Sheep Brain Dissection11:25Life Science lab
Sheep Brain Dissection
A sheep brain has the same basic regions as a human brain, although their sizes differ. The cerebrum, cerebellum, and brainstem are the three main parts seen from the outside. The longitudinal fissure separates the cerebral hemispheres. Gyri are the raised folds of the cerebral cortex, and sulci are the grooves between them. The transverse fissure separates the cerebrum from the cerebellum. On the underside, the olfactory bulbs, optic nerves, optic chiasm, pons, and medulla oblongata lead toward the spinal cord. A midsagittal cut follows the midline and shows the corpus callosum, thalamus, hypothalamus, and the arbor vitae inside the cerebellum.
Sheep Brain Dissection11:25Learning sequence
- PrepareRead the guide and complete the pre-lab.
- ObserveWatch the dissection. Follow your teacher's directions with the specimen.
- RecordComplete the observations and drawings on the lab write-up.
In This Lab You Will
Orient the specimen using anterior, posterior, dorsal, and ventral, and tell the sheep's right from its left.
Identify any remaining meninges, then the cerebrum, cerebellum, and brainstem.
Locate the longitudinal fissure, the transverse fissure, gyri, and sulci.
On the ventral surface, find the olfactory bulbs, optic nerves, optic chiasm, pons, medulla oblongata, and any cranial-nerve stumps your teacher assigns.
After the midsagittal cut, identify the corpus callosum, thalamus, hypothalamus, and arbor vitae.
Complete the pre-lab and the lab write-up.
Materials
Preserved sheep brain, dissecting tray, blunt probe, forceps, dissecting scissors, a teacher-approved cutting tool, protective eyewear, gloves, protective clothing, paper towels, colored pencils, and assigned recording materials.
Safety
Wear protective eyewear, gloves, and protective clothing. Keep hands away from your face while working.
Keep the brain supported in the tray. Preserved nervous tissue tears easily. Use a blunt probe to point, and keep fingers out of the cutting path.
Have your teacher demonstrate and supervise the midsagittal cut.
Follow classroom directions for preservatives, storage, and disposal. Wash your hands after cleanup.
Photos & Anatomy References
Select an image to enlarge it. The figures follow the dissection from the outside of the brain to a midsagittal section. The number key is part of each figure.
Labeled photographs from the Mr. E Science sheep brain dissection.