Nematoda

• Dioecious: Having distinct male and female individuals.

• Pseudocoelom: A body cavity not completely lined with mesoderm, found in nematodes.

• Complete digestive tract: Digestive system with both a mouth and an anus.

• Hydrostatic skeleton: Fluid-filled pseudocoelom that provides support and movement.

• Genus: Ascaris: A genus of parasitic roundworms, often used in dissection.

• Male vs. female (external): Males are generally smaller and have a curved tail; females are larger and straight.

• Lateral lines: Excretory canals visible on the sides of nematodes.

• Dorsal and ventral nerve cords: Main components of the nervous system running along the back and belly.

• Testis: Male reproductive organ producing sperm.

• Vas deferens: Tube that transports sperm from the testis.

• Seminal vesicle: Stores and releases sperm during reproduction.

• Ovaries: Female reproductive organs producing eggs.

• Oviducts: Tubes that carry eggs from ovaries to the uterus.

• Uterus (uteri = plural): Where fertilized eggs develop.

• Vagina: Opening for the reproductive tract in females.

• Genital pore: External opening for reproductive and sometimes excretory functions.

• Pharynx: Muscular organ for sucking in food.

• Intestine: Tube for nutrient absorption.

• Cuticle: Tough, flexible outer covering.

• Epidermis: Layer underneath the cuticle that secretes it.

• Longitudinal muscles: Muscles running lengthwise, allowing thrashing movement.

CHAPTER 14: Phylum Arthropoda

• Jointed appendages: Legs, antennae, and other structures with joints for mobility.

• Segmented body: Body divided into repeating segments.

• Exoskeleton: Hard outer covering made of chitin for protection and support.

• Molting: Shedding of the exoskeleton to allow growth.

• Coelom: True body cavity fully lined with mesoderm.

More Arthropod Terms

• Hemocoel: Body cavity filled with hemolymph (blood-equivalent fluid).

• Open circulatory system: Blood not entirely contained in vessels.

• Cerebral ganglia: Brain-like clusters of nerve cells.

• Ventral nerve cord: Nerve cord running along the belly side.

• Gills: Organs for gas exchange in aquatic arthropods.

• Book lungs: Respiratory structures with stacked plates in arachnids.

• Tracheae: Air tubes used for breathing.

• Spiracles: Openings on the body for air intake.

Subphyla and Classes

• Subphylum Chelicerata
  

  • Class Merostomata: Horseshoe crabs.

  • Class Arachnida: Spiders, scorpions, ticks.

• Subphylum Myriapoda
  

  • Class Chilopoda: Centipedes.

  • Class Diplopoda: Millipedes.

• Subphylum Crustacea
  

  • Class Malacostraca: Crabs, lobsters, shrimp.

• Subphylum Hexapoda
  

  • Class Insecta: Insects.