What is the meaning of nematocysts?
: one of the stinging capsular organelles of the tentacle of a cnidarian (such as a box jellyfish or sea anemone) that contains a coiled, hollow, usually barbed, venomous thread which is discharged especially for catching prey and defending against enemies Each nematocyst contains a spiral-coiled thread tipped with a …
Is nematocyst and cnidocyte the 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.
What are Cnidae and nematocysts?
Nematocysts are a type of cnidae, and it is the presence of cnidae that separates jellyfish and other cnidarians from other animals. Cnidae are among the most complex intracellular secretion products known.
What are the different types of nematocysts?
In Hydra, four types of nematocysts are present: the small desmonemes, with a tightly coiled tubule used for prey attachment; the holotrichous and spineless atrichous isorhizas; and the large stenoteles, with a prominent stylet apparatus at the tubule base employed for piercing solid cuticle structures (8–10).
What is another name for nematocyst?
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 does nematocyst look like?
In spite of large variations in size and morphology, nematocysts share a common build comprising a cylindrical capsule to which a long hollow thread is attached. The thread is inverted and coiled within the capsule and may be armed with spines in some nematocyst types.
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.
What is Stenotele?
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.
What is nematocyst Class 9 answer?
Solution. The stinging cells present at tentacles of aquatic animals like jelly fish, hydra, etc in phylum coelenterata is called nematocyst (cnidoblast)
What are three types of nematocysts?
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….Cnida
- Nematocyst. This is the main type, present in all Anthozoa.
- Ptychocyst. This puts out a sticky substance.
- Spirocyst.
What are nematocysts Class 5?
What are nematocysts Class 5? A capsule within specialized cells in the tentacles of cnidarians, such as jellyfish and corals, containing a barbed, threadlike tube that delivers a toxic sting to predators and prey.
What is the alternative name for nematocysts?
…intracellular stinging capsules, known as nematocysts or cnidae, which give the phylum its name. The alternative name, coelenterate, refers…. When stimulated by chemical or mechanical cues, a lidlike structure on the top of the capsule pops aside, and the thread everts explosively with a twisting motion.
How does a nematocyst work like a harpoon?
The cell works a bit like a living harpoon. Before the nematocyst fires, its barb stays coiled inside the cell in a chamber where it is bathed in venom. When the nematocyst comes in contact with something else — such as a fish or your leg — the tiny harpoon fires. The barb sinks into the target, delivering a dose of venom.
Where does the nematocyst get its venom from?
Before the nematocyst fires, its barb stays coiled inside the cell in a chamber where it is bathed in venom. When the nematocyst comes in contact with something else — such as a fish or your leg — the tiny harpoon fires. The barb sinks into the target, delivering a dose of venom. Nematocysts are most associated with jellyfish.
How are nematocysts used to paralyze prey?
On tentacles they form “battery of nematocysts” which are used for paralyzing the prey. A battery consists of one or two large central nematocysts surrounded by 10-12 smaller ones. The discharge of nematocyst thread tube from the cnidocyte takes place due to mechanical or chemical stimuli received by the cnidocil.