Cerebral hemisphereOne of two long smooth bodies, narrow in front and wider behind. A deep groove runs between the two.
Optic lobeOne of two large round bodies in front of the cerebellum. Together they are the widest part of the brain.
CerebellumA narrow band across the brain, just behind the optic lobes. In the frog it is very small.
Medulla oblongataThe hind part of the brain, a widening of the spinal cord. Several pairs of cranial nerves leave its sides.
Olfactory lobeThe front end of the brain, fused with its partner. The nerves of smell begin here.
Olfactory nerveThe first cranial nerve. It runs forward from the olfactory lobe to the nose.
DiencephalonThe part between the hemispheres and the optic lobes. It is also called the thalamencephalon.
Pineal bodyA small outgrowth on the roof of the diencephalon. It is also called the epiphysis.
Fourth ventricleA three-cornered hollow on top of the medulla. Its thin roof carries a web of blood vessels, the choroid plexus.
Spinal cordThe cord that runs back from the brain inside the backbone.
From below 5
Optic nerveThe nerve of sight, from the eye. All of its fibers cross to the other side of the brain.
Optic chiasmThe place where the two optic nerves cross. It lies under the diencephalon.
InfundibulumA flat two-lobed swelling just behind the optic chiasm.
Pituitary bodyA small body behind the infundibulum and partly covered by it. It is also called the hypophysis.
Cranial nervesNerves that leave the brain itself; a frog has ten pairs. Most of them leave from the sides of the medulla.
How this list was compiled: Every name checked on 2026-10-01 in two sources. S. J. Holmes, The Biology of the Frog (1906, public domain), the brain, https://archive.org/details/biologyoffrog01holm. A. Ecker, The Anatomy of the Frog, English edition by G. Haslam (1889, public domain), the brain: general description, https://archive.org/details/anatomyoffrog00ecke. R. W. Hegner, College Zoology (1912, public domain), the brain of the frog, https://archive.org/details/collegezoology00hegn. Licence: own work
The drawing: Drawn for this site on 2026-10-01 from plain geometry; nothing traced. Licence: own work
How it works
This frog brain anatomy quiz names a part and you tap it on the drawing. The brain lies across the page with its front end to the left. Ten parts are asked on the view from above and five on the underside.
Read the full guide
Parts that get mixed up
The cerebral hemispheres are the two long bodies in the front half. The optic lobes are the two large round ones farther back. The cerebellum is the narrow band right behind the optic lobes, easy to take for the front edge of the medulla.
The second view is from below
The two optic nerves come in from the sides, and the patch where they cross is the optic chiasm. Behind the crossing lies the two-lobed infundibulum, then the small oval pituitary body. The short stubs on the sides of the medulla are the roots of the cranial nerves, asked as one part.
The pineal body is the small dot on the diencephalon. The fourth ventricle is the three-cornered patch on the medulla.
An older lab sheet may print thalamencephalon for diencephalon, epiphysis for pineal body and hypophysis for pituitary body.
Questions and answers
Where are the optic lobes on a frog's brain?
On top of the midbrain, just in front of the cerebellum and behind the diencephalon. They are two large rounded bodies side by side.
What is the diencephalon of a frog's brain?
The region between the cerebral hemispheres in front and the optic lobes behind. The pineal body grows from its roof, and the optic chiasm lies on its underside.
Where are the olfactory lobes on a frog's brain?
At the front end, just ahead of the cerebral hemispheres. Unlike the hemispheres, the two olfactory lobes are fused along the midline, so the drawing shows one small rounded part. The two olfactory nerves run forward from it.
Where is the pituitary on a frog's brain?
On the underside, behind the infundibulum and partly covered by it. In the quiz it is the small oval behind the two-lobed body, and it is asked as the pituitary body.