Taking up the inferior and posterior aspect of the cranial cavity, the cerebellum is the second largest structure attributed to the brain. Positioned within the metencephalon, it is segregated via the transverse fissure from the overlying cerebrum. The transverse fissure accepts a segment of the meninges known as the tentorium cerebelli.


The cerebellum is created by two hemispheres and one area of central constriction known as the vermis. Protruding between the hemispheres is the falx cerebelli, which is part of the meninges. The outer layer of the cerebellum is like that of the cerebrum, a slight layer of gray matter. This gray matter layer is known as the cerebellar cortex. The white matter beneath this outer layer is much thicker. Parallel and slight folia is created by the convolutions of the gray matter of the cerebellum. When looking at the brain from a saggital viewpoint, the arbor vitae can be clearly distinguished, looking like a network of white thin matter branching off in all directions. The nerve bundles, which are created by three equally paired groups of nerves, in known as the cerebellum peduncle. The peduncle is a supportive structure that assists in laying the groundwork for the cerebellum’s communication with the rest of the brain.

Connecting the cerebellum with the midbrain is the superior peduncle. The nerves of the bundle, or more specifically the fibers of the bundle, begin their existence from the specialized dentate nuclei that is housed by the cerebellum. Passing through the red nucleus to the thalamus and then continuing on to the motor areas of the cerebral cortex, the cerebrum is then able to receive the appropriate feedback and communications via impulses.


Image: Cerebellum

Voluntary movement impulses are sent via middle cerebellar peduncles, originating in the cerebrum and traveling through the pons and on to the cerebellum.


Inferior cerebellar peduncles are responsible for adjoining the cerebellum with the medulla oblongata as well as the spinal cord. Equipped with incoming vestibular fibers and proprioceptive fibers, as well as outgoing motor fibers, the basic responsibility of the inferior cerebellar peduncles is to transmit the information necessary to obtain coordinated skeletal muscular contraction, which created body movement.

Voluntary skeletal muscle movement impulses begin in the cerebral cortex and are them transmitted in coordinated efforts by the cerebellum. The cerebellum is really quite busy continuously transmitting impulses to specific motor units in order to maintain muscular tone and posture. The proprioceptors send the cerebellum impulses for interpretation from the muscles, joints, tendons, and special sense organs as these improve learned fine motor development. A proprioceptor is a specialized sensory nerve ending designed to be susceptible to variations in muscular or tendon tone and tightness.
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