mod 1 Flashcards
cerebral hemispheres + diencephalon
forebrain
midbrain, pons, medulla
brainstem
pons, medulla
hindbrain
outer meningeal layer
dura mater
middle meningeal layer
arachnoid mater
inner meningeal layer
pia mater
central sulcus
separates frontal and parietal
lateral sulcus
separates temporal from parietal and frontal
parieto-occipital sulcus
separates parietal and occipital
transverse fissure
separates temporal from cerebellum
location of conus medullaris
at the termination of spinal cord - after L1
location of cauda equina
collection of nerve roots at the inferior end of the vertebral canal after L3
filum terminale
anchors the spinal cord so it sits nicely in the vertebral canal
location of white and grey matter
in spinal cord - grey is central located and white is peripherally
opposite in brain
posterior
dorsal
anterior
ventral
dorsal root
afferent fibres
ventral root
efferent fibres
Paresthesias
sensory loss
high tetraplegia is damage to what
C1 to C4
low tetraplegia is damage to what
C5 to C8
damage to thoracic, lumbar, or sacral injuries
paraplegia
damage to left ventral horn
paralysis on right side
damage to right dorsal horn
sensory loss on left side
outer layer of dura mater
periosteal
inner layer of dura mater
meningeal
what creates the brains folds
folding of the meningeal
falx cerebri
separates two cerebral hemispheres
tentorium cerebelli
separates cerebellum + cerebrum
falx cerebelli
two cerebellar hemispheres
subdural space
space between dura mater and arachnoid mater, very narrow contains film of fluid
how is arachnoid mater connected to pia mater
by fine strands of connective tissue (arachnoid trabecular)
arachnoid villi
knoblike projections of the arachnoid mater
arachnoid granulations
aggregations of arachnoid villi that drain CSF into venous sinuses
4 cisterns of importance
- interpeduncular cistern
- pontine cistern
- superior cistern
- cerebellomedullary cistern
cistern
enlarged subarachnoid space
pia mater
sends prolongations into brain tissue along with blood vessels forming perivascular space, helps form the roof of the ventricles closely associated with choroid plexus and ependyma
which layer of of dura mater does the spine not have
no periosteal layer
epidural space
space between spinal dural sheath and vertebral bony wall, contains fat and venous plexus, largest at L2 for anesthesia
lumbar cistern
inferior to spinal cord below L1 for lumbar puncture to sample CSF
denticulate ligament
supports spinal cord within dural sheath down into the filum terminale
meningitis
inflammation of pia mater and arachnoid mater
midbrain
help to anchor the cerebrum to the brainstem.
contains the oculomoter nerve (anteriorly) and trochlear nerves (posteriorly) and cerebral peduncles
superior colliculi
visual rely and reflex centres
inferior colliculi
auditory relay and reflex nuclei
substantia nigra
located deep to cerebral peduncle
functionally linked to basal nuclei/ganglia
contains melanin pigment
red nucleus
lies deep to the substantia nigra
rich blood supply and contains iron pigment
relay nucleus in some descending motor pathways
pons has
trigeminal, abducens, facial and vestibulocochlear nerves and the 4th ventricle
pyramidal decussation
axons of pyramidal tracts cross over to the opposite side at the level just above the medulla-spinal junction (at level of foramen magnum)
medulla role
maintains body homeostasis, containing the cardiac, respiratory and other reflex centres. has functional association with the hypothalamus
interventricular foramen
links the lateral with the third lateral
cerebral aqueduct
links the 3rd ventricle with the 4th ventricle
fourth ventricle
between cerebellum and pons/medulla
2 lateral apertures, and one median aperture
CSF circulation
produced in choroid in lateral ventricle –> through interventricular foramen to third ventricle –> through cerebral aqueduct to 4th ventricle –> exits at median aperture or down to spinal cord –> from median aperture to cistern magna –> arachnoid villi –> superior sagittal sinus
hydrocephalus
enlarged head in newborn baby, an excessive amount of CSF in ventricular system due to issues with circulation or absorption into venous sinus
10 seconds of interruption of blood flow
cause unconsciousness
1 to 2 minutes of interruption of blood flow
can impair neural function
4 minutes of interruption of blood flow
irreversible brain damage
common carotid artery divides into
external and internal carotid artery
what does external and internal carotid artery supply to
external supplies to face, internal supplies to brain
what does the internal carotid artery divide into
the anterior and middle cerebral artery
circle of willis
basal artery connects to internal carotid artery (via posterior communication arteries)
circle of willis function
maintain blood supply to entire brain if 1 artery gets blocked
what does posterior cerebral artery supply
the medial aspect of the hemisphere (1/3), occipital lobes, inferior temporal lobe regions, brainstem, 3rd and lateral ventricles
what does the middle cerebral artery supply
almost all the lateral surface of cerebral hemisphere
what does the cerebral artery supply
the medial aspect of cerebral hemispheres (2/3) and basal nuclei
occlusion of anterior cerebral artery results in
contralateral hemiplegia (one artery) or bilateral paralysis (2 arteries) and impaired sensation in lower limb greatest
occlusion of middle cerebral artery
a severe contralateral hemiplegia and impaired sensation mostly in upper limb and face
damage to dominant hemisphere during occlusion to middle cerebral artery
other hemisphere (left) will have motor problems with inability or severe problems with speech
occlusion of posterior cerebral artery
contralateral homonymous hemainopsia
