Phylum Annelida Notes (copy)

Phylum Annelida

The phylum that includes segmented worms such as earthworms, polychaete worms, and leeches, found in various environments.

Metamerism

The characteristic segmentation of annelids, where the body is divided into repeating segments that contain elements of circulatory, nervous, and excretory systems.

Setae

Bristle-like structures that project from the cuticle of most annelids (except leeches) to aid in movement.

Coelom

A true body cavity present in annelids, separated by septa and lined by mesoderm.

Polychaetes

A subgroup of annelids that are mostly marine, exhibiting various niches and behaviors.

Oligochaetes

A subgroup of annelids that includes freshwater segmented worms, such as earthworms, which have setae but no parapodia.

Leeches

A subgroup of annelids with fewer segments and suckers for attachment, some of which are obligate parasites.

Metanephridia

A type of excretory organ in annelids that functions similarly to nephrons in mammals.

Closed Circulatory System

A circulatory system in earthworms where blood is contained in vessels, with dorsal and ventral vessels connected by circular vessels.

Hirudo medicinalis

The scientific name for the medicinal leech, known for its therapeutic properties and use in hirudotherapy.

Hirudotherapy

The use of leeches for therapeutic purposes, particularly in treating inflammation and preventing hematoma after surgical procedures.

Clitellum

A specialized glandular structure in earthworms that produces a slime tube for egg and sperm transfer during reproduction.