08 - NS Diencephalon, Brainstem & Cerebellum Flashcards
What are the components of the diencephalon
Hypothalamus:
Posterior pituitary:
Epithalamus:
Thalamus
What does selective attention entail
context, vision, taste, hearing (pain, temp, proprioception, touch/pressure)
Everything but smell!
Hypothalamus function
Hypothalamus:
- endocrine regulation
- automatic system regulation (BP, HR, digestion, respiratory, pupil)
- pleasure, fear, rage
- temp regulation
- appetite and thirst
Posterior pituitary function
- oxytocin (uterine contractions, lactation)
- vasopressin - ADH (water retenation, vasoconstriction
Epithalamus function
- pineal gland (melatonin) - sleep, circadin rhythms, regulated by SCN of hypothalamus
Thalamus function
- relay nuclei for memory, motor and sensations to the cerebral cortex
- Memory & emotions (links mammillary bodies to cingulate cortex)
- Motor (determines balance between basal nuclei and cerebellar output to premotor cortex)
- sensations: vision, touch, pain, hearing, pressure, prosterior
- cortical input (inputs from cerebral cortex determine which sensations can or cannot pass to the cortex - selective attention)
What are the structures of the brain stem
midbrain, pons and medulla
Where do the cranial nerves come from
brainstem
- 4 above pons
- 4 in pons
- 4 below pons
Midbrain
contains axons of precentral gyrus
- cerebral peduncles
- corticospinal motor tracts
Pons
relay nuclei from cortex to cerebellum via cerebellar peduncle pontine respiratory nuclei
- motor info shared with cerebellum
Medulla
pyramidal decussation (corticospinal motor tracts)
- crosses over right side, controls left side vice versa
Where are most of the cranial nerve nuclei found
brainstem
what are the somatosensory tracts
- cuneate fasciculus
- gracile fasciculus
Describe the structures of the midbrain
- tectum (“roof”)
- periaqueductal gray matter (PAG)
- oculomotor nucleus (III)
- medial lemniscus
- red nucleus
- substantia nigra (signals to basal nuclei DA facilitates striatum of basal nuclei)
- fibers of pyramidal tract)
- superior colliculus (visual reflex relay)
- cerebral aqueduct
- reticular formation
- cerebral peduncle
- inferior colliculi (auditory reflex relay)
What happens when dopaminergic neurons of the substantia nigra are reduced
Parkinson’s disease
- SN neurons normally prevent activation of inhibitory neurons within the basal nuclei
- loss of the SN results in a decrease of movement due to a net increase of inhibitory neuron activation in the BN
Superior Colliculus
vision - coordination of eye movements
Inferior Colliculus
Audition - sound localization
Periaqueductal grey (PAG)
descending pain modulation
Cerebral aqueduct
CSF flow through midbrain
red nucleus
motor control
medial lemniscus
sensory processing
reticular fomation
alertness
cerebral peduncles
white matter tracts of motor pathway (pyramidal tract)
Substantia nigra
motor control (via basal nuclei)
Locate/name structures of the pons
pons
pontine nuclei
respiratory center
medial lemniscus
sensory processing
pyramidal tract
white matter tracts of motor pathway
reticular fomation
alertness
cerebellar peduncles
white matter tracts that project between the brainstem and cerebellum
fourth ventricle
CSF flow
Locate/name the structures of the medulla
medulla
olivary nuclei
motor control
fourth ventricle
CSF flow
Choroid plexus
CSF production
Medial lemniscus
sensory processing
nucleus ambiguus
cardiovascular center
solitary nucleus
cardiovascular and respiratory center
pyramids
white matter motor tracts (voluntary)
Reticular formation
alertness
What is the function of the brainstem reticular activating system (RAS)
regulate consciousness, sleep and arousal
How does the RAS system work
- sensory axons synapse on reticular activating system (RAS) neurons in the brain stem
- Visual impules
- Auditory impulses
- Ascending general sensory tracts (touch, pain, temperature, NO olfaction)
- RAS neurons relay sensory stimuli to the cerebrum through the thalamus
- the continuous stream of sensory stimuli keeps the cerebrum aroused and alert
Vermis
axial control
What do descending projections do
from reticular formation nuclei to the spinal cord
- help to regulate skeletal and visceral muscle activity
Structure of cerebellum
- outer cortex w/groves (fissures) and ridges (folia)
- 2 hemispheres w/lobes separate by a central grove
anterior lobe
primary fissure
horizontal fissure
posterior lobe
vermis
lateral hemsphere
appendicular control
flocculonodular lobe
eye movements
In which way does cerebellar processing and motor control occur
ipsilateral fashion
What are the three sensory inputs to cerebellum
- vision (unfiltered)
- vestibular (balance)
- proprioception (position sense)
- receptors in joints and muscles (close eyes, position…)
What are the major input and output tracts
deep cerebellar nuclei
cerebellar peduncles
Superior cerebella peduncle
cerebellum to brainstem (muscle tone) and cortex (corrective) from deep nuclei
Mid cerebellar peduncle
cortex to cerebellum (motor and visual input)
Inferior cerebellar peduncle
proprioceptive & vestibular input to cerebellum
CN VIII
Vestibular nerve
muscle contractions
Cochlear Nerve
hearing
balance
CN XII
hypoglossal nerve
- tongue muscle movements
CN III
oculomotor nerve
- eyeball + eyelid movement
