Answer:
Nematocysts
Step-by-step explanation:
Nematocysts are specialized stinging cells found in cnidarians, a group of animals that includes jellyfish, sea anemones, and corals. These unique cells are used by cnidarians for various purposes, including capturing prey and self-defense.
Nematocysts are capsule-like structures containing a coiled, hollow thread with a barbed or adhesive tip. When triggered by touch or chemical signals, nematocysts rapidly discharge the thread, injecting venom into the target organism. The venom immobilizes or kills the prey, making it easier for the cnidarian to consume.
Here's how nematocysts assist cnidarians in obtaining their food:
1. Capturing Prey: When a potential prey organism comes into contact with the cnidarian's tentacles or body surface, specialized sensory cells on the cnidocyte (the cell containing the nematocyst) detect the presence of the prey. The cnidocyte then fires the nematocyst, launching the harpoon-like thread into the prey's body.
2. Venom Injection: As the nematocyst penetrates the prey's body, it releases venom from specialized venom cells. The venom contains toxins that paralyze or kill the prey, enabling the cnidarian to subdue it effectively. The exact composition of the venom varies among different cnidarian species and can target specific physiological processes of the prey.
3. Prey Handling and Digestion: Once the prey is immobilized, the cnidarian uses its tentacles or other specialized structures to manipulate and guide the captured prey toward its mouth or gastrovascular cavity. The gastrovascular cavity is a central digestive compartment within the cnidarian's body.
4. Extracellular Digestion: Within the gastrovascular cavity, enzymes are secreted to break down the prey's tissues externally. This process is known as extracellular digestion. The dissolved nutrients are then absorbed by the cells lining the gastrovascular cavity and distributed throughout the cnidarian's body for energy and growth.
It's important to note that while nematocysts are primarily used for prey capture and feeding, they also serve as a means of defense for cnidarians. When threatened or touched, cnidarians can discharge their nematocysts to deter or immobilize potential predators or competitors.
In summary, nematocysts are specialized stinging cells found in cnidarians. They aid these organisms in obtaining their food by capturing prey through the injection of venom. Nematocysts play a crucial role in the feeding strategy of cnidarians, allowing them to immobilize and digest their prey efficiently.