肝功能和红细胞再生

In humans, red blood cells possess minimal organelles and no nucleus in order to carry more haemoglobin

Consequently, red blood cells have a short lifespan (~120 days) and must be constantly replaced

The liver is responsible for the break down of red blood cells and recycling of its components

These components are used to make either new red blood cells or other important compounds (e.g. bile)


Understanding:

• The breakdown of erythrocytes starts with phagocytosis of red blood cells by Kupffer cells

• Iron is carried to the bone marrow to produce haemoglobin in new red blood cells


Kupffer cells are specialised phagocytes within the liver which engulf red blood cells and break them down

Kupffer cells break down haemoglobin into globin and iron-containing heme groups
Globin is digested by peptidases to produce amino acids (which are either recycled or metabolised by the liver)
Heme groups are broken down into iron and bilirubin (bile pigment)

The released iron must be complexed within a protein in order to avoid oxidation to a ferric state

Iron can be stored by the liver within a protein shell of ferritin
Iron can be transported to the bone marrow (where new haemoglobin is produced) within the protein transferrin


The liver is a lobed organ located below the diaphragm that functions to regulate the chemical composition of blood

It receives oxygenated blood via the hepatic artery, which is used to sustain liver cells (hepatocytes)
It also receives nutrient rich blood from the gut via the portal vein
Deoxygenated blood is transported from the liver via the hepatic vein

The liver functions to process the nutrients absorbed from the gut and hence regulates the body’s metabolic processes

It is responsible for the storage and controlled release of key nutrients (e.g. glycogen, cholesterol, triglycerides)
It is responsible for the detoxification of potentially harmful ingested substances (e.g. amino acids, medications, alcohol)
It produces plasma proteins that function to maintain sustainable osmotic conditions within the bloodstream
It is responsible for the breakdown of red blood cells and the production of bile salts

Liver Blood Flow | BioNinja
https://ib.bioninja.com.au/options/option-d-human-physiology/d3-functions-of-the-liver/liver-blood-flow.html

Erythrocyte Recycling | BioNinja
https://ib.bioninja.com.au/options/option-d-human-physiology/d3-functions-of-the-liver/erythrocyte-recycling.html