POLAR CAPSULE Meaning and
Definition
-
A polar capsule, also known as a nematocyst, is a specialized structure found in certain invertebrate animals, particularly in the phylum Cnidaria, which includes jellyfish, sea anemones, and corals. It is a small, sac-like cell that functions as a unique type of stinging or defense mechanism.
The polar capsule is typically contained within the cells of the organism's tentacles or body. When stimulated, such as by physical contact with prey or a threat, the polar capsule explosively releases a coiled thread-like structure known as a cnidocil. The cnidocil rapidly discharges within milliseconds, propelling a barbed filament called a nematocyst towards the target.
Upon contact with the prey or potential predator, the nematocyst injects toxins, paralyzing the prey or serving as a potent deterrent. This allows the organism to capture and immobilize its prey or defend itself against potential threats.
Polar capsules are highly specialized structures that can be found in varying shapes and sizes, adapted to suit the specific needs of different species. They are produced within specialized cells called cnidocytes, which are found in large numbers in the tentacles or oral arms of cnidarians.
Overall, the polar capsule is a remarkable adaptation that enables cnidarians to efficiently capture prey, protect themselves, and establish dominance in their aquatic environments. Its mechanism of explosive discharge makes it an important aspect of the predatory and defense strategies of various cnidarian species.
Etymology of POLAR CAPSULE
The word "polar" has its roots in the Latin word "polus", meaning "axis" or "pole". It is derived from the Ancient Greek word "polos", which also means "axis" or "pivot". "Polar" refers to something related to or located near either of the poles (North or South) on a planet or a celestial body.
The word "capsule" comes from the Latin word "capsula", meaning "small box" or "case". It is derived from the Latin word "capsum", which means "box" or "receptacle". "Capsule" refers to a small, compact, and usually cylindrical or spherical container.
So, when put together, the term "polar capsule" refers to a small, container-like structure that is found in certain organisms, such as parasites like cnidarians.
