Their respiratory system functions as follows:
1. Water Intake: Sharks open their mouths while swimming, allowing water to rush into their oral cavity.
2. Gill Filtration: The water then passes through the shark's gill slits and over specialized structures called gill filaments.
3. Gas Exchange: Within the gill filaments, tiny blood vessels called lamellae are present. Oxygen from the water diffuses across the lamellae into the bloodstream, while carbon dioxide moves from the blood into the water.
4. Water Exit: The oxygenated water exits the shark's body through the gill slits.
Sharks constantly move forward to ensure a continuous flow of water over their gills for efficient gas exchange. Some shark species can also pump water through their gills by using muscles in their pharynx. Additionally, sharks have spiracles, small openings near their eyes, used for additional respiration in certain shark species.
Sharks possess specialized adaptations in their gill systems that aid in respiration and buoyancy regulation. These adaptations vary among different shark species and contribute to their unique survival strategies in aquatic environments.