Now let's look at the cross section of the sheet brain. Once you have observed the external structures of the cerebrum and the cerebellum and the brain stem and the inferior portion of the sheet brain, you want to cut the sheet brain in half right along that longitudinal structure. Once you make an equal mid-saggital plane of dissection, observe the structures. Here we can see deep two the cerebell cortex, you have this white matter that connects the two cerebell hemispheres. This is referred to as the corpus colosum. The corpus colosum is also going to contain the lateral ventricles that are deep to it. Here, going through this membrane, the septum polysidum separates the lateral ventricles, ventricles 1 and 2 that are going to contain the cerebral spinal fluid. The lateral ventricles will then continue to flow that fluid through the coroid plexus here and then around this intermediate mass. Once they go around the intermediate mass, we have the third ventricle. The third ventricle goes above and below the intermediate mass. This intermediate mass is where we find the thalamus. Below the thalamus, we come down and there is an approximate area here referred to as the hypo thalamus. As we saw before, the hypo thalamus will connect by an infodibulum to the pituitary gland. This sheep specimen does not have the pituitary gland attached. Here, posterior to the corpus colosum and the thalamus, we see another gland. This is the pineal gland. The pineal gland contains melatonin to regulate cyclic activity, such as sleep. The posterior to the pineal gland, we also have the corporequadria gemina. The corporequadria gemina has four sections. Here, we can see two parts, the superior coliculus and the inferior coliculus. There is one set on each side of the brain, a left and a right. Here, we see the superior coliculus and the inferior coliculus. The cerebrospinal fluid that flows through the third ventricle will continue on through this little channel that looks like a riverbed or groove. This is referred to as the cerebral aqueduct. The cerebral aqueduct will continue on and once we continue to move that fluid below the cerebellum, we have the fourth ventricle. Here, in the cerebellum cross section, we can see a beautiful tree-like structure. This white matter is referred to as the arbor vita. The arbor vita is going to have folia extensions near the outskirts of this cortex. As we continue on from the fourth ventricle, the cerebral spinal fluid will flow into the central canal. We can see a darkened area here, appearing to be the central part of the spinal cord. Once again, we can see a cross section, medial view of the medulla album data and the ponds. Here, we can also see a medial view of the optic chiasm. This is the center for the crossing over of the optic nerves. Let's review this again. On a different specimen, we can see corpus colasum, septum polysidum separating the lateral ventricles. The third ventricle goes around the thalamus. The hypothalamus is below the thalamus and connects by infantibulum to the pituitary gland, which we see here. Here, this gland is the pineal gland, posterior to the corpus colasum and the thalamus. We can also see two sections of the corpus quadrugemina, superior kilicolis and inferior kilicolis. The third ventricle travels through the cerebral aqueduct and continues to pick up fluid joining with the fourth ventricle. This fluid continues to flow out through the central canal into the spinal cord. These tree-like branches in the cerebellum are referred to as the arbavita. Here, I can see the optic chiasm, the ponds and the medulla alvangada.