Neuro exam 3 class 2

The brainstem and cerebellum are a part of the brain and therefore are apart of the

Central nervous system

The brainstem is composed of 3 parts (from superior to inferior

Midbrain, pons, medulla oblongata

the inferior portion of the brainstem, the medulla, is

continuous nervous tissue with the spinal cord

what designates where the brain and spinal cord begin

foramen magnum

what is the most inferior and posterior of the brain parts

cerebellum

1. vertical tract runs through the brainstem

sensory, autonomic, and motor tracts travel through the brain stem, just as in the spinal cord

brainstem acts as a conduit for the continuing tracts, and some tracts originate in

the brain stem region

10 out of 12 pairs of cranial nerves originate on the

brainstem

2. Longitudinal sections

Basilar, tegmentum, tectum

basilar: anterior located, contains

predominantly motor structures although some sensory

tegmentum: posteriorly located to basilar contains

sensory nuclei/tracts, reticular formation and cranial nerve nuclei, involved in adjusting general level neural activity

tectum: posterior to tegmentum in midbrain, regulates

eye and auditory reflexes and reflexive head movements.

3. Reticular formation of the tegmentum

complex neural network formation within the tegmentum, including the reticular nuclei, their connections and ascending and descending reticular pathways

reticular formation can be divided into 3 longitudinal zones

lateral zone, Medial zone, midline zone

lateral zone:

integrates sensory and cortical input

medial zone:

regulates vital functions, somatic motor activity and attention

midline zone:

adjusts transmission of pain info, somatic motor activity, and consciousness levels

reticular nuclei

it regulates the passage of ascending/descending information by releasing chemical signals (neurotransmitters)

ventral tegmental area/nucleus (lateral zone)

dopamine (motor control/ coordination, behavior)

pedunculopontine Nucleus (lateral zone):

acetylcholine (arousal, ascending signals to thalamus and cerebrum)

locus ceruleus/ cerulean nucleus (lateral zone):

norepinephrine (enhanced movement percision, increase wakefulness)

medial reticular zone:

epinephrine/ norepinephrine (movement control)

Raphe Nuclei (midline zone):

serotonin (pain inhibition, mood regulation, anxiety reduction, consciousness)

Medulla

control of eye and head movements, coordinates swallowing, and helps regulate cardiovascular, respiratory and other visceral activity

pyramids:

anteriorly, the medulla has tv vertical ridges called pyramids. most corticospinal axons cross the midli in the pyramid decussation

pons

process motor information from the cerebral cortx and forwards it to cerebellum

midbrain

relay station for visual and auditory information, controls body movements

anatomy of cerebellum: cortex

outer cortical region- gray matter consisting of three cortical layers

three cortical layers:

outer layer/ molecular layer: Purkinje cells dendrites

middle layer/Purkinje cell layer: Purkinje cell bodies

inner layer/granular layer: granule cells and golgi cells

cortex 2 inner cortical region

whote matter- deeply seated within the cortex consists of cerebellar nuclei, recieves input from purkinje cells

lobes of the cerebellum (divides cerebellum from rostral to caudal direction)

1. anterior: most superior lobe, separated from posterior lobe by primary fissure

2. posterior: most inferior, largest lobe

3. flocculondular: tucked underneath the posterior lobe, touching the brainstem

three specialized regions of cerebellum coordinate body movements and postural control:

vestibulocerebellum, spinocerebellum, cerebrocerebellum

vestibulocerebellum (flocculonodular lobe):

balance and spatial orientation

spinocerebellum (vermal and paravermal)

vermal hemisphere: processes auditory and vestibular information and posture

Paravermal hemisphere: gross limb movements

cerebrocerebellum (lateral hemispheres)

controls distal, fine and coluntary movements

brainstem disorders

dysphagia, dysarthria, diplopia, dysmetria

dysphagia

difficulty swallowing: affecting pharynx, gag reflex cranial nerve

dysarthria

difficulty in speaking: speech disorder can cause slurred or abnormal articulation; affects the ability to form words

diplopia:

eye movement disorders causing double images: cranial nerves originate on the brainstem and deal with eye movements via ocular muscles

dysmetria

inability to determine distance of movements: affects reaching for objects or stepping: over or underestimating where an object is located

cerebellum disorders:

ataxia, dysarthria, dysmetria

ataxia:

imbalance and loss of coordination of movement: failure of muscle control: can result in stumbling, balance issues , slurred speech, balance issues

c. dysarthria

motor problems with speech: neurological damage that cause speech disorder c

c. dysmetria:

to determine distance of movements: affects reaching for objects c