Brain Stem Flashcards
Where is the fourth ventricle located?
Partly in the medulla and partly in the pons.
Where are the corticospinal fibres located in the brain stem?
Pyramid of the medulla
What two fasciculi continue to travel from the spinal cord to the medulla?
Gracile and cuneate fasciculi.
How many cranial nerves are attached to the medulla?
7
Abducens
Facial
Vestibulocochlear
Glossopharyngeal
Vagus
Accessory
Hypoglossal
Which part of the brain stem attaches to the cerebellum?
Pons
The basal pons blends laterally into the middle cerebellar peduncles with the attachment of the trigeminal nerve marking the transition
What is the importance of the basal pons?
Serves as a large synaptic relay station, providing a connection from the cortex of each cerebral hemisphere to the opposite cerebellar hemisphere,
What structure is situated immediately below the cerebral peduncles and inferior colliculi of the midbrain?
Isthmus of the brain stem
What is the purpose of the foramen of Magendie (median aperture of the fourth ventricle)?
A hole that provides the principal communication between the ventricular system and the subarachnoid space
What does the choroid plexus secrete and where is it located?
CSF in the fourth ventricle.
What are the several functions of primary performance of the the reticular formation
- Influence levels of consciousness and degree of alertness
- Control of movement through efferents to the spinal cord and to motor nuclei of cranial nerves
- Contributing to visceral and other involuntary activities through groups of neurons that function as cardiovascular and respiratory centres.
What transitional zones are located in the ventral grey horns of the medulla?
Extend to the region of decussation which includes motor cells for the first cervical nerve and the spinal root for the accessory nerve. From here, it passes from the pyramids to the corticospinal tracts.
What are the dorsal grey horns replaced by?
Spinal trigeminal nuclei
Where does the medial lemniscus system tract end?
The lateral division of the ventral posterior nucleus of the thalamus
What two tracts merge together to form the spinal lemniscus?
Spinothalamic and spinotectal tracts
What are the three routes from the spinal cord to the thalamus and cerebral cortex?
- Medial lemniscus system
- Neospinothalamic system
- Paleospinothalamic system
Where are the dorsal and ventral spinocerebellar tracts located?
Near the lateral surface of the medulla
What does the cuneocerebellar fibres provide?
A pathway to the cerebellum from proprioceptive and other sensory endings in the neck and upper limb
What information is passed through the inferior cerebellum?
Spinal cord to cerebellum
What information is passed through the middle cerebellum peduncle?
Cerebellum to cerebellum via pons
What is the medulla?
Continuation between spinal cord and brain stem
What is the basis pedunculi composed of?
Corticospinal
Corticobulbar
Corticopontine fibres
What information does the superior colliculus pick up?
Vision
What information does the inferior colliculus pick up?
Auditory stimuli
What is the gracile fasciculus concerned with?
Sensations from the leg and lower trunk
Medial
What is the cuneate fasciculus carry?
Sensations from the upper trunk, arm and neck
Lateral
What does the spinothalamic tract pick up?
Pain, temp, touch on opposite sides
What does the spinotectal tract pick up?
Sensory information to the superior colliculus and the reticular formation of the midbrain and then into the medulla
