5.2.2- The structure of the liver Flashcards
What is the name of liver cells?
Hepatocytes
Why is it important that the liver has a good supply of blood?
The liver has an important role in homeostasis
What does the internal structure of the liver allow it to do?
Ensures that as much blood as possible flows past as many liver cells. This enables the liver cells to remove excess or unwanted substances from the blood and return substances to the blood to ensure concentrations are maintained
What is the hepatic artery?
- Oxygenated blood from the heart travels from the aorta via hepatic artery into the liver.
- This supplies the oxygen that is essential for aerobic respiration.
Why is it important that the liver has a good supply of oxygen for aerobic respiration?
The liver cells are very active, because they carry out many metabolic processes.–> Many of these processes require energy in the form of ATP –> Important it has a good supply of oxygen for aerobic respiration
What it the hepatic portal vein?
- Deoxygenated blood from the digestive system enters the liver via the hepatic portal vein.
- This blood is rich in the products of digestion –> The concentration of various substances will be uncontrolled as they have just entered the body from he products of digestion in the intestines
- Blood may contain toxic compounds that have been absorbed from the intestine.
How does blood leave the liver?
Via the hepatic vein.
How does the blood return to the body’s normal circulation?
Hepatic vein rejoins the vena cava
A fourth vessel is connected to the liver, what is it called?
Bile duct
What is the bile duct?
- Bile is a secretion from the liver which has functions in digestion and excretion.
- The bile duct carries bile from the liver to the gall bladder, where it is stored until required to aid the digestion of fats in the small intestine
What does bile contain?
Some excretory products such as bile pigments like bilirubin which will leave the body with the faeces
What shape are the lobules?
Cylindrical
What do the hepatic artery and hepatic portal vein split into?
Smaller and smaller vessels –> These vessels run between and parallel to the lobules, these are known as
inter-lobular vessels.
At intervals, branches from the hepatic artery and the hepatic portal vein enter the lobules, what happens next?
- Blood from the two blood vessels is mixed and passes along a special chamber called sinusoid
What happens when the blood flows through the sinsuoids
Becomes close in contact with the liver cells/. These cells are able to remove substances from the blood and return other substances to the blood
What are Kupffer cells?
- Specialised macrophages that move about within the sinusoids.
What are the primary functions of Kupffer cells?
Breakdown and recycle old red blood cells. One of the products of haemoglobin breakdown is bilirubin which is one of the bile pigments excreted as part of the bile
Where is bile made and where is it released?
Bile is released into the bile canaliculi. The bile canaliculi join together to form the bileduct, which transports the bile to the gall bladder.
What happens when blood reaches the end of the sinusoids?
Concentrations of many of its components have been have been modified and regulated.
What is at the centre of each lobule
A branch of the hepatic vein known as the intralobular vessel.
The sinusoids empty into this vessel.
What joins together to form the hepatic vein?
The branches of the hepatic vein from different lobuels join together to form the hepatic vein, which drains blood from the liver.
Liver cell, hepatocytes. (Key information)
- Relatively unspecialised
- Cuboidal shape with many microvili on their surface
What are the metabolic functions of hepatocytes (liver cells) (4 Points)
- Protein synthesis
- Transformation and storage of carbohydrates
- Synthesis of cholesterol and bile salts
- Detoxification
This means that their cytoplasm is very dense and is specialized in the number of certain organelles that it contains
