Question

What gets increased in blood if liver becomes functionless? (a) Urea (b) Ammonia (c) Uric acid (d) Proteins

Short answer

The substance that increases in blood if the liver becomes functionless is (b) Ammonia.

Step-by-step solution

Understanding the biological process involving liver

The liver plays a crucial role in breaking down and filtering out waste products from the body. The liver transforms harmful ammonia into urea, which the body can easily excrete. If the liver becomes functionless, it cannot convert ammonia into urea, causing ammonia to accumulate in the blood.

Identifying the correct answer

Since the liver cannot convert ammonia to urea when it is functionless, the concentration of ammonia in the blood would increase. Therefore, the correct answer is (b) Ammonia.

Key concepts

Understanding Ammonia Toxicity

Ammonia is a byproduct of protein metabolism and is normally converted to a less toxic substance, urea, by the liver. This conversion is important because ammonia is highly toxic, especially to the brain. Elevated levels of ammonia in the blood, termed hyperammonemia, can cause neurological impairment and severe damage.

When proteins are broken down in the body, ammonia is one of the waste products formed. The liver's role is to neutralize ammonia by converting it into urea through the urea cycle. If the liver is compromised, this process cannot occur efficiently, resulting in the accumulation of ammonia in the bloodstream.

High levels of ammonia can disrupt normal brain function, leading to symptoms such as confusion, fatigue, or in severe cases, even coma or death; this condition is known as hepatic encephalopathy. Ammonia toxicity is therefore a severe medical concern and is indicative of liver dysfunction.

The Urea Cycle: A Detoxifying Pathway

The urea cycle is a series of biochemical reactions that occur mainly in the liver and, to a lesser extent, in the kidneys. It is the primary way in which mammals convert toxic ammonia into urea, a compound that is easily excreted in the urine.

In the first step of the urea cycle, ammonia reacts with carbon dioxide to form carbamoyl phosphate. Subsequently, a series of enzymatic reactions transform carbamoyl phosphate into urea. This cycle is not only important for the detoxification of ammonia but also for maintaining the nitrogen balance in the body.

Each step of the urea cycle is facilitated by specific enzymes. A deficiency or malfunction in any of these enzymes can lead to an accumulation of ammonia. Thus, understanding the urea cycle's role in waste removal is crucial for comprehending how liver function affects overall health.

Liver Failure and Its Implications

Liver failure occurs when the liver loses the ability to carry out its essential functions, one of which is detoxifying the blood. The signs of liver failure can vary and include jaundice, abdominal pain, and swelling, as well as increased levels of blood toxins such as ammonia.

Liver failure can be acute or chronic. Acute liver failure can occur rapidly, within days or weeks, and is often the result of medication overdose or poisoning. Chronic liver failure, on the other hand, develops more slowly and is usually the result of diseases such as cirrhosis or hepatitis. In both cases, the liver's inability to carry out the urea cycle leads to the accumulation of toxic substances in the body.

When the liver fails, its detoxification processes, including the urea cycle, are compromised. This results in the buildup of toxins such as ammonia in the bloodstream. Such toxicity can significantly impair bodily functions and is life-threatening, underscoring the critical nature of liver health in waste removal.