What is the role of the chaetae?

What is the role of the chaetae?

chaeta (pl. chaetae) A bristle, made of chitin, occurring in annelid worms. In the earthworm they occur in small groups projecting from the skin in each segment and function in locomotion. The chaetae of polychaete worms (e.g. ragworm) are borne in larger groups on paddle-like appendages (parapodia).

What animals have chaetae?

A chaeta or cheta (from Greek χαίτη “crest, mane, flowing hair”; plural: chaetae) is a chitinous bristle or seta found in annelid worms, (although the term is also frequently used to describe similar structures in other invertebrates such as arthropods).

What is the function of parapodium?

The fleshy protrusions on the sides of some marine gastropods are also called parapodia. They are particularly well-developed in sea butterflies. Some sea hares use their parapodia to swim. Parapodia can even be used for respiration (similar to gills) or for locomotion.

What is parapodium in zoology?

Parapodia are fundamentally the organs of locomotion used both in creeping and in swimming. Considering they are highly vascularized, they also assist the function of respiration.

What is the difference between setae and chaetae?

The key difference between setae and chaetae is that setae are bristle-like structures present in both vertebrates and invertebrates, while chaetae are chitinous bristle-like structures present in most fungal species.

What is Prostomium in zoology?

Definition of prostomium : the portion of the head of an annelid worm (such as an earthworm) that is situated in front of the mouth.

Do all annelids have chaetae?

Circular as well as longitudinal muscles are located interior to the epidermis. Chitinous hairlike extensions, anchored in the epidermis and projecting from the cuticle, called setae/chaetae are present in every segment. Annelids show the presence of a true coelom, derived from embryonic mesoderm and protostomy.

How is structure of parapodium used in locomotion?

It moves the anterior part, the posterior part or the lateral parts forwards but is able to rotate of 180° on itself. Its locomotion entirely depends on parapodial motions and not on trunk movements.

What is meant by Clitellum?

Definition of clitellum : a thickened glandular section of the body wall of some annelids that secretes a viscid sac in which the eggs are deposited.

What are chaetae in segmented worms?

Chaetae (called also setae) are present in four bundles (two ventral, two dorsal or dorsolateral) on each segment except the first. They are sometimes absent on the genital and some other segments, but they are seldom entirely lacking. Two basic types of chaetae are present: sigmoid and hair chaetae (Figure 21.3).

What is peristomium and prostomium?

Prostomium is a dorsal lobe which is present on the ventral mouth. Peristomium is the first segment of earthworm with a ventral mouth. It overhangs the mouth of an earthworm. It surrounds the mouth opening.

What is the function of prostomium?

The prostomium is a lobe that serves as a covering for the mouth and as a wedge to force open cracks in the soil into which the earthworm may crawl 1. The anterior section of the worm is shown in Figure 1. Another key characteristic is the clitellum, or the collar-like structure near the front of worm’s body.