What is the Difference Between Integumentary Pharyngeal and Septal Nephridia?

Integumentary, pharyngeal, and septal nephridia are excretory structures found in earthworms. They are located in different segments of the earthworm's body and excrete waste in the form of urine. The main differences between these nephridia are:

1. Position: Integumentary nephridia occur on all segments except the first two, while pharyngeal nephridia occur in the 4th, 5th, and 6th segments, and septal nephridia occur between the 15th and 16th segments.
2. Nephrostome: Septal nephridia have a nephrostome, which is an elliptical mouth-like opening leading into an intracellular canal. This structure is not present in integumentary or pharyngeal nephridia.
3. Location: Integumentary nephridia are attached to the inner side of the body wall, pharyngeal nephridia lie on the sides of the gut in 3 paired groups, and septal nephridia are attached to the septa.
4. Size: Integumentary nephridia are the smallest, septal nephridia are the largest, and pharyngeal nephridia are of intermediate size.
5. Type of excretion: Both septal and pharyngeal nephridia are enteronephric, meaning they excrete waste into the alimentary canal. Integumentary nephridia, on the other hand, are ectonephric, removing metabolic wastes from the blood.

Comparative Table: Integumentary Pharyngeal vs Septal Nephridia

Integumentary, pharyngeal, and septal nephridia are found in earthworms and serve as the main excretory structures. They are located in different segments of the earthworm's body and excrete waste in the form of urine. Here is a table highlighting the differences between integumentary pharyngeal and septal nephridia:

In summary, integumentary nephridia are found throughout the earthworm's body (except for the first two segments), pharyngeal nephridia are located in the 4th, 5th, and 6th segments, and septal nephridia are situated between the 15th and 16th segments. Pharyngeal nephridia have ciliated canals in their lumen, while septal nephridia have a nephrostome. Integumentary nephridia are associated with the integument (skin), pharyngeal nephridia are associated with the pharynx, and septal nephridia are associated with the septum.