MRCP UK EXAMINATIONS

ABDOMINAL

CHRONIC LIVER DISEASE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
How is ammonia detoxified by the liver?
A
using ethanol dehydrogenase
B
converted into hydrophobic substances
C
converted into hydrophilic substances
D
converted into urea
Explanation: 

Detailed explanation-1: -The amino acid is transaminated to produce a molecule of glutamate. Glutamate is the one amino acid that undergoes oxidative deamination to liberate free ammonia for the synthesis of urea. Once free ammonia is formed in peripheral tissues, it must be transferred to the liver for the conversation to urea.

Detailed explanation-2: -Ammonia is a toxic product of nitrogen metabolism which should be removed from our body. The urea cycle or ornithine cycle converts excess ammonia into urea in the mitochondria of liver cells. The urea forms, then enters the blood stream, is filtered by the kidneys and is ultimately excreted in the urine.

Detailed explanation-3: -This very important metabolic process is called deamination. In the hepatocytes, NH2 (the amino group) quickly changes into ammonia NH3, which is highly toxic to the body. The liver acts fast to convert ammonia into urea that then can be excreted in the urine and eliminated from the body.

There is 1 question to complete.