LoB excretion
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- Created on: 24-11-17 11:43
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- LoB: The structure and functions of the mammalian liver
- The liver is involved in carrying out many metabolic processes so it is essential that it has a good supply of blood at all times.
- The hepatic artery: this receives oxygenated blood from the heart via the aorta. This oxygen is essential for aerobic respiration which the liver cells do a lot of as they carry out a lot of MP which require ATP.
- The hepatic portal vein: this receives deoxygenated blood from the digestive system. The liver cleans this blood of toxic compounds absorbed in the intestines and the uncontrolled products of digestion.
- Blood leaves via this vein and rejoins the vena cava.
- The bile duct is also found in the liver. Bille has functions in digestion and excretion. Bile is stored in the gall bladder and then brought to the liver when it is needed for digestion.
- In order to ensure the greatest possible contact between the blood and the liver cells, it is divided into lobes which are then divided into lobules which are cylindrical
- Kupffer cells move about within the sinusoid breaking down and recycling old RBC.
- Blood from the artery and vein mix together and is passed along a special chamber called a sinusoid which is lined with hepatocytes. When blood reaches the end of the sinusoid the concentration of many of its components has been regulated and modified.
- Liver cells
- Contains many many organelles for all the metabolic processes they carry out
- Dense cytoplasm
- Cuboidal with microvilli
- Metabolic functions
- Controll BGL, AA levels, lipid levels
- Synthesis of bilie, proteins, cholesterol
- Storage of viatmins A, D, B12, Fe, glycogen
- Glycogen forms granules in the cytoplasm of hepatocytes and an be broken down to release glucose into the blood when required.
- Detoxification of alcohol and drugs
- The liver contains enzymes e.g catalase, cytochrome P450, that are able to render toxic molecules less toxic.
- Alcohol is broken down by enzyme ethanol dehydrogenase, producing ethanal which is broken down by ethanal dehydrogenase to produce the final product, ethanoate.
- Breakdown of hormones
- Deamination is the process of removing the Amino group from AA to produce ammonia. (and keto acid).
- The products of this process enter the ornithine cycle which produces urea
- The liver is involved in carrying out many metabolic processes so it is essential that it has a good supply of blood at all times.
- In order to ensure the greatest possible contact between the blood and the liver cells, it is divided into lobes which are then divided into lobules which are cylindrical
- Kupffer cells move about within the sinusoid breaking down and recycling old RBC.
- Blood from the artery and vein mix together and is passed along a special chamber called a sinusoid which is lined with hepatocytes. When blood reaches the end of the sinusoid the concentration of many of its components has been regulated and modified.
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