Main cause of tiresome feeling in the sportsman is the secretion of :

Question

Accepted Answer

Explanation:

1. **Correct Answer: Lactic Acid (Option 3)**

Lactic acid is the correct answer because it is a byproduct of anaerobic respiration, which occurs when the body exercises intensely and the oxygen supply to the muscles is insufficient. During such high-intensity activities, the body relies on anaerobic metabolism to produce energy, leading to the accumulation of lactic acid in the muscles. This accumulation is associated with muscle fatigue and the tiresome feeling experienced by athletes. The presence of lactic acid can cause a burning sensation in the muscles, which is a common experience for sportsmen during strenuous activities.

2. **Explanation of Incorrect Options:**

- **Citric Acid (Option 1):** Citric acid is a component of the citric acid cycle (Krebs cycle), which is part of aerobic respiration. It plays a crucial role in energy production in the presence of oxygen. However, it is not directly associated with muscle fatigue or the tiresome feeling in athletes. Citric acid does not accumulate in muscles during exercise and is not responsible for the sensation of fatigue.

- **Pyruvic Acid (Option 2):** Pyruvic acid is an intermediate in both aerobic and anaerobic respiration. In aerobic conditions, pyruvic acid is further metabolized in the citric acid cycle. In anaerobic conditions, it is converted into lactic acid. While pyruvic acid is involved in energy metabolism, it is not the direct cause of muscle fatigue. Instead, it is the conversion of pyruvic acid to lactic acid that leads to the accumulation of lactic acid, which is responsible for the tiresome feeling.

- **Synovial Fluid (Option 4):** Synovial fluid is a viscous fluid found in the cavities of synovial joints. Its primary function is to reduce friction between the articular cartilage of synovial joints during movement. It is not involved in energy metabolism or muscle fatigue. Therefore, synovial fluid is unrelated to the tiresome feeling experienced by sportsmen during intense physical activity.

In conclusion, lactic acid is the correct answer as it directly contributes to the feeling of fatigue in athletes due to its accumulation during anaerobic respiration. The other options do not play a role in causing this sensation.