EXCRETORY SYSTEMS AND MECHANISMS
CONTENT
- Excretory Mechanism in Earthworm
- Excretory System in Insects
- Excretory Mechanism in Mammals
Excretory Mechanism in Earthworm
The nephridia is the excretory organ of earthworm. Each segment of the nephridia contains a pair of tubes. Each nephridium is a long coiled tube derived by the growth of ectoderm, and opens into the coelomic fluid of the segment anterior to the nephridiophore. The first part is called the nepridiopore, and it has a minute flattered funnel with the upper lip large than the lower lip. The upper lip is formed mainly of a large central cell which is thickly ciliated on the inner surface of the funnel. The lower lip on the other hand consists of a thickened cluster of small cells which are not ciliated. All the cilia beat into the lumen of the tube. The nephrostome leads into an intrcellular ducts which bears two rows of lateral cilia. Beyond the septum, the tube is narrower and ciliated. It goes into several loops and then becomes the wider brown, ciliated tube which terminates at the nephridiophore.
- NEW: Download the entire term's content in MS Word document format (1-year plan only)
- The complete lesson note and evaluation questions for this topic
- The complete lessons for the subject and class (First Term, Second Term & Third Term)
- Media-rich, interactive and gamified content
- End-of-lesson objective questions with detailed explanations to force mastery of content
- Simulated termly preparatory examination questions
- Discussion boards on all lessons and subjects
- Guaranteed learning
ClassHall Instructor
Wilfred Bassey
Maryam
Zulaikha Momoh
Zainab Ahmadu