Question

Where do you find malpighian tubules?

Answer 1

Hint: These tubules are named after Marcello Malpighi. Malpighian tubules are a kind of excretory system.

Complete Answer:
- Malpighian tubules system is an excretory and osmoregulatory unit. It is found in some insects like cockroaches. It consists of branched tubules. These tubules extend from the alimentary canal.
- These are slender tubes which are found in the posterior region of the alimentary canal in arthropods. This system is highly convoluted. They absorb solutes, water and wastes from the surrounding hemolymph.
- The main function of malpighian tubules is excretion of nitrogenous produce and other metabolites. Pre-urine is formed in the tubules due to the transport of wastes and electrolyte through the tubular wall.
- Nitrogenous waste like urea diffuse through the wall and ions like sodium and potassium are transported by an active pump system.
- Pre-urine and digested food merges in the hind gut. The sodium and potassium are absorbed along with water through osmosis. This takes place in the rectum. Uric acid further mixes with faeces and is excreted out.

Additional Information- Some insects have modified malpighian tubules which serve in accessory function. Some insects of genus Arachnocampa have modified and swollen malpighian tubules. They use these tubules to emit blue-green light which attracts its prey. It also helps in removing certain toxic compounds from the hemolymph.

Note: Malpigian tubules are present in most of the insects. Its main function is removal of waste from the hemolymph. It also helps in maintaining the osmotic balance of the body.