What causes a nematocyst to discharge?

A nematocyst consists of a capsule containing a coiled tubule. On triggering, the cyst extrudes this tubule in an extremely rapid manner. This causes an increase in the pressure of the matrix against the cyst wall. We suggest that this nonosmotic pressure increase causes the first and extremely rapid step of discharge.

What is the difference between cnidocyte and nematocyst?

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.

What is the function of the cnidocyte?

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 happens after a nematocyst is discharged?

Types of cnidae They can be divided into the following groups: 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 venomous fluid, hypnotoxin, that either paralyzes the victim or kills it.

What are the stages of a Nematocyst discharge?

It shows the nematocyst in three stages of discharge. First, the inverted harpoon is packed within the capsule. The harpoon is inside-out at this point. Second, a stimulus has led the capsule to pressurize, swinging open the operculum (the trap door at the top), and begin everting the poison filled thread.

What are 4 functions of nematocysts?

Nematocysts are used by organisms for prey capture and feeding, but also for defense, transport, digestion and other various functions [3,4].

What is the relationship between nematocyst and a cnidocyte?

Cnidocyte and nematocyst are two structures that aid in the capturing of the prey by cnidarians. Cnidocyte is an epidermal cell that contains the nematocyst. Cnidoctes can be found in the tentacles of the cnidarians. The nematocyst is the organelle inside the cnidocyte used to inject toxins into the prey.

What are cnidocytes and nematocysts and what is the role of these structures?

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. Nematocysts contain coiled threads that may bear barbs.

What is a cnidocyte used for and how does it work?

Cnidocytes are a distinctive feature of cnidarians (jellyfishes, sea anemones, corals, hydrae, etc.). These are explosive cells used by cnidarians in order to capture their prey (e.g. fish and crustaceans). These cells shoot off threadlike, often toxic, tubule inside the cnidocyst.

What do you mean by Cnidoblast?

Medical Definition of cnidoblast : a cell of a coelenterate that develops a nematocyst or develops into a nematocyst.

What is Nematocyst discharge?

The rapid discharge of stinging cells (nematocytes) in jellyfish, hydra, and other cnidarians is one of the fastest movements in the animal kingdom. After the triggering of exocytosis, a miniature cellular weapon, the nematocyst, is released and stylets punch a hole into the prey’s integument.

What is Stenotele zoology?

stenotele (noun; Greek stenos, narrow; telos, the end): (Cnidaria) A stinging nematocyst; a sprially coiled thread armed with spiral rows of projections that is provided at its distal end with a lid (operculum); a penetrant.

Why do nematocysts discharge from the cnidocyte?

The discharge of nematocyst thread tube from the cnidocyte takes place due to mechanical or chemical stimuli received by the cnidocil. In a resting stage the capsule wall is not permeable to water and there is very high osmotic pressure since the hypnotoxin inside is hypertonic to external water.

What’s the difference between a Cnidaria and a nematocyst?

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.

What kind of cell is a nematocyte?

Nematocyst Definition: A nematocyte (also termed as a cnidoblast or cnidocyte) is an explosive cell which contains a cnidocyst (also recognized as a cnida (plural cnidae) or nematocyst), a giant secretory organelle which could sting other species.

What makes A cnidocyte an explosive cell?

A cnidocyte is an explosive cell having within it a giant secretory organelle (organ) called cnida which is a characteristic of the phylum Cnidaria.