This document outlines a sheep brain dissection lab. It begins by comparing sheep and human brain structures like the olfactory bulb and cerebellum. Students will dissect a preserved sheep brain to identify structures like the cerebrum, cerebellum, ventricles, hippocampus, and cranial nerves. They will make mid-sagittal and coronal cuts, diagramming their findings. The goal is to study sheep brain anatomy and compare it to human functions.

1. College Level Design: Tim Cannon
http://academic.scranton.edu/department/psych/sheep/newsheep/ welcome2.html
Edited by Dr. S.C. Wache

2. Goal:
We will compare sheep brain structures with human brain structures.
Compared to human cerebrum a human’s olfactory bulb is much shorter than
sheep olfactory bulbs compared to the sheep cerebrum. Human cerebellum is
bilobed, sheep cerebellum is not.
First, we will learn body positions applied to the whole sheep brain.
We will do two sections: one group will do a mid-sagittal cut, the other a
coronal cut.
Use the mid-sagittal section to find your location through each consecutive
coronal section.

3. Methods and Materials:
We will be dissecting a preserved adult sheep brain.
Our dissection kit contains a scalpel, a fine tipped pair of scissors, a blunt
metal probe, a fine tipped forceps, a blunt-tipped forceps.
It is vital to wear vinyl gloves. It is important to be careful when working with
preservatives. If necessary protect your eyes. Follow OSHA (office of safety
and Health administration) regulations.
Dispose of the dissected specimen as indicated on the MSDA (material safety
and data administration) sheets.
These are some additional web sites where you can obtain more information:
http://labs.ansci.uiuc.edu/rwjohnson/class/braintext.html
University of Scranton, Dissection of the Sheep Brain
University of Scranton, The Sheep Brain Dissection Guide
Michigan State University, Atlas of the Sheep Brain
Interactive Atlases, Digital Anatomist Project
University of Wisconsin, Global Anatomy
University of Utah, Anatomy-Histology Tutorials
Gray Cancer Institute On-line Medical Dictionary

4. Results: The result section should consist of
drawings with labels on the structures that were identified.

5. Sheep brains arrive crudely prepared. You can see fatty
tissue and three membranes, the meninges. The white film
consists of a tough fibrous connective tissue, the dura mater.
Note: Underneath the dura mater, there is the arachnoid mater and the pia mater.
spinal cord

6. (Anterior) (Posterior)
BODY POSITIONS:

8. Diencephalon
LATERAL VIEW
Note the gyri and sulci.

9. SUPERIOR VIEW
Note the longitudinal fissure.

10. INFERIOR VIEW Ventral Midbrain
Pons Medulla
Oblongata
Spinal
Cord
Diencephalon: PITUITARY GLAND

11. Temporal lobe
Insula
Note: Insula - the lobe in the center of the cerebral hemisphere that is situated deeply
between the lips of the sylvian fissure -- called also central lobe, island of Reil
Frontal lobe
Parietal lobe
Lobes of the Sheep Brain Cerebrum
Occipital lobe

12. Pineal gland
CEREBRUM AND CEREBELLUM BENT
APART TO EXPOSE THE DORSAL MIDBRAIN.

13. INFERIOR VIEW
Diencephalon: MAMMILLARY BODIES
Oculomotor Nerve
Abducens
Nerve

14. R- Olfactory Bulb

15. Note the trigeminal
and abducens nerves.

16. Note the abducens,
hypoglossal, and spinal
accessory nerves.
Synonym: Vestibulo-cochlear Nerve

17. Note: You are asked to learn all 12 cranial nerve pairs.

18. ‘Arbor vitae’
or ‘tree of life’
Thalamus
Pineal Gland

19. Corpus callosum
Thalamus
Lateral Ventricle
Third Ventricle
Use this frame to assess your location
in the following coronal sections.
Pineal Gland

20. Lateral Ventricle
Note the gyri and sulci.
FIRST CORONAL SECTION: STARTS WITH THE ANTERIOR PORTION
OF THE FRONTAL LOBE

21. Optic Chiasma
Diencephalon:

22. Pituitary Gland
Thalamus
Hypothalamus
CORONAL SECTION AT THE LEVEL OF THE PITUITARY GLAND
Note: septum pellucidum - the thin double partition extending vertically from the lower surface of
the corpus callosum to the fornix and neighboring parts, separating the lateral ventricles.
Septum pellucidumDiencephalon:

23. Lateral Ventricle
ThirdVentricle
Midbrain (ventral surface) with mammillo-thalamic tract
of fibers connecting thalamus and mammillary bodies
Caudate Nucleus
Caudate nucleus: one of the four basal ganglia in each cerebral hemisphere that comprises a mass of
gray matter in the corpus striatum, forms part of the roof of the lateral ventricle, and is separated from the
lentiform nucleus by the internal capsule

24. Diencephalon:
Pineal gland
(releases melatonin
which controls
circadian rhythm)
Midbrain toward the Superior Colliculi

25. Caudate nucleus: comprises a mass of gray matter in the corpus striatum and forms part
of the lateral roof of the lateral ventricle.
Hippocampus: : a curved seahorse-shaped ridge extending over the roof of the
descending horn of each lateral ventricle, but tissue within the temporal lobe; the
hippocampus is part of the limbic system, and consists of gray matter covered on the
ventricular surface with white matter.
From: www.neuropat.dote.hu/anastru/test2na.htm
(near Pons)
Connecting tissue between colliculi
(cerebral aqueduct)

26. Cerebellum
Corpora quadrigemina
(visible externally on the
dorsal surface when
bending open the brain
between the cerebrum and
cerebellum at a 45o
angle)
Midbrain / near Pons
(ventral surface)

27. Note the H-shaped center of the spinal cord consisting of gray matter.

28. Summary:
We have studied the structures on a preserved sheep brain specimen. We
have learned the functions of such structures using the lecture handout and
comparing to what is known about the human brain function.
We learned body positions applied to the whole sheep brain.
The mid-sagittal cut was helpful in identifying the extension of the lateral
ventricle to the third ventricle. The coronal cuts made it possible to find the
cerebral aqueduct (aqueductus sylvii) that joins the third and fourth ventricles
which house the CSF.
The coronal cut helped in the location of the hippocampus along the roof of the
descending lateral ventricle.