Phylum Platyhelminthes and Class Cestoda Vocabulary

This set of vocabulary flashcards covers the general characteristics of flatworms (Phylum Platyhelminthes) and the specific anatomy and species of tapeworms (Class Cestoda) as described in the lecture notes.

Phylum Platyhelminthes

A group of leaf-shaped, oval, or elongated organisms collectively called flatworms, which are dorsoventrally flattened and bilaterally symmetrical.

Tegument

A membrane covered by microvilli that absorbs food from the host's intestine in flatworms.

Flame cell (protonephridium)

The specialized cell used by certain flatworms for an incomplete digestive or excretory system.

Hermaphrodite

Organisms that possess both male and female reproductive organs; all flatworms in this context are hermaphrodites except for Schistosoma species.

Class Cestoda

A class of ribbon or tape-like segmented parasites (tapeworms) whose adults inhabit the small intestines of vertebrates and lack a digestive system.

Scolex

The head or organ of attachment in tapeworms, provided with suckers such as bothria or acetabula, and potentially a rostellum.

Bothrium

A type of sucker found on the scolex of pseudophyllidean tapeworms used for attachment.

Rostellum

A part of the tapeworm scolex that can be armed with hooklets or unarmed.

Neck

The region of growth in a tapeworm located between the scolex and the strobila, containing immature proglottids.

Strobila

The body of the tapeworm consisting of a series of proglottids.

Proglottids

Complete reproductive units of a tapeworm body categorized into three types: Immature, Mature, and Gravid.

Immature Proglottid

The segment nearest to the neck containing undeveloped sexual organs.

Mature Proglottid

The segment of a tapeworm body containing fully mature sexual organs.

Gravid Proglottid

The segment containing fertilized eggs which undergoes the process of apolysis.

Apolysis

The normal process of detachment of the gravid proglottid from the adult tapeworm.

Hexacanth embryo (Oncosphere)

The initial egg stage in the life cycle of Class Cestoda.

Order Pseudophyllidea

A taxonomic order of tapeworms characterized by a spatulate scolex with bothria, such as Diphyllobothrium latum.

Order Cyclophyllidea

A taxonomic order of tapeworms characterized by a globular scolex with four cup-like suckers.

Diphyllobothrium latum

Also known as the Broad or Fish tapeworm; its infective stage for humans is the Plerocercoid Larva.

Sparganosis

A clinical condition caused by the Sparganum larva characterized by painful inflammatory reactions, ocular edema, or CNS symptoms like seizures.

Dipylidium caninum

Commonly known as the Dog and Cat flea tapeworm; infection in humans (often children) occurs via accidental ingestion of infected fleas.

Hymenolepis nana

The Dwarf tapeworm; the smallest tapeworm infecting humans which may not require an intermediate host to complete its life cycle.

Hymenolepis diminuta

The Rat tapeworm, which requires an arthropod intermediate host like a flea or grain beetle to complete its life cycle.

Taenia solium

The Pork tapeworm, acquired by eating undercooked pork, with an infective stage known as Cysticercus cellulosae.

Taenia saginata

The Beef tapeworm, acquired by eating raw or undercooked beef, with an infective stage called Cysticercus bovis.

Cysticercus cellulosae

Commonly called the Bladder Worm; the larval stage of Taenia solium that can lodge in voluntary muscles, eyes, or the brain.

Taenia asiatica

The Asian Taenia, morphologically similar to T. saginata, whose cysticerci develop in the liver and viscera of pigs rather than muscle.

Echinococcus granulosus

Known as the Hydatid worm; the smallest tapeworm consisting of a scolex, short neck, and only $3$ proglottids.

Hydatid cyst

A cyst that develops in different organs and tissues of the host following infection by Echinococcus granulosus.