distension of the stomach
What is the intestinal phase
Hormones are released in response to H+ and amino acids, fatty acids which stimulate pancreatic secretions
What do acinar cells in the pancreas release
Zymogen granules containing digestive enzymes by exocytosis
What do acinar cells do
Move out NA+ causing water to follow into the duodenum
They are intercalated duct cells in the pancreas also regulate ion movement via the cystic fibrosis transmembrane conductance regulator Cl- channel and other ion channels
Bicarbonate is secreted which neutralises the acid as food comes into the duodenum from the stomach
What organ produces hepatic bile
Liver produces and secretes it
What is the common hepatic duct
Hepatocytes secrete bile into canaliculi which feed into larger ducts until they form the duct
What controls the path of bile
The sphincter of oddi
What are the 2 pathways where bile can go
Into the duodenum via common bile duct when SO is relaxed
Into the gallbladder via cystic duct when SO is contracted
Where is bile stored
In the gallbladder in a concentrated form
How is the stored bile released
CCK causes the gallbladder to contract and expel bile and also causes the sphincter of oddi to relax
What does bile do
Key for lipid digestion they emulsify fats during digestion increasing the surface area of lipids and allows enzymes to work efficiently
What gives bile its colour
Bilirubin made from broken down haemoglobin
What helps solubilise the bile salts
Phospholipids
What does the spleen do
Removes old red blood cells and keeps a spare storage of blood in case of haemorrhage
Also makes antibodies and removes antibody coated bacteria and cells through the lymph and blood
What is liver disease most commonly caused by
Obesity
Alcohol misuse
Hepatitis
What do abnormal liver functions cause
Trouble metabolising drugs also goes for kidney disease
Impaired other functions such as protein synthesis
