Organ-specific immunity: LIVER - Physiology & Innate Immunity Flashcards
Anatomy: of what parts does the liver consist?
Major left and right lobes + smaller inferior lobes
What is special about the liver as opposed to any other organ?
Dual blood supply
What is meant with this dual blood supply?
- Nutrient-rich, oxygen-poor blood via portal vein from intestines
- Oxygen-rich blood via hepatic artery
What are the three immunity characteristics of the liver?
- Protection against pathogens and food toxin from the intestine
- Removal of translocated intestinal bacteria and bacterial toxins
- Tolerance to food antigens and commensal bacteria
Why does the liver need a tightly controlled immunity?
Tolerate antigens, but generate immune response against potential threats
Anatomy: What can be said about the structuring of hepatocytes?
Sheets of hepatocytes, centered around a central vain.
How are hepatocytes grouped?
In portal triads
What does this grouping of hepatocytes in portal triads mean for the blood flow? (direction)
Blood flowing from the portal vain towards the central vain
Anatomy: What is collected in the bile duct?
Drainage of hepatocytes
What is important about the blood flow from the portal vain to the central vain? What does that allow for?
Flow of blood is quite slow. Allows for hepatocytes to really come in contact with whatever is in that blood.
Anatomy: What is between the hepatocytes and the blood? What do they form?
Liver sinusoids and T cells that form an impermeable barrier
What is the Space of Disse (perisinusoidal space) and what is its function?
- Space between sinusoids and hepatocytes
- Microvilli of hepatocytes extend into this space, allowing proteins and other plasma components from the sinusoids to be absorbed by the hepatocytes.
Which cells/substances stay in the vessel and which cells/substances can be directly taken up by hepatocytes?
- Vessel: most cells
- Direct uptake: nutrients
Main functions of the liver (3)
- Metabolism
- Detoxification
- Synthesis
For what kind of immunity is the liver important?
Systemic immunity
Name three examples of the metabolizing function of the liver
- Nutrients
- Amino acid metabolism
- Collestral
What is an example of nutrient metabolism in the liver?
Storing of glucose in the form of glycogen
What is an example of amino acid metabolism in the liver?
Deamination to form urea, which is secreted by the kidneys
What is an example of collestral?
Synthesis of phospholipids
Why is the synthesis of biomolecules important?
Proper functioning immune system
What is an important immune function of the liver?
Synthesis of molecules that are involved in co-agulation and complement system (systemic immunity)
What is the difference between PRRs in the liver and on cell membranes?
The liver PRRs are soluble
What can be said about the secretion levels of PRRs and immunological proteins?
They are not always secreted at equally high levels, especially when a threat is being sensed
Which cytokines lead to an increase of immunologically relevant systemic proteins by the liver? In what kind of situations is this induced?
- IL-6, IL-1, TNF-a
- Inflammation
How are systemic proteins produced by the liver called?
Acute-phase proteins