Lesson 7 of 11 · 6 min
Excretory system
NCERT §7.2.2
Ms Rao hands Arjun two labelled diagrams, one of a male frog's excretory organs and one of a female's, and says: find the one tube that does two jobs.
The lesson in notes
In short
Nitrogenous wastes are removed by a well-developed excretory system made of a pair of kidneys, the ureters, the cloaca and the urinary bladder.
The kidneys are compact, dark red, bean-like organs placed a little towards the back of the body cavity, one on each side of the vertebral column.
Each kidney is made of many structural and functional units called uriniferous tubules, or nephrons.
In the male, the two ureters coming out of the kidneys also carry sperms, so they act as urinogenital ducts and open into the cloaca.
In the female, the ureters and the oviducts open separately into the cloaca.
A thin-walled urinary bladder lies ventral to the rectum and also opens into the cloaca.
Blood carries the excretory wastes to the kidneys, where they are separated and excreted. The frog excretes urea, so it is ureotelic.