The Pons and Cerebellum

The Pons The pons is a section of the brain stem that lies between the midbrain and the medulla oblongata Visually it looks like an enlarged section of the medulla oblongata It’s the “butt” of the brain stem However the actual structure of the pons and its function are quite different

The Pons The cerebellum lies dorsal to the pons The pons links the cerebellum with the midbrain, diencephalon, cerebrum, medulla and spinal cord

The Pons The pons serves as the gateway between sections of the brain It also has several other important functions These include sensory visceral and somatic organ control, motor visceral and somatic organ control and coordination of signals during sleep The pons is directly responsible for the stage of sleep called REM sleep

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Components of the Pons The pons contains four different types of components 1) Sensory and motor nuclei of control nerves These enervate the jaw, the anterior surface of the face, one of the eye muscles and sense organs of the internal ear

Components of the Pons 2) Nuclei involved with the control of respiration On each side of the pons, the reticular formation continues from the medulla The section in the pons has control centers that help the section of the medulla that controls respiration

Components of the Pons 3) Nuclei and tracts that process and relay information sent to or from the cerebellum This is the section of the pons that we talked about earlier It links the pons to the brain stem, cerebrum and spinal cord This is how it relays information to higher sections of the brain

Components of the Pons 4) Ascending, descending and transverse tracts These are sections of nerves that connect the pons to the cerebellum These nerves connect the nuclei of the pons to the cerebellar nerves

The Cerebellum The cerebellum is the autonomic processing center of the brain It is also the site of processing for voluntary movement This means it coordinates activities such as staying balanced with activities such as running

The Cerebellum The cerebellum is the most identifiable part of the brain due to its highly folded structure Folia are complex folds that cover the cerebellum surface These are used to create a higher surface area and allow for a larger number of nerves in the cerebellum

The Cerebellum The cerebellum is divided into two lobes, the anterior and the posterior lobes These lobes are identified by their position in the cerebellum The lobes are separated by the primary fissure

The Cerebellum The cerebellum is also divided into two separate hemispheres These hemispheres are termed the right hemisphere of the cerebellum and the left hemisphere of the cerebellum They are divided by a ridge called the vermis

The Cerebellum The cerebellum has a large number of specific nerve cells These Purkinje cells have extensive dendrites that can connect to up to 200,000 synapses This means that they can coordinate large amounts of information very quickly

Jobs of the Cerebellum The cerebellum coordinates functions of balance and fine muscle control Generally these jobs work together A good example would be a person that has to jump to catch a fly ball They have to be able to use fine motor control to be able to catch the ball and their balance to land safely

Jobs of the Cerebellum To do this the cerebellum must communicate between the spinal cord and the higher levels of the brain to cause somatic, visceral and higher level changes The information that is sent to the cerebellum is often coordinated or routed through the pons before it makes it to the Purkinje cells

Jobs of the Cerebellum It is possible for someone to damage their cerebellum A damaged cerebellum happens most often when there is trauma to the back of the head, from blood loss or from interference by drugs People who are drunk tend to have trouble coordinating their motor control This is because alcohol blocks messages being sent it the cerebellum

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Jobs of the Cerebellum Ataxia is the result when the cerebellum is not functioning correctly It can be temporary (in the case of alcohol) or permanent (in the case of a stroke) Ataxia levels can range from having alight abilities to balance and loss of fine motor control Severe ataxia can cause the inability to balance and use any motor control

Video https://www.youtube.com/watc h?v=mrt0Gq0zS4g Cerebellum Dissection