Phylum Platyhelminthes Class Turbellaria Flashcards

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Questions and Answers

What is the phylum of Planaria?

Platyhelminthes (correct)

Annelida

Mollusca

Arthropoda

What are Auricles?

Ear-like lobe with many sensory cells that functions for smell.

What is the pharynx?

Throat that can be protruded through the ventral mouth opening when feeding.

What is the function of the pharyngeal sheath?

Encloses the pharynx and acts as protection. Signup and view all the answers

What does the gastrovascular cavity refer to?

Digestive tract. Signup and view all the answers

What are cerebral ganglia?

Two clusters of nerve cells at the anterior end. Signup and view all the answers

What are nerve cords?

Double row of ganglia connected longitudinally with a cord of nerve fibers. Signup and view all the answers

What do transverse nerves connect to?

Nerve cords. Signup and view all the answers

What are lateral nerves?

Nerves that extend outward from nerve cords. Signup and view all the answers

What are Ocelli?

Eye spots. Signup and view all the answers

What happens to the eggs in the ovaries?

Eggs are fertilized as they are discharged and travel down the oviduct. Signup and view all the answers

What is the function of the oviduct?

Conveys sperm anteriorly and fertilizes eggs posteriorly. Signup and view all the answers

What do yolk glands produce?

Yolk added to eggs. Signup and view all the answers

Where do the testes occur?

Along the whole body. Signup and view all the answers

What is the function of the vas deferens?

Carries sperm posteriorly from testes to vesicles for storage. Signup and view all the answers

What are seminal vesicles?

Simple tubular glands posterior to the urinary bladder of some male mammals. Signup and view all the answers

What does the seminal receptacle do?

Receives sperm from mating partner. Signup and view all the answers

How do planarians rid themselves of undigested food?

Regurgitate it. Signup and view all the answers

Are planarians monoecious or dioecious?

Monoecious. Signup and view all the answers

What might be the advantage of an intestine with three branches?

Better diffusion of food, with no area beyond effective diffusion distance from the food source. Signup and view all the answers

Why do flatworms have cilia on the ventral epidermis but not on the dorsal?

For locomotion. Signup and view all the answers

Study Notes

Phylum Platyhelminthes, Class Turbellaria, Genus Planaria

Phylum Platyhelminthes includes flatworms with soft-bodied characteristics.
Class Turbellaria encompasses mostly free-living species, primarily found in aquatic environments.
The genus Planaria is notable for its regenerative abilities and is often studied in biological research.

Key Anatomical Features

Auricles:
- Ear-like lobes rich in sensory cells, primarily for smell, not hearing.
Pharynx:
- Functions as a throat, can extend through the ventral mouth for feeding.
Pharyngeal Sheath:
- Protective structure surrounding the pharynx, providing physical support.
Gastrovascular Cavity:
- Serves as the primary digestive tract for nutrient processing.
Cerebral Ganglia:
- Clusters of nerve cells located at the anterior end, acting as a rudimentary brain.
Nerve Cords:
- Double row of longitudinally connected ganglia, forming the central nervous system.
Transverse Nerves:
- Connective structures creating a ladder-like organization within the nervous system.
Lateral Nerves:
- Extend outward from nerve cords, contributing to the nervous system's complexity.
Ocelli:
- Simple eye spots that detect light and movement, aiding in navigation.

Reproductive Anatomy

Ovaries:
- Fertilization occurs as eggs pass down the oviduct to be discharged.
Oviduct:
- Transports sperm anteriorly and facilitates posterior fertilization of eggs.
Yolk Glands:
- Produce yolk, which nourishes developing eggs.
Testis:
- Located throughout the body, responsible for sperm production.
Vas Deferens:
- Carries sperm from testes to vesicles for subsequent storage.
Seminal Vesicle:
- Simple tubular glands found posterior to the urinary bladder in various male mammals.
Seminal Receptacle:
- Structure that receives sperm from a mating partner during reproduction.

Digestive and Excretory Processes

Undigested Food Elimination:
- Planarians regurgitate any indigestible remnants from their digestive cavity.

Sexuality and Reproduction

Monoecious Nature:
- Planarians possess both male and female reproductive organs, allowing them to engage in self-fertilization or cross-fertilization.

Adaptations and Functionality

Three-branched Intestine:
- Enhances nutrient diffusion efficiency; minimizes distance between food source and cells.
Cilia on Ventral Epidermis:
- Facilitate movement and locomotion while absent on the dorsal side for streamlined body structure.

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Description

Test your knowledge on the phylum Platyhelminthes and class Turbellaria with these flashcards focusing on the genus Planaria. Each card features key terms and definitions to enhance your understanding of these fascinating organisms. Perfect for biology students looking to deepen their grasp of flatworm anatomy and functions.