University:
Missouri State University
Course:
BIO 121 | General Biology I
Academic year:

2019
Views:

330

Pages:

8
Author:

Gironetzbk3n

Ventral Structures PART 2 Sheep brain, ventral side, dura mater partially removed Place the brain ventral side up in the dissecting pan. Remove all dura mater except for a small rectangle that leaves the pituitary and optic chiasma intact. • Take a picture of the ventral view and… • Use the following slides to locate the: optic chiasm, a cranial nerve, olfactory bulbs, pituitary gland, medulla, pons and spinal cord. 1. Frontal Lobe 2. Olfactory bulbs 3. Temporal Lobe 4. Optic Chiasm 10. Pons 12. Medulla Oblongata Not shown: pituitary 15. Optic Nerve (a cranial Nerve) 16. Oculomotor Nerve (a cranial nerve) • Look for the club-like olfactory bulbs on the inferior surface of the frontal lobes of the cerebral hemispheres. • Measure the length of the olfactory bulbs and record. Olfactory Bulbs Sheep Human • This picture, from the visible human project, shows the pathway of optic nerve from the back of the eye through the optic chiasm. • The optic nerve (II) carries sensory input from the retina of the eye to the brain. The X-shaped structure is where the fibers of each optic nerve cross over to the opposite side of the brain. • The optic tracts continue from the optic chiasm toward the occipital lobe – the primary visual center. Pituitary Gland The pituitary gland, which produces important hormones, is a sac-like area that attaches to the brain between the pons and the optic chiasm. The pituitary gland will likely pull off if you remove the dura mater so be careful. At the caudal border of the cerebral peduncles you will find the pons, followed caudal by the medulla oblongata. Finally, the spinal cord extends from the posterior portion of the medulla. The medulla ends (roughly) at the edge of the slightly rounded area, and at the beginning of the spinal canal (identified in the dorsal view). Pons Medulla Spinal cord