Biology · Excretory Products and Their Elimination · NEET
No, and NTA loves this trap. Malpighian TUBULES are thin thread-like excretory structures of insects (cockroach) that open into the gut. The Malpighian CORPUSCLE (or Malpighian body) is the filtering part of a human nephron = glomerulus + Bowman's capsule. Same scientist name, totally different organ and animal. Do not mix them in a match-the-column question.
The main excretory organ is the Malpighian tubules. But NCERT-level questions also count uricose glands, nephrocytes and the fat body as structures that accumulate and help eliminate nitrogenous waste (uric acid). Reproductive glands like the phallic gland and collaterial glands are NOT excretory. This is exactly what NEET 2023 tested.
The cockroach is uricotelic ONLY. As an insect it excretes nitrogenous waste as uric acid in the form of a dry pellet or paste with minimum loss of water. This water-saving is an adaptation to terrestrial life. NEET 2023 asked this directly, and the answer is 'Uricotelic only', not ureotelic or a combination.
Both are tubular invertebrate excretory structures, but Malpighian tubules belong to insects (cockroach) and open into the gut, removing uric acid. Nephridia belong to earthworm and other annelids and open to the outside or gut. Flame cells (protonephridia) belong to flatworms. NEET match-the-column PYQs pair Periplaneta with the insect apparatus and Pheretima (earthworm) with nephridia.
They float in the haemolymph (insect body fluid) at one end, absorbing wastes from it, and open into the alimentary canal (at the junction of midgut and hindgut) at the other end. So waste (uric acid) leaves along with the faeces. There is no closed blood filtration like in a human glomerulus.
The Cockroach is :
In cockroach, excretion is brought about by A. Phallic gland B. Uricose gland C. Nephrocytes D. Fat body E. Collaterial glands. Choose the correct answer:
Match List I with List II: A. Taenia B. Paramoecium C. Periplaneta D. Pheretima with I. Nephridia II. Contractile vacuole III. Flame cells IV. Uricose gland
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Malpighian tubules are thin, thread-like excretory structures of most insects, including the cockroach. They remove nitrogenous wastes (mainly uric acid) from the haemolymph and help in osmoregulation. One end floats in the body fluid; the other opens into the gut.
The main excretory organ of the cockroach is the Malpighian tubules. NCERT-level questions also include uricose glands, nephrocytes and the fat body as structures that store and help remove nitrogenous waste.
Insects like the cockroach excrete uric acid as a nearly dry pellet or paste. Uric acid needs very little water to be removed, which conserves body water, an important adaptation for surviving on land.
Malpighian tubules of insects open into the gut and excrete uric acid, working with the haemolymph. The human kidney uses nephrons with a Malpighian corpuscle (glomerulus + Bowman's capsule) and excretes urea as urine. Do not confuse Malpighian tubule with Malpighian corpuscle.
Besides removing waste, Malpighian tubules regulate water and salt balance in the cockroach. By controlling how much water is reabsorbed before waste leaves through the gut, they keep the internal fluid balance stable.
