9.3 Brainstem Flashcards Preview

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Flashcards in 9.3 Brainstem Deck (38)

What are the 4 cranial nerves above the pons?

1, 2, 3, 4


What are the 4 canial nerves attaching to the pons?

5, 6, 7, 8


What are the 4 cranial nerves attaching to the medulla?

9, 10, 11, 12


What are the 4 medial structures of the brainstem?

Coticospinal tract, medial lemniscus, medial longitudinal fasiculus, motor nucleus (3, 4, 6, 12)


What are the 4 lateral structures of the brainstem?

Spinocerebellar tract, spinothalamic, sensory nucleus (5) and sympathetic pathway


Where does swallowing, vomiting, ocughing and sneezing get generated and how

In the medulla by the pre motor nuclei innervating CN IX and X


Where does chewing get generated and how?

In the pons by the supratrigeminal premotor nucleus


Where does conjugate eye movements get generated and how?

Mid brain: by the pre motor nuclei innervating III, IV and VI


Where does the locomotor pattern generator occur and how?

In the pons/midbrain: by the pedunco-pontine nucleus and part of the locus coeruleus with input into the reticulospinal tract


Where does information about the internal environment get mapped onto?

The solitary nucleus - gets information from 9 and 10


Where do pain pathways map onto?

The thalamus, reticular formation, superior colliculus and periaqueductal grey matter


Where are the CV and Resp control centres?

Dorsolateral medulla (open medulla)


What supplies the pone?

paramedian, short circumferential and long circumferential branches of the basilar artery


What would a lesion in the basilar artery cause?

Locked in syndrome


What is the general arrangement of inputs to the brainstem?

Motor = medial, sensory = lateral, visceral = intermediate


Where is the pyramidal decussation and what occurs here and what will you be able to see?

Where the brainstem (medulla) and the spinal cord meet - corticospinal tracts will cross here
You will be able to see the fasiculus gracilis and cuneatus as well as the nucleus gracilis, you can also see the spinal trigneminal nucleus


What occurs at the sensory decussation and what can you see?

Fibres from the DC system will be crossing (nucleus gracilis and cuneatus) to form the medial lemniscus via the internal arcuate fibres
This is where you will start to see the inferior olivary nucleus


Why is it termed the open medulla?

The DC fibres have crossed leaving the central canal open dorsally as the 4th ventricle


What will you no longer see at the open medulla?

The nucleus gracilis and cuneatus as there fibres have cossed to form the medial lemniscus already


What is the new feature you will see at the open medulla?

The fourth ventricle and the inerior cerebellar peduncles


Where do fibres from the inferior cerbellar peduncles go from and to?

Fibres from the dorsal cerebellar and cuneo-cerebellar tracts and from the inferior olivary nucleus to the cerebellum


What occurs at the level of the pons?

The pontine fibres which have their cell bodies in the pontine nuclei cross the midline and enter the C/L cerebellum through the middle cerebellar peduncle


What will you see ventrally at the level of the inferior colliculus?

Substantia nigra and cerebral peduncles


What is the main feature at the level of the inferior colliculus?

Crossing of the superior cerebellar peduncles


What can you see in the interpeduncular fossa at the level of the infecior colliculus?



What are the new features in the midbrain at the level of he inferior colliculus?

substantia nigra, cerebral aqueduct and cerebral peduncles


What is the superior colliculus involved in?

visual reflexes, including a map of visual and somatosensory space


What is the new feature at the superior colliculus?

Red nucleus which is the fibres from the crossing of the superior cerebellar peduncles


What separates the cerebral peduncles and what are the composed of?

The interpeduncular fossa
Composed of all descending tracts that originate in the cerebral corex


What is the function of the reticular formation?

Resp/CV control
Control of gate
Autonomic functioning


What happens to the NTs in the reticular formation?

They diffuse away from the site to have a greater range of action


What are the 3 regions of the reticular formation and what is their role?

Median/Raphe: source of serotenergic system
Paramedian: magnocellular and gigantocellular (efferent) - origin of reticulospinal
Lateral: Parvocellular (efferent) - sensory inputs


what is the role of the seratonergic system?

regulating mood and appetite (think SSRI = depression)


What is the role of the dopaminergic system and where do the cells originate from?

Initiation of movements, reward system
Originate from: Substantia nigra and ventral tegmental nucleus


What is the role of the noradrenergic system and where do the cells originate from?

Regulate attention, arousal and the sleep/wake cycle
Originate from locus coerelus


Where do cholinergic cells originate from?

Septal and basal forebrain nuclei and the pontomesencephalotegmental complex


What is the function of teh solitary nucleus and tract?

integrate and map sensory information from the internal environment and co-ordinate autonomic output to the brain stem and spinal cord


What are the inputs into the solitary nucleus?

VII, IX and X (carrying info from chemoreceptors)