What is the meaning of cnidocytes?

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 ( pl. cnidae) or nematocyst) that can deliver a sting to other organisms.

What type of cells are cnidocytes?

Cnidocytes, also known as stinging cells, are specialized neural cells that typify the phylum Cnidaria (sea anemones, corals, hydroids, and jellyfish) [1,2,3]. These cells contain an organelle called cnida or cnidocyst, which is the product of extensive Golgi secretions.

What does Cnidaria mean in biology?

noun. any invertebrate animal, as a hydra, jellyfish, sea anemone, or coral, considered as belonging to the phylum Cnidaria, characterized by the specialized stinging structures in the tentacles surrounding the mouth; a coelenterate.

What is the function of cnidocytes in hydra?

Hydra tentacles contain barbed, poison-containing cnidocytes that they use to stun animals, such as water fleas and plankton, before eating them alive. They also use their cnidocytes for self-defense and locomotion.

How do cnidocytes work?

Located on their tentacles, jellyfish’s stinging cells are called cnidocytes. They are small compartments that house a mini needle-like stinger. When an outside force triggers a stinger, the cell opens, letting ocean water rush in.

Is Jelly a medusa or polyp?

Jellyfish have a stalked (polyp) phase, when they are attached to coastal reefs, and a jellyfish (medusa) phase, when they float among the plankton. The medusa is the reproductive stage; their eggs are fertilised internally and develop into free-swimming planula larvae.

Where are cnidocytes located?

Cnidocytes are specialized cells located in the epidermis of all cnidarians. These cells are unique to cnidarians, no other organism possesses them. Cnidocytes are most concentrated within the epidermis of the tentacles.

How does the cnidocytes discharge?

Cnidocyte discharge is, in essence, an explosive event that results in the inverted tubule being extruded through the operculum at the apical end of the cyst with, in the case of penetrant cnidocytes, sufficient force to penetrate the cuticle or skin of prey, over a time period of less than 3 ms (Tardent and Holstein, …

What is the difference between cnidocytes and nematocysts?

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 difference between polyp and medusa?

In the phylum Cnidaria, which includes jellyfish and sea anemones, polyp and medusa are two different stages of the life cycle.
Difference Between Medusa and Polyp
PolypMedusa
Polyps are sessileMedusae are mobile
Shape
Polyps possess a tubular shapeMedusa has a bell-shaped body
Sep 29, 2020

What is the relationship between tentacles and cnidocytes?

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

Can a discharge stinging cell be used again?

They are used only once. New stinging cells are then formed from nearby cells.

What are medusa and 11 polyps?

Some species of Cnidaria have both stages i.e polyp and medusa, example: Hydrozoa. Some other examples of cnidarians are corals, sea anemones, jellyfish, hydroids, etc.

Polyp and Medusa: Major Differences.
PolypMedusa
1. They are sessile in nature.1. They are mostly free-swimming in nature.

Is Adamsia a polyp?

Aurelia (Medusa) and Adamsia (Polyp) are examples of Coelenterata Phylum.

What is the polyp stage?

Polyp is a sessile life cycle stage of the species belonging to the Cnidaria phylum. Adult corals and sea anemones are examples of polyps. A polyp is formed by a tube with a mouth surrounded with tentacles, referred to as a “head”, and is attached to the bottom with a foot-like disk.

Are polyps benign?

Polyps are benign (non-cancerous) growths, but cancer can start in some types of polyps. These polyps can be thought of as pre-cancers, which is why it is important to have them removed.

Is medusa free swimming?

The medusa is a free-swimming form; it moves by rhythmic muscular contractions of the bell, providing a slow propulsive action against the water. The other principal body type of the adult cnidarian is the polyp, a stalked, sessile (attached) form.

What has no medusa?

Anthozoa have no medusa stage at all and the polyps are responsible for sexual reproduction.

Can a doctor tell if a polyp is cancerous by looking at it?

We know that the majority of colon and rectal cancers develop within polyps that can be easily detected by screening colonoscopy before they become cancerous. “

Why do you get polyps?

Mutations in certain genes can cause cells to continue dividing even when new cells aren’t needed. In the colon and rectum, this unregulated growth can cause polyps to form. Polyps can develop anywhere in your large intestine.

Can you pass a polyp?

The spontaneous expulsion per rectum of a colorectal polyp is exceedingly rare. Here, we report a rare and unusual case that we believe is the first of spontaneous expulsion of an adenomatous polyp during defecation.

What happens if a polyp is cancerous?

If a polyp has cancerous cells, they will also biopsy nearby lymph nodes to determine if the cancer has spread or metastasized to other areas of the body. In this case radiation, chemotherapy or other therapies may be recommended. Colonoscopy screenings can be life saving!