TABLE OF CONTENTS
Excretory and Nervous System of Nematodes (Roundworms)
The excretory and nervous systems of nematodes (roundworms) are relatively simple but play essential roles in maintaining homeostasis, coordinating body functions, and responding to environmental stimuli. The excretory system is primarily involved in osmoregulation, while the nervous system consists of a nerve ring, longitudinal nerve trunks, and specialized sense organs such as amphids and phasmids.
Excretory System
In nematodes, the excretory system is primarily involved in osmoregulation. It consists of a pair of unbranched lateral vessels that open through an excretory pore. The excretory pore is situated a short distance behind the anterior extremity.
Nervous System
The nervous system consists of a number of ganglia connected by nerve fibers, forming a nerve ring around the esophagus. From this central nerve ring, six nerve trunks extend into the anterior and posterior parts of the body.
Sense Organs
- Amphids
- Phasmids
- Cervical Papillae
- Genital Papillae
1. Amphids
A pair of depressions situated on either side of the head end is called amphids. They are well supplied with nerve fibers and function as chemoreceptors.
2. Phasmids
A pair of depressions found on either side of the tail end is called phasmids. Earlier, they were used for the classification of nematodes.
3. Cervical Papillae
A pair of finger-like pointed processes found in the cervical region is called cervical papillae. e.g., Oesophagostomum.
4. Genital Papillae
A pair of papillae found in the vulvar region of females.
