Brain stem- tracts and nuclei Flashcards
What separates the crura from the tegmentum?
Substansia nigrae
What does the substansia nigra consist of?
Pars compacta (medially), pars reticulata (laterally)
What does pars compacta produce?
Dopamine
What does pars reticulata produce?
GABA
Where is the oculomotor nucleus located?
Adjacent to periaqueductal grey matter
What is role of pretectal nuclei?
plays key role in pupillary light reflex
Where is trochlear nerve nucleus located?
Anterior to periaqueductal grey matter in lower midbrain
What is the key recognisable feature in the lower midbrain?
The dentato-rubro-thalamo-cortical pathway
What is the anterior convexity of the pons caused by?
The decussation of corticopontine fibres
Where are the nuclei of the facial and abducent nerve located?
The pons
What are the abducent and oculomotor nuclei controlled by?
Pattern generator cells
Where do the medial and lateral vestibulospinal tracts originate?
Vestibular nucleus in the pons and upper medulla
What lies at the level of the pontomedullary junction?
The nuclei associated with vestibulocochlear and glossopharyngeal nerves
What is the function of the medial longitudinal fasciculus?
To execute head turning movements in response to saccadic, optokinetic and vestibulo-ocular reflexes
What is located in the anterior wall of the fourth ventricle?
The hypoglossal, dorsal vagal and vestibular nuclei
Where do the corticospinal tracts decussate?
The lower medulla
Where does the corticospinal pathway descend from?
The posterior limb of the internal capsule
Where do the corticospinal fibres pass through?
Middle three fifths of crus
Where do the frontopontine fibres occupy?
Medial fifth of each crus
Where do temporopontine fibres occupy?
Lateral fifth of each crus
What are frontopontine involved in?
Part of extrapyramidal pathway and control functions such as movement of eyes
Where do the temperopontine fibres terminate?
The cerebellum
What fibres run through the tegmentum?
Medial, spinal and trigeminal lemnisci
What gives the red nucleus its colour?
Its store of iron
Where do fibres from the ventral cochlear nuclei decussate?
The trapezoid body
What is function of vestibular nuclei?
Receive input from the semicircular canals and link with vestibulocerebellum to control posture
What is function of lateral vestibulospinal tract?
Contracts extensor muscles of legs thereby maintaining core balance
Where is nucleus ambiguus located?
Upper medulla
Where do corticospinal tracts decussate?
In the lower medulla
What does the respiratory centre consist of?
2 nuclei in pons and 2 nuclei in medulla
