CENTRAL NERVOUS SYSTEM Dissection of the Sheep Brain Including Midsagittal, Dorsal and Ventral Sections

Midsagittal Section: Cerebrum and Cerebellum Parietal lobe Occiptal lobe Cerebellum Cerebrum Arbor vitae Fornix Frontal lobe Cerebrum consists of two hemispheres, each with 4 lobes: frontal, parietal, occipital, and temporal (lateral view) corpus callosum -commissural fibers joining right and left hemispheres fornix - connects ??? Cerebellum - consists of folia (folds) of gray matter arbor vitae - white tracts in cerebellum Ventricles - filled with cerebrospinal fluid (CSF) lateral - within cerebral hemispheres fourth - between cerebellum and pons Corpus callosum Fourth Ventricle

Midsagittal Section: Diencephalon - Thalamus & Epithalamus Third ventricle Pineal body Diencephalon consists of epithalamus (pineal body and choroid plexuses of 3rd ventricle), thalamus Thalamus Intermediate Mass

Midsagittal Section: Diencephalon - Hypothalamus Mammillary body

Midsagittal Section: Brain Stem Corpora quadrigemina Fourth ventricle Pons Medulla oblongata Midbrain Cerebral aqueduct

Midsagittal Section: Cerebellum and Spinal Cord Arbor vitae Central canal Spinal cord

Dorsal View – Whole Brain Longitudinal Fissure Cerebrum Sulci Gyri Corpora quadrigemina Sulci (sing. sulcus) – grooves between ridges Gyri (sing. gyrus) – ridges Cerebellum Medulla oblongata Spinal cord

Dorsal View – Pineal Body & Corpora Quadrigemina Superior colliculi Inferior colliculi

Ventral View - Anterior Olfactory bulb Olfactory tract Cerebrum Pituitary gland

Ventral View – Optic Nerve and Chiasma Optic nerves Optic chiasma (dura mater partially removed) (dura mater intact)

Ventral View - Posterior Cerebellum Dura mater Medulla oblongata Spinal cord

Ventral View Without Pituitary Dura mater Cerebrum Hypothalamus Midbrain Mammillary body Pons Medulla oblongata Spinal cord

Ventral View Without Pituitary – Cranial Nerves Olfactory bulbs Optic nerves Olfactory tract Optic chiasma Optic tracts Trigeminal nerve (V)