Question

Metabolism of crystalline lens.

Hint:

Maintaining proper hydration and metabolic balance in the lens is essential for preventing cataract formation.

Answer 1

Step 1: Metabolism of the Crystalline Lens.
The crystalline lens is avascular, meaning it does not have a blood supply, so it depends on the aqueous humor and vitreous body for nutrition. The lens is composed mainly of water and proteins, and its metabolism is crucial for maintaining transparency and function.

1. Energy Metabolism:
The lens relies on anaerobic glycolysis for energy production. Glucose is metabolized into lactic acid as there is minimal oxygen in the lens. The lens also utilizes some pentose phosphate pathways for antioxidant production, which helps in preventing oxidative damage.

2. Protein Synthesis and Degradation:
The lens proteins, particularly crystallins, are crucial for maintaining the lens's transparency. Protein synthesis in the lens occurs continuously, and any damage to proteins, particularly by UV light or oxidative stress, leads to cataract formation. The balance between protein synthesis and degradation is vital for lens function.

3. Ion Transport:
The lens maintains its internal environment through ion transport mechanisms. Na+/K+ ATPase pumps and other ion channels regulate ionic balance, helping to maintain lens shape and transparency. Disruption of these processes can lead to swelling or opacification of the lens.

Step 2: Conclusion.
The metabolic processes of the crystalline lens are crucial for maintaining its clarity and proper function. Disruptions in these metabolic processes can lead to cataract formation and other lens disorders.