The Brainstem Flashcards
What are the three major fibre tracts of the spinal cord?
Ascending
- Dorsal column - medial lemnicus system (touch)
- Anterolateral system (pain)
Descending
- Corticospinal tract
Apart from the face, what else do certain cranial nerve supply?
CN9,10 and 11 also supply visceral, sensory and motor innervation to neck, chest and most of abdominal organs
Which CNs exit from the medulla?
9-12
Where does decussation occur in the anterolateral system (pain)?
In the spinal cord
Are cranial nerve nuclei located in the tectum or tegmentum?
Tegmentum
Ancephalic babies, if born, are able to do what?
Swallow, cry, breathe and suckle
How is the tegmentum located in relation to the rest of the CNS?
It is the central pathway of the brainstem which is continuous with the spinal cord - everything coming or going to PNS goes through it
Where does decussation occur in the corticospinal tract?
Pyramidal decussation
Where does decussation occur in the dorsal column tract (touch)
Medial lemniscus of the medulla
What are 3 parts of the brainstem in decending order?
Midbrain
Pons
Medulla oblongata
What is the function of the caudal reticular formation?
Crucial functions in motor reflexes and automonic functions
eg vomiting
What embryological feature do the sensory nuclei develop from?
The alar plate
What are the general functions of the brainstem?
Reflexive and unconscious behaviour
Modulation of various arousal and conscious states
Are the CN motor nuclei located closer or further from the midline cf. to the sensory nuclei?
Motor are closer
Sensory are more lateral
How many colliculi are there on the midbrain?
4
Where in the brainstem is the reticular formation located?
At all level - also extends rostrally into the thalamus and caudally into the grey matter of the spinal cord
What is on the dorsal aspect of the medulla?
Dorsal columns and nuclei
What embryological feature do the motor nuclei develop from?
The basal plate
Which cranial nerves are a mixture of motor and sensory?
5,7,9,10
Where are the cerebral peduncles found?
Ventral aspect of the midbrain
Is the recticular formation on the dorsal or ventral aspect?
Dorsal
Which cranial nerves exit from the midbrain?
3,4
Where do the cranial nerve nuclei lie during development?
Next to the ventricles
What is on the ventral aspect of the midbrain?
Cerebral peduncles - motor tract from the motor cortex
What is the tectum?
The roof of the midbrain - located superiodorsal
T/F the colliculi of the midbrain are located in the tegmentum?
False, they’re in the tectum
In general, in the brainstem the ventral aspect contains … while the dorsal aspest contains …
Motor control tracts
Cranial nerves
The basis of the brainstem is important for what?
Descending motor control
What the features of the posterior aspect of the pons?
4th ventricle lies on top
Facial colliculi formed by the abducens nucleus and CN7
Which CNs exit from the pons?
5-8
Which cranial nerves exit from above the midbrain
1,2
What is the function of the midbrain colliculi?
Eye movement control
Hearing
Where in the cranium is the braistem located?
In the posterior cranial fossa
Where is the pyramidal decussation found?
At the base of the medulla
What are the bumps on the posterior aspect of the midbrain called?
Colliculi (meaing hills)
