S8) The Liver Flashcards
Describe the hepatic portal system
The hepatic portal circulatory system involves blood passing through two sets of smaller vessels before returning to the heart
Identify 6 types of substances which travel to the portal vein
- Water
- Water soluble vitamins
- Electrolytes
- Carbohydrates e.g. glucose, galactose, fructose
- Proteins e.g. amino acids, dipeptides, tripeptides
- Toxins e.g. ammonia, chemicals, pathogens
Identify 2 types of substance which do not travel through the portal vein
- Lipids
- Fat soluble vitamins (ADEK)
What are dietary lipids?
Dietary lipids are mostly triglycerides, cholesterol and phospholipids
How are lipids absorbed?
- Lipids are digested by lipases
- Lipids are taken into the cells and processed into chylomicrons
- Chylomicrons are taken up by lacteals
Identify the 5 major functions of the liver
- Storage
- Anabolism
- Catabolism
- Exocrine secretion
- Endocrine secretion
Identify 3 substances which are stored by the liver
- Iron
- Glycogen
- Vitamins
Identify 3 substances which are produced by the liver
- Albumin
- Glycogen
- Coagulation factors
Identify 3 substances which are broken down by the liver
- Drugs
- Hormones
- Haemoglobin
Identify an exocrine secretion of the liver
Bile via bile duct
Identify 3 substances which are secreted by the liver into the blood
- Angiotensinogen
- Thrombopoietin
- IGF-1
Hepatocytes constitute 80% of the liver cell population and can regenerate.
Describe 6 other unique features of hepatocytes
- Numerous mitochondria
- Numerous peroxisomes (full of oxidising agents)
- Numerous free ribosomes
- Numerous rough and smooth ER
- Numerous Golgi complexes
- Glycogen deposits
What are Kupffer cells and what do they do?
- Kupffer cells are monocyte derived specialist macrophages that form part of the lining of the sinusoids.
- They patrol the sinusoids, recycling old red blood cells and ingesting pathogens
What is a sinusoid and what is unique about its structure?
- A sinusoid is an irregular tubular space for the passage of blood in the liver, spleen and bone marrow
- Its endothelium is perforated with large holes, allowing Kupffer cells to migrate into liver tissue at sites of inflammation and damage
What are stellate cells?
Stellate cells are liver cells which are full of cytoplasmic vacuoles containing Vitamin A