Question

The archinephric kidney is present in
A. Larvae of vertebrates
B. Lampreys
C. Hagfish
D. Tadpole

Answer 1

Hint: The archinephric kidney is a primitive structure and therefore seen in simple organisms.

Complete answer:
The archinephric types of the kidney are the excretory system present in primitive vertebrates. It consists of a pair of archinephric ducts present dorsally inside the body cavity and extends the coelomic length.
The archinephric kidney is found only in the living vertebrates which include the larvae of Myxine or Hagfish and some amphibians.

Additional Information:
- The archinephric kidneys have segmentally arranged tubules, a single pair per body segment.
- Each tubule opens individually into a coelom by a peritoneal funnel and nephrotome.
- Near the funnel is an external glomerulus without Bowman’s capsule, suspended in the coelom.
- The tubules together from each kidney open into a common longitudinal duct known as Wolffian or archinephric duct, which later gets attached to the cloaca.
- The external glomerulus is a small knot or cluster of capillaries which is situated closely to the nephrotome.
- The kidney structure in present-day vertebrates kidneys is of three types pronephros, mesonephros, and metanephros all of which have been derived from the archinephric type.
- Pronephros: It is the most primitive and present in the embryonic stage of all vertebrates and is non-functional in adults. It develops from the anterior portion of the nephrotome. Only 3 to 15 uriniferous tubules are present, one pair in one segment.
- Mesonephros develops from the middle portion of the nephrotome after the degeneration of the pronephros.
- Metanephros kidney is the functional kidney in amniotes, developed from the posterior portion of the nephrotome behind the mesonephros.

So, the correct answer is, ‘archinephric kidney is present is the larvae of vertebrates’

Note: The archinephric kidney is only present in the larval stages of primitive invertebrates like myxine or hagfish, but in the adults, it is either of pronephric, mesonephric or metanephric type.