Brain Stem Flashcards
Describe the composition of the Midbrain
Cerebral peduncles and tectum
What comprises the cerebral peduncles
Comprises of the Tegmetum, substantia nigra and the crus cerebri
What runs in the crus cerebri
Motor tracts of the corticospinal tract
Which level are the red nuclei and its function
In the Midbrain and through the rubralspinal tract will regulate flexion in the upper limbs
What features define the Midbrain
Intrapeduncular fossa, has the red nuclei, has the cerebral aquaduct from the third ventricle to the 4th, also has the periaquaductal gray matter that regulate pain control
What are the roles of the superior and inferior colliculi
Inferior = Auditory ascending fibres which are then projected to the medial geniculate nucleus of the thalamus
Superior = Receives inout from the retina and can control saccadic eye movement (fast)
Define particular regions of the pons
The pons consists of the 4th ventricle, The pontine nuclei (ventral) and pontine reticular formation. Also will have the basil regions in which the tracts will pass through
Define the particular shape of the Medualla
Has a butterfly shape and begins to look like a butterfly
What are the differences between rostral and caudal medulla
The rostral is larger in size while the caudal is smaller. Both have the olivary nuclei and the medulla pyramids while the rostral has just the superior olive. The superior olive is involved in the hearing pathway while the inferior olive is involved in the cerebellar pathways
Exits of the CNs from Brain Stem
4 above the pons = CN III (below the mamillary bodies), IV very lateral at the most caudal region of the midbrain
4 at the pons = 5 is the largest in the lateral, 6 is medial on the pons while 7 and 8 exit together in the lateral region
4 below the pons = CN9 and 10 will exit lateral, CN XII will exit medially will CNXI will ascend from the spinal cord and exit laterally.
What is the funciton of the Reticular formation
- Modulation of sensation such as Pain
- Control of posture and balance via axial muscles in the reticulo-spinal tracts
- Controls of
- Heart rate
- Breathing rate
- Blood pressure
- Swallowing
- Vomiting
Arousal via the ascending reticular activating system
At what level is the 4th ventricle
The Dorsal aspect of the Pons
What does the tectum comprise?
The inferior and superior colliculi
What does the Tegmentum comprise
The CN nuclei and the reticular formation
What does the basilar region comprise
The White matter tracts that are ascending and descending
