Monday July 20
Sheep Brain Dissection
Based on Michael Peters lab manual
Instructors: Sonal Jhaveri, Senior Scientist, Department of Brain & Cognitive Science
Mandana Sassanfar, Instructor, Department of Biology
Work in pairs. You should wear goggles, gloves and a lab coat and work under the hoods.
Station set up.
1) Set up a diaper on the bench. Set up the dissection tray on the diaper. Obtain dissection instruments: Scalpel, razor, scissors, scooping instrument, and twisters.
2) Obtain a sheep brain and place in the dissection tray
3) Orient the opening of the vent over the brain
Start your observations:
- Orient the brain: Identify the dorsal, ventral, anterior (frontal) and posterior positions.
- Observe the brain: It should still have the stem and 3 protective layers (meninges) attached. But your particular specimen might have been removed from the skull without care and have a missing or damaged stem and membranes.
- Using a dissecting scissor make an opening in the meninges and cut through to remove them carefully to expose the brain.
- Identify the 3 layers of meninges as you remove them: the dura mater, arachnoid mater, and pia mater.
What do the names mean?
- Lay the brain on its ventral side; Identify the cerebrum, the two cerebral hemispheres, the sulci and gyri, the longitudinal fissure that separates the two hemispheres, the cerebellum, and the vermis that separate the cerebellum into two lobes, the stem and spinal chord.
Which hemisphere is dominant in most people? _________________________
Identify the 4 lobes of the brain.
Name the sulcus that separates the front lobe from the parietal lobe: _________________________
Name the sulcus that separates the frontal and parietal lobes from the temporal lobe:_______________
Which lobe contains the primary visual cortex?___________________________
- Turn the brain around to expose the ventral side.
- Identify the frontal cortex, pituitary gland (if present), the olfactory bulbs and olfactory tracts,
the optic nerves and the optic chiasm, the pons, the medulla oblongata