More mistakes seem to be emerging in textbooks.
Class 10 science textbooks have printed an incorrect diagram of the heart, which does not show the tricuspid and bicuspid valves – important for blood circulation.
More than 16 lakh students have referred to this textbook since it was first published in 2011.
The book is based on the new 2005 syllabus.
The incorrect diagram has been printed on the cover of the textbook as well as on the inside pages.
Experts say the diagram is incorrect because it does not show flap-like structures or valves that ensure blood flow in a single direction.
The tricuspid valve located between the right atrium and the right ventricle prevents the back flow of blood as it is pumped from the right atrium to the right ventricle.
The bicuspid valve controls the flow of blood in one direction through the left side of the heart, especially to prevent blood from going back into the lungs.
“These valves are extremely important while studying the heart. Though I had complained about the mistake to the board in 2011, it has still not been rectified,” said Naresh Tamboli, a retired science teacher.
The textbook also has mistakes in other diagrams.
One diagram shows a hand holding a test tube filled with concentrated hydrochloric acid, while it should have shown the test tube being held with a pair of tongs.
“Handling such acids without tongs can inflict long-lasting burn injuries,” said Tamboli.
The board has blamed the mistakes on negligence by the board of studies for the subject, which has now been suspended as its tenure had ended.
“We will be careful while appointing the new board of studies and in the meanwhile these mistakes will be corrected through the monthly magazine,” said a senior board official.