Brain & Cranial Nerves Lab
BIOL 103 Fall 2022
Brain Models
Use PAL > Anatomical Models > Nervous System > CNS or diagrams from your notes or
Chapter 12 to help you identify structures of the brain and cranial nerves.
External View (1, 4, 5, 12, 13)
Cerebrum/cerebral hemispheres
Gyri & sulci
Longitudinal fissure
Central sulcus
Lobes: frontal, parietal, temporal & occipital
Olfactory bulb & olfactory tract
Optic chiasma, optic nerves & optic tracts
Mammillary body
Cerebellum
Corpora quadrigemina: superior & inferior colliculi
Brain stem: midbrain, pons & medulla oblongata
Internal View (2, 3, 7, 8, 9,
Corpus callosum
Fornix
Diencephalon: thalamus, epithalamus (pineal gland) & hypothalamus
Ventricles: lateral, 3rd & 4th
Septum pellucidum
Cerebral aqueduct
Arbor vitae
Cranial Nerves (6)
Olfactory nerve (CN I)
Optic nerve (CN II)
Oculomotor nerve (CN III)
Trochlear nerve (CN IV)
Trigeminal nerve (CN V)
Abducens nerve (CN VI)
Facial nerve (CN VII)
Vestibulocochlear nerve (VIII)
Glossopharyngeal nerve (IX)
Vagus nerve (X)
Accessory nerve (XI)
Hypoglossal nerve (XII)
Sheep Brain Dissection
Use PAL > Cat > Nervous System > Slides 4 - 10 to help you identify structures of the sheep
brain.
1. Carefully remove dura mater - this is the thickest and most superficial of the brain
meninges (membranes).
2. Locate and identify all external structures listed above in “External View” (PAL Slides 7 9).
3. Gently pull the cerebellum inferiorly to expose the structures of the dorsal midbrain.
Locate and identify the structures of the dorsal midbrain (PAL Slide 10).
4. Make a midsagittal section through the entire cerebrum, cerebellum and brainstem (PAL
Slide 4 - 6).
5. Locate and identify all internal structures listed above in “Internal View” (PAL Slide 4 - 6).
6. As you locate the 3rd ventricle, see if you can find its choroid plexus - this is a cluster of
blood vessels that make CSF.
7. Choose one cerebral hemisphere and make a coronal cut near the central sulcus.
8. Observe the pattern of gray and white matter inside.
9. Preserve your sheep brain in a ziploc bag and store in your blue bin in the cold room.