Sea Star Dissection Terms

Study Notes

Sea Star Anatomy and Echinoderm Classes

Ampullae: Fluid-filled structures in the water vascular system that help control tube feet movement.
Digestive Glands: Organs in sea stars that assist in breaking down food for absorption.
Ring Canal: Circular canal surrounding the mouth that connects to radial canals, part of the water vascular system.
Gonads: Reproductive organs responsible for producing gametes in echinoderms.
Radial Canal: Channels extending from the ring canal to the tube feet, essential for nutrient and water distribution.
Madreporite: The main entry point for seawater into the water vascular system, located on the dorsal side of sea stars.
Asteroidea: The class that includes the most common sea stars and their relatives.
Aboral Surface: The dorsal side of asteroids, opposite the mouth.
Bilateral Symmetry: Larval echinoderms exhibit bilateral symmetry before developing into radially symmetrical adults.
Dioecious: Echinoidea organisms have separate male and female individuals.
Pentaradial Symmetry: Adults display a unique pattern of radial symmetry with five arms or sections.
Dermal Branchiae: Also known as skin gills, these structures facilitate gas exchange in echinoderms.
Water Vascular System: A hydraulic system providing the pressure needed for tube foot movement.
Five Classes of Echinoderms: Asteroidea, Crinoidea, Echinoidea, Holothuroidea, and Ophiuroidea represent the major classifications.
Crinoidea: Class that encompasses sea lilies and feather stars, characterized by their feathery arms.
Ophiuroidea: Class that includes brittle stars and basket stars, known for their distinct arm movement.
Echinoidea: This class consists of sea urchins and sand dollars, often having a compact body and spines.
Holothuroidea: Class that comprises sea cucumbers, which have elongated bodies and soft, leathery skin.
Tentacles: Modified tube feet in holothuroidea that assist with feeding and manipulation of food.
Respiratory Trees: Unique structures in holothuroidea used for gas exchange and water circulation.
Sticky Tubules: Defense mechanism of holothuroidea that can eject threads from their anus to deter predators.
Eviscerate: A stress response in holothuroidea where they expel internal organs to escape threats.

Chordate Characteristics and Subphyla

Four Chordate Characteristics: Dorsal hollow nerve cord, notochord, pharyngeal slits, and a post-anal tail are essential features of all chordates.
Three Subphyla of Chordata: Include Cephalochordata, Urochordata, and Vertebrata.
Urochordata: Subphylum consisting of tunicates and salps, characterized by a sac-like body.
Tunic: Protective cellulose sac surrounding urochordates, providing structural support.
Sessile: Most adult urochordates remain fixed in one place, lacking locomotion.
Pharyngeal Slits: Only characteristic retained in adult urochordates, aiding in filter feeding.
Filter Feeders: Urochordates and cephalochordata both acquire nutrition by filtering small particles from water.
Tubular Heart: Urochordates possess a heart that reverses blood flow periodically.
Two Types of Siphons: Urochordates have incurrent and excurrent siphons for water intake and expulsion.
Cephalochordata: Subphylum including lancelets, small marine organisms that exhibit chordate features throughout their lives.
Wheel Organ: A ciliated feeding structure in cephalochordata that helps capture food particles.
Oral Cirri: A filter structure that prevents sediment from entering the mouth of cephalochordates.
Atriopore: The exit for water in cephalochordates, allowing waste and excess water to flow out.

Description

Test your knowledge on the anatomical terms associated with sea star dissection. This quiz covers key components such as ampullae, digestive glands, and more. Perfect for biology students looking to deepen their understanding of echinoderm anatomy.