NEMATODA

• Nematoda is also known as roundworms
• nematoda's body are bilaterally symmetrical
• nematoda's are cylindrical in shape
• nematoda have complete digestive system
• nematoda's body is covered by collagenous (protein) cuticle
• nematoda's are free-living or parasitic
• nematoda's body are Pseudocoelomate and triploblastic
• pseudocoelomate means that the body cavity is not completely enclosed by a membrane
• triploblastic means that the embryo has three layers of cells
• Nervous System of nematoda: Consist of a ring of nerve tissue (nerve ring) around the pharynx and one or more nerve cords running along the length of the body.
• 1/2 Sensory structure of nematoda:

  ❑ Amphids

  ✓ Located near the anterior end of the body.

  ✓ Involved in chemoreception and mechanoreception

  ✓ Allows to detect and respond to changes in their environment.
• 2/2 Sensory structure of nematoda:

  ❑ Phasmids

  ✓ Located near the posterior end of the nematode's body.

  ✓ Associated with chemosensation

  ✓ Allows to detect environmental cues, including potential mates, food sources, and predators.
• 1/2 Digestive and Excretory Organs:

  ❑ Stylet

  ✓ A piercing mouthpart some plant-parasitic nematodes.

  ✓ Used to puncture plant cells and extract nutrients from the host tissues.

  ✓ It is a specialized structure that enables these nematodes to feed on plant sap.
• 2/2 Digestive and Excretory Organs:

  ❑ Excretory ducts and glands

  ✓ Helps regulate the nematode's internal fluid balance and remove metabolic wastes from the body.
• Reproductive organs

  ❑ Spicules

  ✓ A paired copulatory structures of male nematodes.

  ✓ Spicules are inserted into the female's reproductive tract during mating and aid in the transfer of sperm.

  ✓ The size, shape, and structure of spicules vary among different nematode species.
• Muscular Layer:

  ❑ Nematodes have longitudinal muscles that run along the length of their bodies.

  ❑ These muscles allow nematodes to move by contracting and relaxing in a wave-like motion.
• Sexual Reproduction (Internal Fertilization)

  • Roundworms reproduce sexually.

  • They are dioecious
• dioecious means having male and female parts on separate animals of the same species