Cerebellum

Try to answer with Multiple choice muna then Identification.

Posterior Cranial Fossa, Posterior to the 4th Ventricle, the Pons and the Medulla Oblangata

Location of the Cerebellum

Tentorium Cerebelli

What separates the Cerebellum from the Cerebral Cortex?

Vermis

What separates the 2 Cerebellar hemispheres?

Fine Control and Coordination of simple and complex movements

General function of the Cerebellum

Coordinating posture, Balance in walking and running, Executing sequential movement in eating, dressing and writing, Producing rapidly alternating repetitive movements, Smooth pursuit movements, Controlling certain properties of movement including velocity and acceleration.

Give atleast 3 applications of the function of the cerebellum.

Vestibular nerve : Tectocerebellar Tract

Where does the Cerebellum receive information for balance and sight? (1 : 2 format)

Anterior Lobe

• Involved with the control of muscle tone

• Paleocerebellum

• Seen on the superior surface of the cerebellum

• Separated from the Middle lobe by the Primary Fissure

Paleocerebellum

Other name for the Cerebellum which means the 2nd oldest part.

Middle/Posterior Lobe

• Concerned with Coordination and Voluntary Motor function

• Largest part of the Cerebellum

• Receives input from the Cerebral Hemisphere via the Middle Cerebellar Peduncle

• Situated between the Primary fissure and the Uvolonodular Fissure

Neocerebellum

Other name for the Middle / Posterior lobe which means the newest lobe

Flocculonodular lobe

• Composed of a pair of Floccules

• Inferior to the Vermis.

• Posterior to the Uvolonodular fissure

• Related primarily to the vestibular system (Balance)

Archicerebellum

Other name for the Flocculonodular lobe which means oldest part of the cerebellum

Primary Fissure

Wide V-shaped fissure that separates the Anterior lobe from the Middle/Posterior lobe.

Uvolonodular fissure

* Located on the inferior surface within the Middle lobe, separates the Middle lobe from the Flocculonodular lobe.

Intercerebral Nuclei

The cerebellum is composed of a gray matter outer layer and an inner white layer, in that white layer are 3 masses of gray matter, what is that structure called?

Cerebellar Cortex

This can be regarded as a large sheet with folds lying in the Coronal or Transverse plane

Folium

Cerebellar folds

Molecular / External layer

Layer of the Cerebellum that has 2 types of neurons, Stellate (outer) and Basket (inner) cells. This layer also has neuroglial cells between the structures.

Purkinje / Middle layer

This layer of the cerebellum has Purkinje cells arranged in a single layer.

Purkinje Cells

Golgi type 1 neurons that are flask - shaped and is the functional unit of the cerebellar cortex.

Granular / Internal layer

This layer of the cerebellum is packed densely with small cells that give rise to 4 to 5 dendrites which make claw-like endings.

Cortex of the Vermis, Intermediate Zone and the Lateral Zone

The functional areas of the Cerebellar cortex.

Cortex of the Vermis

Area of the cerebellum that influences the movements of the body specifically the neck, shoulders, thorax, abdomen and hips.

Intermediate Zone

This area of the cerebellum is immediately lateral to the vermis, it controls the muscles of the DISTAL parts of the limbs

Lateral Zone

This area of the cerebellum is concerned with the planning of sequential movements of the body.

Dentate Nucleus

• Largest cerebellar nuclei

• Shape: Crumpled bag with an opening facing medially

• Inferior of the bag is filled with white matter made up of Efferent fibers that leave the nucleus through the opening to form a large part of the Superior Cerebellar Peduncle.

Emboliform Nucleus

Situated medial to the dentate nucleus

Globose Nucleus

Consists of one or more rounded cell group that lie medial to the emboliform nucleus.

Fastigial Nucleus

Lies near the midline in the vermis and close to the roof of the 4th ventricle.

Superior Cerebellar Peduncle

• Composed mostly of efferent projection from the Cerebellum

• Composed of afferent projection from the VENTRAL SPINOTHALAMIC TRACT

Brachium Conjunctivum

Other name for the Superior Cerebellar Peduncle

Middle Cerebellar Peduncle

* Mostly composed of crossed afferent fibers from the contralateral pontine nuclei in the gray substance of the basal pons

Brachium Pontis

Other name for the Middle Cerebellar Peduncle

Inferior Cerebellar Peduncle

• Composed mostly of afferent fibers, and a single efferent pathway called the Fastigiobulbar tract (Juxtarestiform body)

• Sources of Entry to the Cerebellum

Restiform body

Other name for the Inferior Cerebellar Peduncle

Vestibular Nerve and Nuclei, Inferior Olivary Nuclei, Dorsal Spinocerebellar Tract, Some Rostral Spinocerebellar tract, Cuneocerebellar tract from the Accessory Nuclei in the Medulla, Reticulocerebellar Tract.

Sources of Entry to the Cerebellum

Arbor Vitae

Structure of the white matter that resembles a tree’s branches found in the vermis

Intrinsic White Matter

• Don’t leave the cerebellum but connect the different regions of the organ.

• Some fibers interconnect the folia and vermis on the same side.

Afferent White Matter

• Greater part of the white matter

• Proceeds to the cerebellar cortex

• Enter the cerebellum via the Inferior and Middle Cerebellar Peduncles

Efferent White Matter

• Constitute the output of the cerebellum and begin as the axons of the Purkinje cells of the cortex

• The great majority of the Purkinje cells axon pass to and synapse with the neurons of the cerebellar nuclei (Fastigial, Globose, Emboliform, Dentate) and leave through

  • Dentate, Emboliform, Globose : Superior Peduncle

  • Fastigial: Inferior Peduncle

Anterior Spinocerebellar Tract

• Most of the axon cross to the opposite side and ascend as anterior spinocerebellar tract in the contralateral white column

• Some of the axon ascend as anterior spinocerebellar tract in the lateral white column of the same side

• The fibers ENTER the cerebellum through the superior cerebellar peduncle and TERMINATES in the cerebellar cortex

• Function: Info from muscle and joints

Posterior Spinocerebellar Tract

• The axons enter the posterolateral part of the latera white column on the same side and ascend as the posterior spinocerebellar tract to the medulla oblongata

• The tract ENTERS the cerebellum through the inferior cerebellar peduncle and TERMINATES in the cerebellar cortex

• Function: Info from muscle and joints

Cuneocerebellar Tract

• Function: Conveys information from muscles and joints of Upper Limb

• The fibers ORIGINATE in the Nucleus Cuneatus of the Medulla Oblongata and ENTER the Cerebellar Hemisphere on the same side through the Inferior Cerebellar Peduncle.

Dentatothalamic Pathway

• Origin: Dentate Nucleus

• Destination: C/L ventrolateral nucleus of the thalamus and then to the C/L motor cerebral cortex.

  • Corticospinal tract crosses the midline and controls IPL motor neurons in SC.

• Function: IPL motor activity

  • Travels through the superior cerebellar peduncles

Fastigial Vestibular Pathway

• Origin: Fastigial Nucleus

• Destination: IPL and C/L lateral vestibular nuclei

  • (both lateral vestibular nuclei on either side); vestibulospinal tract to IPL motor neurons in SC.

• Function: IPL extensor muscle tone

  • Travels through inferior cerebellar peduncles

Fastigial Reticular Pathway

• Origin: Fastigial Nucleus

• Destination: Neurons of reticular formation.

  • Reticulospinal tract to IPL motor neurons to the SC.

• Function: IPL muscle tone

  • Travels through the inferior cerebellar peduncles. \n