Phylum Platyhelminthes Overview

A group of soft-bodied invertebrates, including flatworms, flukes, and tapeworms.

A body plan that can be divided into mirror-image halves along one axis.

Animals with three germ layers but no body cavity.

Includes Turbellaria (free-living), Trematoda (internal parasites), Monogenea (external parasites), and Cestoda (tapeworms).

Present in Turbellaria, Trematoda, Monogenea; absent in Cestoda.

A level of biological organization where tissues form organs.

Epidermis with cilia that enhances locomotion in certain organisms.

Rod-shaped fused vesicles that assist in protecting and moving organisms by creating a mucus coat.

Structures that produce secretions for attachment and release, aiding in locomotion.

Movement involving ciliated surfaces, muscle contractions, and adhesive organs.

Muscle that runs lengthwise along the body, aiding in movement.

Muscles that encircle the body, contributing to body shape and movement.

Cells that bear the strain of attachment and enable movement by coordinating with muscles.

The simplest nervous system found in some organisms, resembling a nerve net.

Nerve cords that run lengthwise beneath the musculature, typically in pairs.

A cluster of nerve cells serving as a primitive brain, coordinating nervous activity.

Arrangement of nerve cords and commissures resembling a ladder in some nervous systems.

Sensory receptors that respond to touch or physical contact.

An inverted flagellated cell found in protonephridia, aiding in osmoregulation.

A simple excretory system using flame cells for osmoregulation in some invertebrates.

The process of maintaining water and solute balance in organisms.

A small tube-like structure through which fluids pass, involved in excretion.

The motion of flagella that creates negative pressure to draw fluids.

A structure where flame cells sit, allowing selective filtering.

Excretory pores through which modified fluid is eliminated.

Fluid that has been filtered to remove small solutes and impurities.