Biology · Structural Organisation in Animals · NEET
A frog has 10 pairs of cranial nerves. Humans (and other mammals) have 12 pairs. NEET loves this swap. NCERT clearly says: 'There are ten pairs of cranial nerves arising from the brain.' If a question gives 'twelve pairs' for frog, it is wrong.
Optic lobes belong to the MID-BRAIN (one pair of optic lobes). The hind-brain has only the cerebellum and medulla oblongata. A common trap statement puts optic lobes in the hind-brain — that is false.
In the FEMALE frog, the ureters and the oviduct open SEPARATELY into the cloaca. In the MALE frog, the ureter acts as a urinogenital duct (it carries both urine and sperms). This male vs female difference is a favourite NEET point.
The frog is UREOTELIC — it excretes urea. Excretory wastes are carried by blood to the kidney, where urea is separated and excreted. Do not confuse this with ammonotelic aquatic animals like bony fishes.
Each frog kidney is made of many structural and functional units called uriniferous tubules, which are the nephrons. So 'uriniferous tubule' = nephron. The kidneys are compact, dark-red, bean-like structures lying on both sides of the vertebral column, a little posteriorly in the body cavity.
Fore-brain (olfactory lobes, paired cerebral hemispheres, unpaired diencephalon), mid-brain (a pair of optic lobes) and hind-brain (cerebellum and medulla oblongata). The medulla passes through the foramen magnum and continues as the spinal cord.
Choose the correct statements regarding frog's anatomy: A. Hepatic portal system is the special venous connection between liver and intestine. B. There are twelve pairs of cranial nerves arising from the brain. C. The ureters and oviducts open separately into the cloaca in female frogs. D. Hind-brain consists of cerebellum, medulla oblongata and optic lobes. E. Sinus venosus joins the right atrium of heart.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
A frog has one pair of kidneys. They are mesonephric, compact, dark-red, bean-like structures on both sides of the vertebral column, made of many nephrons (uriniferous tubules).
Blood carries urea to the kidney, where it is filtered. Two ureters emerge from the kidneys; in the male these act as urinogenital ducts and open into the cloaca. The thin-walled urinary bladder (ventral to the rectum) also opens into the cloaca.
The brain is divided into fore-brain (olfactory lobes, cerebral hemispheres, diencephalon), mid-brain (a pair of optic lobes) and hind-brain (cerebellum and medulla oblongata).
Because it has three easy trap points — 10 (not 12) cranial nerves, optic lobes in the mid-brain (not hind-brain), and the CNS/PNS/autonomic split. A single Match/statement question can test all of these at once, as in NEET 2026.
