what are the three layers of the meninges
dura mater, arachnoid, pia mater
what are the two layers of the dura mater and what do they do
periosteum - anchors dura mater to skull meningeal dura - mechanical support and strength to brain
which layer of the dura mater is in the vertebral column
meningeal dura
where are the venous sinuses found
between the layers of dura mater and separate left and right hemispheres, as well as occipital lobe from the cerebellum
what are the venous sinuses filled with
venous blood
where are the potential spaces and what kind of blood vessel can fill it
epidural space (superficial to peristeom) - meningeal artery subdural space (deep to meningeal layer) - bridging veins
where are the real spaces
-between periosteal and meningeal layer - sagittal fissure - transverse fissure (separates occipital and cerebellum) - venous sinuses
describe the pathway of cerebral spinal fluid
made in lateral ventricle interventricular foramina of Monro 3rd ventricle cerebral aquaduct 4th ventricle foramina magendie --> cisterna magna foramina luschka --> pontine cistern subarachnoid space arachnoid granulations dural venous sinuses
where are the other areas that CSF goes in the body besides the cortex
superior cistern, interpeduncular, pontomedullary, cisterna magna, and lumbar (see lecture for picture)
what is non-communicating hydrocephalus
when flow of CSF is obstructed in the ventricular system
what is a communicating hydrocephalus
when the absorption of CSF is not sufficient to remove fluid being produced
what are arachnoid granulations. what kind if pressure is needed
protrusion of arachnoid into the venous sinus where the CSF in the subarachnoid space can drain into the venous sinuses. CSF pressure must be greater than venous pressure
what are the three most common brain herniations
subfalcine, uncal, tonsilar
what is this
epidural hematoma
what is this
subdural hematoma
what is this
subarachnoid hemorrhage
describe the full layers from the scalp to the pia mater
a subfalcine herniation compresses which part of the brain
limbic cortex and comissural
an uncal herniation compresses which brain structures
temporal lobe and midbrain
what are the three layers of the blood brain barrier
arachnoid barrier, choroid/blood CSF barrier, and actual BBB
how does the arachnoid barrier work
arachnoid granulations are considered one-way valves to prevent venous blood from subarachnoid space
how does the blood-CSF barrier
choroidal blood capillaries have fenestrations but tight junctions at the choroid epithelium that prevents blood from entering ventricles
how does the blood brain barrier proper work
tight junctions at the capillary level with astrocytes to help
where is an area where there is no BBB
pineal gland
what are the two arterial supply of the brain (and is it anterior or posterior)
internal carotid (anterior) and vertebral (posterior) artery
what is the venous drainage of the brain
internal jugular vein
the signal from the basal ganglia to the thalamus is (excitatory/inhibitory)
inhibitory
what are the two structures in the red? what is the called overall
Putamen and globus pallidus. Lentiform Nucleus
what are the two structures in blue? what are they called overall
caudate and putamen. Striatum
what is this? what does it do
nucleus accumbens - connection between limbic system and basal ganglia
what is the top blue arrow
subthalamic nucleus
what is the bottom blue arrow
substantia nigra
what are the inputs to the basal ganglia
cerebral cortex, substantia nigra pars compacta, centromedian cortex
what structures outputs the info from the basal ganglia
substantia nigra pars reticulata and globus pallidus internus
what is the effect of the direct pathway on the thalamus (movement, inhibition?, thalamocortical activity)
selective facilitation of movement, disinhibits thalamus, increased thalamocortical activity
what is the effect of the indirect pathway on the thalamus (movement, inhibition?, thalamocortical activity)
selective suppression of movement, inhibits thalamus, decreased thalamocortical activity
what is the pathophysiology of parkinsons
loss dopaminergic neurons of the substantia nigra pars compacta, so there is no dopamine influence on the striatum. leads to a net inhibitory effect on the thalamus
what is the pathophysiology of huntington's disease
-polyglutamine expansion in the huntingtin protein which leads to the STRIATAL degeneration
-indirect-pathway selectively vulnerable
-loss of OUTPUT STRIATAL NEURONS removes the inhibitory effect on the thalamus
what is the dysfunction of the cerebellum
ataxia
what are the three functional areas of the cerebellum
1) Flocculonodular lobe/vernis
2) intermediate hemispheres
3) lateral hemispheres
what is the function of the flocculonodular lobe and vernis
coordination of the proximal limb and trunk muscles (like the fasciculus cuneatus) (vermis)
balance (FN)
vestibular-ocular reflex (FN)
what is the function of the intermediate hemisphere
coordinate distal limb muscles and modulate ongoing movement
what is the function of the lateral hemisphere
motor planning
what are the three pairs of peduncles in the cerebellum and do they have afferent or efferent nerves
inferior - afferent and efferent
middle - afferent only
superior - efferent primarily
what are the sources of afferent nerves to the cerebellar peduncles and what information do they bring
vestibular system (balance and head position)
spinal cord (proprioceptive)
pons (cortical info)
what are the three pairs of deep cerebellar nuclei
- fastigial nucleus
- interposed nucleus
- dentate nucleus
where are the dentate and interposed nuclei found
superior penduncle
what intermediate targets does dentate and interposed nuclei send efferent information to
thalamus (VA, VL) and red nucleus
what motor system does the dentate and interposed nuclei modulate
lateral
where is the fastigial nucleus found
inferior peduncle
what intermediate targets do the fastigial nucleus send efferent info to
vestibular, reticular formation, MLF
which motor system does the fastigial nucleus modulate
medial
what kind of muscle coordination is the fastigial nucleus in charge of
eye movements, posture, balance
what kind of muscle coordination is the interposed nucleus in charge of
limb movements (pose for a funny picture!)
what kind of muscle coordination is the dentate nucleus in charge of
skilled learned movements (like how a dentist needs to be skilled)
what is the general pathway to determine cerebellar motor pathways
sensory --> cerebellar functional structure --> cerebellar deep nuclei --> target nuclei --> target
what is the cerebellar pathway for eye movement
vestibular
flocculonodular lobe
fastigial nuclei
vestibular nuclei
MLF
what are the symptoms of impaired cerebellar function of eye movement
impaired vestibulo-ocular reflex
impaired nystagmus
ocular dysmetria (overshoot and undershoot saccades)
what is the cerebellar pathway for postural control
proprioceptive and vestibular
cerebellar vermis
fastigial nucleus
vestibular nucleus
medial motor system (vestibulospinal)
what are the symptoms of impaired cerebellar postural control
impaired ability to sit and stand without support
vertigo
what is the cerebellar pathway for truncal balance
proprioceptive and vestibular
cerebellar vermis
fastigial nucleus
vestibular and reticular formation
medial motor system (vestibulospinal and reticulospinal)
what is the cerebellar pathway for appendicular movement
proprioceptive
intermediate hemisphere
interposed nucleus
VA/VL
lateral motor system
what are the symptoms of cerebellar dysfunction of appendicular movement (ataxia)
- impaired on finger-nose-finger task
- impaired on heel-shin test
- impaired rapid alternating movements
- incoordination during limb movement
what is the cerebellar pathway for learned skilled movements
pontocerebellar
lateral hemisphere
dentate nucleus
VA/VL nuclei
lateral motor system
what are the symptoms of cerebellar dysfunction of learned skilled movements
- impaired rapidity & precision of performing skilled movements (e.g.playing piano)
- impaired ability to learn new skilled motor tasks