CEREBRUM

 

The cerebrum is a large part of the brain containing the cerebral cortex (of the two cerebral hemispheres), as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. In humans, the cerebrum is the uppermost region of the central nervous system. The telencephalon is the embryonic structure from which the cerebrum develops prenatally. In mammals, the dorsal telencephalon, or pallium, develops into the cerebral cortex, and the ventral telencephalon, or subpallium, becomes the basal ganglia. The cerebrum is also divided into approximately symmetric left and right cerebral hemispheres.

With the assistance of the cerebellum, the cerebrum controls all voluntary actions in the body.

The cerebrum is the largest part of the brain. Depending upon the position of the animal it lies either in front or on top of the brainstem. In humans, the cerebrum is the largest and best-developed of the five major divisions of the brain. The cerebrum is the newest structure in the phylogenetic sense, and in mammals it is the largest and most developed, out of all known species.

The cerebrum is made up of the two cerebral hemispheres and their cortices, (the outer layers of grey matter), and the underlying regions of white matter. Its subcortical structures include the hippocampus, basal ganglia and olfactory bulb. The cerebrum consists of two cerebral hemispheres, separated from each other by a deep fissure called the longitudinal fissure.

Lobes and Functions

The cerebrum is divided into four regions called lobes that control senses, thoughts, and movements. The four lobes are the occipital, temporal, frontal, and parietal lobes. Although each lobe has a different task to perform, they all must work together.

The occipital lobe, found in the back of your cerebrum, plays a role in processing visual information. It can be related to oculus, the Latin word for eye.

There are two temporal lobes, one in each hemisphere – close to where your ears are. It primarily functions in auditory processing. However, it may also be involved in emotion, learning, and pronunciation/learning a new language. If you hear a loud tempo or beat, you may cover your ears, thus blocking the sounds from getting to your temporal lobe.

The frontal lobe allows you to solve a complex task, undergo voluntary movement of your body parts, form complete sentences, and is responsible for your personality traits. Think about the last time you had a difficult exam, what was your first reaction? You probably put your elbow on the table and your hand on your forehead, precisely where your frontal lobe is located.

The parietal lobe functions in general sensation and feeling. If you stand too close to a campfire, you probably take a few steps backwards to avoid the excessive heat. Building a snowman without gloves may also bring you discomfort, but your parietal lobe helps to communicate this information with the rest of your brain. Although all sensations are not bad, it is important to point out how they help us avoid potentially harmful situations. The parietal lobe is found in between the frontal and occipital lobe.

Parts Within the Lobes

Throughout the cerebrum we find elevated regions called gyri (gyrus for singular). They help to separate the lobes based on its functional roles and increase the overall size of the cerebrum. The specific gyrus used for motor functions in the frontal lobe is called the precentral gyrus; whereas the gyrus used for sensory function in the parietal lobe is called the postcentral gyrus. An example of a motor function may include reaching into your pocket for correct change. A sensory function would be the feeling you get when touching the two coins. Finally, the central sulcus is a deepened groove used to separate the frontal lobe from the parietal lobe.

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