Question

What is the function of Cnidoblast in Phylum Cnidaria?

Answer 1

Hint: A cnidoblast is an explosive cell containing a giant secretory organelle that defines the Phylum Cnidaria. Cnidaria are used for prey capture and as a defense mechanism from predators.

Complete answer:
Cnidae is used to capture its prey and to protect them from predators. Cnidoblast or nematocysts are the inflammatory cells present in the Phylum Cnidaria organisms. Each cnidoblast or nematocysts cell is identified by an organelle called a cnidocyst, or nematocyst, which contains toxic chemicals. Each cnidocyte contains an organelle called cnida, cnidocyst, nematocyst, ptychocyst or spirocyst. This organelle consists of a bulb-shaped capsule which contains a hollow coiled tubule structure that is compacted. The immature cnidocyte is called cnidoblast or nematoblast. The outer side of the cell has a hair-like cnidocil which functions as a mechano- and chemoreceptor. Once the trigger is activated, the tubular shaft of the cnidocyst is released and, in the case of an incoming nematocyst, a forcefully released tube plunges into the target body.

Note:
The cnidocyst capsule which can store a large amount of calcium ions, which are released from the capsule into the cnidocyte cytoplasm when the trigger is activated. This causes a large calcium gradient concentration in the cnidocyte plasma membrane. The resulting osmotic pressure causes fluid to rapidly enter the cell. This increase in the volume of fluid in the cytoplasm forces the coiled cnidae tubule to eject quickly. Prior to the removal of the attached tube of cnidae is located inside the cell in the "internal" state. The resulting pressure caused by the entry of water into the cnidocyte and the opening of the capsule tip or operculum structure, causes a strong ejection of the cnidae tubule which makes it plunge into the prey organism.