brainstem and cranial nerves I Flashcards
where is the brainstem located?
between the forebrain and spinal cord
what foes the forebrain divide into?
telencephalon
diencephalon
what makes up the brainstem?
midbrain
pons
medulla
what is the oldest part of the brain evolutionarily?
brainstem
what are the functions of the midbrain?
processes visual, auditory data.
Maintains consciousness
Also reflexive somatic motor responses bc of the colliculi on top of the midbrain)
what are the functions of the pons?
relays sensory information to cerebellum and thalamus. Subconscious somatic and visceral motor centres
what are the functions of the medulla?
relays sensory information to thalamus. Contains autonomic centres for regulation of visceral function
name the main functions of the brainstem?
conduit - long tracts to or from spinal cord pass through brainstem
cranial nerve function - sensory input/motor output for the head plus parasympathetic motor output. Cranial nerves carry special senses, brainstem coordinates reflexes involving them
integration centres - relays info to cerebellum
reticular formation - interconnected nuclei throughout brainstem
what do the nuclei of reticular formation mediate?
o Autonomic control of important respiratory/cardiovascular reflexes and other behaviours e.g. swallowing, sneezing
o Somatic/autonomic modulation via descending pathways
o Important in regulation of consciousness.
what is the brainstem?
an extension and elaboration of the spinal cord
at what spinal level does the spinal cord become the brainstem?
C2
what happens to sensory and motor nuclei when they move from the spinal cord to the brainstem?
Sensory nuclei that were dorsal in the spinal cord move laterally, motor nuclei move medially
what is found in the dorsal part of the brainstem?
cranial nerve nuclei found here and sensory reflex centres
what is the name for the dorsal part of the brainstem?
tectum
what is the name for the middle part of the brainstem?
tegmentum
what does the tegmentum contain?
ascending pathways and reticular formation
what does the ventral part of the brainstem contain?
descending motor pathways e.g. corticospinal and corticobulbar tracts
where are the superior and inferior colliculus found?
in the midbrain
where is the cerebral peduncle found?
in the midbrain
what does the cerebral peduncles contain?
tracts descending from the cortex through the brainstem to the spinal cord (corticospinal).
what are the functions of the different regions of the pons?
- Superior: main output path from the cerebellum to the midbrain.
- Middle: afferent input from pontine nucleus (motor activity).
- 4th ventricle (found medially).
- Basal pons: bridge composed of transverse and descending fibres