What is cnidocytes and its function?

Cnidocytes (‘stinging cells’) are specialized cells that define the phylum Cnidaria (sea anemones, jellyfish, corals and hydras). They contain an “explosive” organelle called cnidocyst that acts as a 600 million-years-old microscopic injection system and is important for prey capture and anti-predator defense.

What are the three types of Cnidae?

There are three main types of cnidae: nematocysts, ptychocysts, and spirocysts, with many variations. Depending on the species, one or more types may be on the organism. Nematocyst. This is the main type, present in all Anthozoa.

Is Cnidoblast and cnidocytes same?

A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive cell containing one giant secretory organelle called a cnidocyst (also known as a cnida (plural cnidae) or nematocyst) that can deliver a sting to other organisms.

What is the function of cnidocytes in cnidarians?

Cnidarians contain specialized cells known as cnidocytes (“stinging cells”) containing organelles called nematocysts (stingers). These cells are present around the mouth and tentacles, and serve to immobilize prey with toxins contained within the cells.

What is the difference between Cnida and nematocyst?

The main difference between cnidocyte and nematocyst is that cnidocyte is a type of cell that helps predation of cnidarians whereas nematocyst is an organelle consisting of a coiled, thread-like stinger.

What is Colloblast cell?

Colloblasts are unique, multicellular structures found in ctenophores. They are widespread in the tentacles of these animals and are used to capture prey. However, unlike cnidocytes, which are venomous cells, colloblasts contain adhesives which stick to, rather than sting the prey.

Are nematocysts and cnidocytes same?

A cnidocyte is an explosive cell having within it a giant secretory organelle (organ) called cnida which is a characteristic of the phylum Cnidaria. A Nematocyst is a specialized sub-cellular organelle (part of the cell) present in cnidocyte. Thus, a nematocyst is essentially a part of a cnidocyte.

Where are cnidocytes located?

Whereas the defining cell type for the sponges is the choanocyte, the defining cell type for the cnidarians is the cnidocyte, or stinging cell. These cells are located around the mouth and on the tentacles, and serve to capture prey or repel predators.

Which is the most complex nematocyst in the world?

Penetrant: The penetrant or stenotele is the largest and most complex nematocyst. When discharged, it pierces the skin or chitinous exoskeleton of the prey and injects the poisonous fluid, hypnotoxin, that either paralyzes the victim or kills it. Glutinant: a sticky surface used to stick to prey,…

What is the discharge mechanism of a nematocyst?

Discharge mechanism. Discharge mechanism of a nematocyst. The cnidocyst capsule stores a large concentration of calcium ions, which are released from the capsule into the cytoplasm of the cnidocyte when the trigger is activated. This causes a large concentration gradient of calcium across the cnidocyte plasma membrane.

What is the function of a cnidoblast in a jellyfish?

A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive cell containing one giant secretory organelle or cnida (plural cnidae) that defines the phylum Cnidaria ( corals, sea anemones, hydrae, jellyfish, etc.). Cnidae are used for prey capture and defense from predators.

How does a nematocyst form from a Golgi vacuole?

The nematocyst forms through a multi-step assembly process from a giant post-Golgi vacuole. Vesicles from the Golgi apparatus first fuse onto a primary vesicle: the capsule primordium. Subsequent vesicle fusion enables the formation of a tubule outside of the capsule, which then invaginates into the capsule.