Brainstem Nuclei and Tracts Flashcards
where is brainstem located
between cerebrum and spinal cord
what does the brainstem consist of
midbrain, medulla and pons
what is brainstem made of
deep grey matter surrounded by white matter tracts
which pathway of the spinal cord is ascending
sensory
what pathway of the spinal cord is decending
motor
what does the midbrain develop from
mesencephalon
what does the pons develop from
rhombencephalon
what does the medulla oblongata develop from
rhombencephalon
what does the spinal cord develop from
rhombencephalon
what is the corticobulbar tract
a motor pathway that goes from the cortex to the brainstem
what are the corticospinal tracts
motor pathways that travel along the spinal cord
what does the lateral corticospinal tract do
conveys commands to the body (piano playing, tap dancing)
what does the anterior corticospinal tract do
controls trunk muscles (core exercises)
what is the optic chiasm
where optic nerves cross over
what is the middle ceerebellar peduncle
connects pons to cerebellum
what does the superior colliculis relate to
vision
what does the inferior colliculus refer to
hearing
which cranial nerves do not originate from the brain stem
I & II
where does the occulomotor nerve (III) emerge from
interpenduncular fossa
where does the trochlear nerve (IV) emerge from
posterior aspect of brainstem
where does the trigeminal nerve (V) emerge from
anterolateral section of pons
where does the abducens nerve (VI) emerge from
pontomedullary junction
what is the pontomedullary juntion
part of pons where it meets medulla oblongata
where does the facial nerve (VII) emerge from
pontomedullary junction
where does the vestibulocochlear nerve (XIII) emerge from
pontomedullary junction
where does the glossopharyngeal nerve (IX) emerge from
medulla oblongata
where does the vagus nerve (X) emerge from
medulla oblongata
where does the spinal accessory nerve (XI) emerge from
medulla oblongata
where foes the hypoglossal nerve (XII) emerge from
medulla oblongata
what does the ventral part of the midbrain relate to
motor
what does the dorsal aspect of the midbrain relate to
sensory
what separates the ventral and dorsal aspects of the midbrain
cerebral aqueduct
what do the superior colliculi and inferior colliculi make up together
corpora quadrigemina
what do the superior colliculi do
relay input from the optic tract to the lateral geniculate bodies of the thalamus
what do the inferior colliculi do
send information to the medial geniculate bodies of the thalamus
what is the reticular activating system
present throughout the brainstem and it is involved in sleep wake cycles
three nuclei types of the midbrain
- red nuclei
- nuclei of cranial nerves III & IV
- substantia nigra
what are the red nuclei
- contain numerous blood vessels
- receive information from cerebellum and cerebrum
- issues subconscious motor commands concerned with muscle tone and posture
what is the substantia nigra
- lateral to the red nucleus
- contains melanin
- seceretes dopamine to inhibit the excitatory neurons of the basal nuclei
what happens when there is degeneration of the substantia nigra
parkinsons
what do the motor tracts of the midbrain do
- includes fibres of pyramidal system
- pass downward on midbrain’s ventral surface
what do sensory axons in midbrain do
- include those from spinothalamic tract
- ascend along dorsal midbrain
what are the cerebral peduncles also called
crus cerebri
what are the cerebral peduncles
efferent projections including corticobulbar and corticospinal axons
what four cranial nerve nuclei are found in the pons
- trigeminal (V)
- abducens (VI)
- facial (VII)
- vestibulocochlear (VIII)
nuclei of pons
not cranial nerves
- apneustic and pneumotaxic centres work with medulla to maintain respiratory rhythm
- raphe nuclei
- reticular activating system
tracts of the pons
- superior, middle and inferior cerebellar peduncles
- motor and sensory tracts (sensory fibres are always posterior to motor fibres)
what are the cerebellar peduncles
tracts that process and relay information to and from the cerebellum
what are the nuclei of the medulla associated with
- autonomic control
- cranial nerves
- sensory/motor relays
three types of nuclei present in medulla
- autonomic nuclei
- sensory and motor of 5 cranial nerves
- relay nuclei
three types of autonomic nuclei
medulla
- cardiovascular centres
- respiratory rhythmicity centres
- additional centres
what do cardiovascular centres do
- alter rate and force of contractions
- alter tone of vascular smooth muscle
what do respiratory rhythmicity centres do
recieve input from pons to control respiratory rhythm
additional centre examples
medulla autonimic nuclei
- emesis
- deglutition
- coughing
- hiccupping
- sneezing
what four cranial nerves have their nuclei in the medulla
- glossopharyngeal (IX)
- vagus (X)
- spinal accessory (XI)
- hypoglossal (XII)
what are the relay nuclei
- nucleaus gracilis and nucleus cuneatas pass somatic sensory information to thalamus
- olivary nuclei relay information from spinal cord, cerebral cortex and brainstem to cerebellar cortx
what tracts are present in the medulla
ventrally, 2 ridges (medullary pyramids) are visible
these are formed by the large motor corticospinal tracts
