Question

The excretory organs in prawn are (a) Malpighian tubules (b) Nephridia (c) Kidneys (d) Green glands or antennal gland

Short answer

The excretory organs in prawns are the green glands or antennal glands.

Step-by-step solution

Understanding the question

The question asks for the excretory organs in a prawn. Let's look at each option individually, to understand what function they have, starting with malpighian tubules, then nephridia, kidneys, and finally, green glands or antennal gland.

Analyzing the options

Malpighian tubules are found in insects. They are their primary excretory and osmoregulatory system. Nephridia are invertebrate organs which occur in pairs and perform similar functions to kidneys, these are present in many invertebrates like earthworms. Kidneys are typical of vertebrates so we can exclude this option. Lastly, Green glands or Antennal glands are excretory organs in crustaceans like prawns.

Deciding the correct Answer

After analyzing the options, the correct answer is Green glands or Antennal gland, as they are found in prawns and perform an excretory function.

Key concepts

Green Glands

Green glands are crucial excretory organs in prawns and other crustaceans. You might wonder, what exactly are green glands? They are named for their greenish color and are comparable to kidneys in humans.
Essentially, they are responsible for maintaining the internal chemical balance of the prawn. Each prawn has a pair of these glands, located near the base of the antennae.
The role of green glands is to filter out metabolic waste from a prawn’s bloodstream. They then expel these wastes to the surrounding water, helping to keep the prawn healthy.
Since prawns live in aquatic environments, their green glands are adapted to extract and remove excess salts and waste, which is essential for osmoregulation.

Antennal Glands

Closely related to green glands, antennal glands perform similar excretory functions in prawns. Often, the terms green glands and antennal glands are used interchangeably, but they refer to the same organ.
Located near the prawn’s head, at the base of its antennae, antennal glands play a vital role in waste removal. They are a key part in the prawn’s ability to adapt to its aquatic surroundings.
These glands are vital for filtering blood, allowing prawns to manage salt and water levels effectively. By excreting waste and balancing electrolytes, antennal glands are indispensable in the everyday functioning of crustaceans.

Excretory Organs in Crustaceans

Crustaceans, a broad group that includes prawns, crabs, and lobsters, have specialized excretory organs like the green glands. These organs are tailored to their aquatic habitats.
Here are some characteristics of crustacean excretory systems:

• Centrally located near the base of their antennae.
• Function similar to kidneys in humans, filtering waste from the bloodstream.
• Help in maintaining the chemical balance, especially of salts and other electrolytes.

The excretory system in crustaceans is crucial in allowing these creatures to survive in aquatic environments by handling the osmotic pressure and salt concentration.

Osmoregulation in Invertebrates

Osmoregulation is the process by which organisms maintain fluid and electrolyte balance to ensure proper biological function. In invertebrates like prawns, this process is vital for survival, especially in various aquatic conditions.
Prawns primarily use their green or antennal glands for osmoregulation. These organs adaptively regulate water and salt balance, adapting to fresh or salt water environments.
How do they do this? By adjusting the ion concentration inside their bodies, prawns can thrive in differing levels of salinity. This adaptability highlights their resilience and specialized adaptations for living in fluctuating water conditions.