Protostomes Flashcards

Flashcards covering key vocabulary and concepts related to protostomes, including body plans, phyla characteristics, and medical connections.

Acoelomate

An animal that lacks a coelom, with the space between the digestive tract and outer body wall filled with solid tissue.

Pseudocoelomate

An animal with a pseudocoelom, a body cavity partially lined with mesoderm and endoderm.

Coelomate

An animal with a true coelom, a fluid-filled body cavity completely lined by mesodermal tissue.

Cephalization

The evolutionary trend where nervous tissue concentrates at the anterior (front) end of the body, forming a head region.

Bilateral symmetry

A body plan where an organism can be divided into two mirror-image halves along a single plane.

Protostomes

Animals in which the blastopore (first opening during development) becomes the mouth, and the anus forms later.

Efficient movement (Segmentation)

Localized muscle control, improving flexibility and mobility due to body segments.

Redundancy (Segmentation)

Repeated organs in each segment providing backup.

Specialization (Segmentation)

Segments can evolve to perform specialized functions.

Complete digestive tract

A digestive tract with both a mouth and an anus.

Flame cells

Specialized excretory cells in flatworms that aid in osmoregulation and waste removal.

Tapeworms

Parasitic flatworms lacking a digestive system, absorbing nutrients directly through their skin.

Liver flukes

Parasitic flatworms infecting the liver, bile ducts, and gallbladder, relying on nutrient absorption from host tissue.

Mollusk Head

Typically contains sensory and feeding structures.

Mollusk Foot

A muscular structure used for movement, attachment, or burrowing in mollusks.

Mollusk Visceral Mass

Contains the internal organs, including the digestive, reproductive, excretory, and respiratory systems.

Mollusk Mantle

A protective layer of tissue that covers the mollusk’s body and secretes the shell.

Mollusk Ctenidia

Gills found in many mollusks used for gas exchange.

Mollusk Radula

A toothed organ used by many mollusks to scrape, cut, or grind food.

Mollusk Nephridia

Excretory organs in mollusks that filter and remove nitrogenous waste.

Open circulatory system (Mollusks)

A circulatory system where blood is not always confined to vessels and flows freely through body cavities.

Snails

The first intermediate host in the life cycle of Clonorchis sinensis (Chinese liver fluke).

Increased Mobility (Annelids)

Fine control of movement, improves flexibility and helps annelids move more efficiently.

Specialization of Segments (Annelids)

Different segments of the body can become specialized for different functions.

Redundancy and Resilience (Annelids)

If one segment is damaged, others can continue to function, making the organism more resilient.

Metanephridia

Paired organs located in each body segment of annelids that filter waste and regulate water balance.

Nephrostome

A ciliated funnel that draws in coelomic fluid from the body cavity in annelids.

Closed circulatory system (Annelids)

A circulatory system where blood is confined to vessels.

Cerebral ganglion

A centralized brain in annelids, located in the head.

Leeches

Used in modern medicine for their blood-sucking properties; secrete hirudin, an anticoagulant.

Pseudocoelomates (Nematodes)

The body cavity that nematodes possess.

Complete digestive system (Nematodes)

Possess two openings: a mouth for ingestion and an anus for expelling waste.

Elephantiasis

Transmitted to humans through the bite of infected mosquitoes, causing severe swelling and thickening of the skin.

Pinworms

Infect humans primarily through ingestion of eggs from contaminated food, water, or surfaces.

Hookworms

Transmitted when larvae in contaminated soil penetrate the skin.

Trichinella

Contracted by humans through consumption of undercooked or raw pork or wild game infected with larvae.

Arthropod Exoskeleton

A rigid external covering made of chitin, providing structural support and defense.

Segmentation and Specialization (Arthropods)

The bodies of arthropods are segmented, and each segment can be specialized for specific functions.

Metamorphosis

A process where arthropods transition through distinct life stages.

Tagmata

Specialized body regions formed by the fusion of multiple segments in arthropods.

Ommatidium

One of the individual, functional units that make up the compound eyes of arthropods.

Ocelli

Simple eyes found in many arthropods that detect light intensity.

Malpighian tubules

Excretory organs found in insects and some arachnids, used for the removal of nitrogenous wastes and osmoregulation.

Chelicerae

Mouthparts found in arachnids used for feeding, defense, and sometimes reproduction.

Carapace

A hard, protective exoskeletal covering found in some arthropods, such as crustaceans.

Tracheae (Insects)

Tubes that transport air directly to tissues and cells in insects.

Book lungs (Arachnids)

Stack-like structures consisting of thin, leaf-like layers where gas exchange occurs in arachnids.

Gills (Crustaceans)

Structures adapted to extract oxygen from water, often located under the carapace in crustaceans.

Open circulatory system (Arthropods)

A circulatory system where blood flows freely through the body cavity.

Chelicerata

Organisms with chelicerae for feeding and defense.

Acari

Mites and ticks with specialized mouthparts for feeding; many are ectoparasites.

Araneae

Spiders that have fangs and venom for capturing prey; possess spinnerets to produce silk.

Crustacea

Crabs, lobsters, and shrimp with a calcified exoskeleton.

Hexapoda

Insects that have three body segments and three pairs of legs.

Myriapoda

Centipedes and millipedes that have many body segments with one or two pairs of legs per segment.