The purpose of this lab is to understand the way that nervous system structures are arranged inside of the brain from the most superior, which would be the cortex or telencephalon to the most inferior, which would be the medulla oblongata. We are observing all the structures in the brain, as well as the protective tissue that surrounds it.
I had to use Primal Pictures, as it was necessary to complete this lab. Once logged in, there is a list of choices to click on as to where you want to go. On the homepage, click on the 3D Head and Neck and then go to the Brain folder. Next click on Meninges to access the pictures. Begin at layer 9. To identify the structures, just click on them. With Primal Pictures, there are different controls on the page that allow us to be able to view the brain, or any structure that we are looking at from different angles and different layers. There is also a summary of the structure that is being looked at. Using the guide that Dr. Poll has provided and Primal Pictures, we are to go through the different structures and gather all the information necessary to complete this lab.
Following the guidelines on our instruction sheet, we were to begin at Layer 9 of the brain, which showed us the meninges. From here, we could see the structures that protect the brain. Brain protection begins with the skull; it is the outermost layer. The three layers of meningeal linings are inferior to the skull. These include the dura mater, which is the outermost layer. It is also the toughest layer and in English is translated to “hard mother.” The dura mater has two layers. Inferior to the dura mater is the arachnoid mater. The most inferior layer of the meninges is the pia mater. It is also the deepest and softest layer. Next we looked at the sinuses that are part of the nervous system in Layer 5. A sinus is a cavity within a bone or other tissue. They are channels, or pathways that connect together allowing drainage of the veins that are in the brain. In other words, they function to help the collection and return flow of venous blood and cerebrospinal fluid drainage from the tissues and veins in the cerebrum. In Layer 4, we can see the falx cerebri. It is an infolding of the dura mater and separates the cerebral hemispheres. Now moving to Layer 10 in the brain folder, we can observe the cerebral cortex and all the structures inferior to it.
The outer surface of the cerebrum is the cerebral cortex. It is composed of gray matter and just inferior to it is the white mater. We also can see the corpus callosum, which is a large bundle of axons that connect the right cerebral hemisphere to the left cerebral hemisphere. These axons carry information, in the form of nerve impulses, from one hemisphere to the other. The lateral ventricles are superior to the diencephalon, but are inferior to the corpus callosum. In Layer 3, we can see the basal ganglia. The basal ganglia form a set of interconnected nuclei in the forebrain. They receive a large amount of input from cerebral cortex and after processing it, send it back to the cerebral cortex via thalamus. The different components of the basal ganglia are the caudate nucleus, the putamen and the globus pallidus. The caudate nucleus is the most superior part. It is superior and lateral when compared to the thalamus. The most lateral part of the basal ganglia is the putamen and the most medial part is the globus pallidus. The limbic system is a complex set of brain structures that lie on both sides of the thalamus. It includes structures from the telencephalon, diencephalon, and mesencephalon.
It includes the olfactory bulbs, hippocampus, and amygdala to name a few. This system supports many functions that include emotion, behavior, motivation, long-term memory, and olfaction. It is responsible for emotional life and has do with the formation of memories. The limbic system surrounds that structures that make up the diencephalon and is posterior to the temporal lobe. From the cerebrum view in Layer 5, we can locate the insula, or hidden lobe. It is posterior to the lateral sulcus. In other words, it is hidden beneath the lateral sulcus. In Layer 3, we can see the sulci and gyri. The longitudinal fissure is what separates the left and right hemispheres. The central sulcus separates the parietal lobe from the frontal lobe. It lies in between the precentral gyri (forms the motor strip) and postcentral (forms the primary sensory cortex) gyri. The lateral sulcus, also called the Sylvian fissure, is the most lateral boundary. It separates both the frontal lobe and parietal lobe, which are above, from the temporal lobe, which is below.
In conclusion, we “dissected” the brain from the most superficial layer to the deepest layer and from the most superior layer to the most inferior layer. We were able to do so by using Primal Pictures. Being able to look at each structure from every angle and different layers is very beneficial when first learning about them. This site gives very detailed representations of the structures and explanations of how each structure works, not only on its own, but as a whole. All the structures in the central nervous system that we observed are in some way related and allow for communication to take place, as well as allowing the central nervous system to function as it is supposed to.