venous drainage of the brain
fine veins -> pial venous -> cerebral veins -> dural venous sinuses -> internal jugular vein -> heart
pial venous plexuses
mass group of veins within the pia mater
olfactory nerve
SENSE smell, pass through cribform plate of ethmoid bone
optic nerve
SENSE - vision, passes through optic foramen
oculomotor nerves
MOTOR - (emerge from ventral midbrain) moves eyeballs, constricts pupil, passes through superior orbital fissure
levator palpebrae superior muscle does what
raise upper eyelid
trochlear nerve
MOTOR - (emerge from dorsal membrane) eye movement (rotation downward + laterally), passes through superior orbital fissure
trigeminal nerves V1
ophthalmic division - vision, axons run from face to pons via superior orbital fissure (SENSORY)
trigeminal nerves V2
maxillary division, axons run from face to pons via foramen rotundum (SENSORY)
upper teeth, palate, skin cheek and upper lip, nasal cavity
trigeminal nerves V3
mandibular division, pass through skull via foramen ovale. (SENSORY to anterior tongue,
lower teeth, temporal region of scalp)
(MOTOR to carry proprioceptor axons from muscles of mastication)
impaired chewing would be due to which cranial nerve
trigeminal nerve
abducens nerve
MOTOR - abducts eyeball, leave inferior pons to pass through superior orbital fissure
droopy eyelids is damage to what
oculomoter nerves
facial nerves
SENSORY AND MOTOR from pons to temporal bone via internal auditory meatus
5 branches of facial nerves
temporal - temporal region
zygomatic - zygomatic bone
buccal - cheek region
mandibular - mandible
cervical - neck region
bells pasly or distrubed sense of taste is damage to what
facial nerves
facial (motor)
to skeletal muscles of face except chewing
facial (sensory)
impulses from taste buds of anterior 2/3 of tongue
vestibulocochlear nerves
SENSORY, pass through intneral acoustic meatus
nystagmus, deafness, dizziness damage of what
vestibulocochlear nerves
glossopharngeal nerves
SENSORY and mOTOr through jugular foramen
sensory - posterior 1/3 of tongue
motor - axons to pharyngeal muscle - stylopharyngeus
vagus nerve
sensory and motor, jugular foramen
motor - skeletal muscles of pharynx and larynx
sesnory-abdominal viscera, pharynx, carotid sinus?
only cranial nerve to extend beyond head and neck to thorax and abdomen
vagus nerve
hoarseness of loss voice, impaired swallowing, digestive system mobility damage to
vagus nerve
accessory nerves
MOTOR jugular foramen, supplies axons to trapezius and sternocleidomastoid muscles for neck shoulder movement
unable to shrug/move head/neck/shoulder damage is due to
accessory nerves
hypoglossal nerve
MOTOR, hypoglossal canal, motor axons to intrinsic and extrinsic muscles of tongue (for movements of speech, food manipulation, swallowing)
damage to causes difficulties in speech and swallowing
one side - tongue deviates
both sides - inability to protrude tongue
hypologossal nerve
nonfluent aphasia
damage to brocas area
fluent aphasia
damage to wernickes area
reticular formation
involved in habituation, composed of clusters fo grey matter scattered through brainstem
can be inhibited by sleep centres located in hypothalamus
arbor vitae-tree of life
white matter
cerebellum primary concern
posture, balance, movement across multiple joints
how synergistic multijoint movement is achieved
- premotor cortex inform to start voluntary muscle contraction
- cerebellum receives information from proprioceptors
- information includes tension in muscles/joints
- cerebellum evaluates body position and momentum
- calculates best way to coordinate
- coordinates movement
what connects the right and left hemisphere of the cerebellum
vermis
two main inputs of the cerebellar circuits
mossy fibres (from spinal cord) and brainstem neurons
what do mossy axons form excitatory synapses with in the cerebellar cortex?
granule neurons
the sole output neuron from the cerebellar cortex
purkinje neuron
vermis function regions and the deep cerebellar nuclei
projects to fastigal nucleus
intermediate zone of the function regions and the deep cerebellar nuclei
projects to the interposed/interpoisitus nucleus
lateral zone of the functional regions and the deep cerebellar nuclei
projects to the dentate nucleus
motor input of cerebellum
corticopontine tract goes onto the cerebellum to form the corticopontine cerebellum tract
sensory input of cerebellum
spino-olivary tract -> inferior olivary nucleus -> lateral zone -> dentate nucleus -> red nucleus -> thalamus -> primary motor cortex (then output via lateral corticospinal tract)
spinocerebellar intermediate zone circuits
controls accuracy of movement of limbs e.g. precision at a joint
spinocerebellar medial/median/vermal zone circuit
controls posture via influencing axial muscles in trunk
vestibulocerebellar circuits
maintain balance via axial limb muscles
inferior cerebellar peduncle
conveys sensory information to the cerebellum
middle cerebellar peduncle
contains only afferent axons
superior cerebellar peduncle
connects cerebellum to midbrain
ataxia
inaccuracy in speed, force and distance of movement
tremor
involuntary oscillation of the limbs or trunk
nystagmus
rhythmic voluntary oscillation of the eyes
headache+vomiting
blockage of CSF drainage from 4th ventricle
projection tracts
extend vertically from brain to spinal cord, forming internal capsule
commissural tracts
cross from one hemisphere to the other
anterior commisure
includes axons that connect the middle and inferior temporal gyri of the two sides
association fibres
connect lobes and gyri within the hemishpere
putamen + globus pallidus
lentiform nucleus
lentiform nucleus + caudate nucleus
corpus striatum
corpus striatum + subthalamic nuclei + substantia nigra
basal ganglia
putamen + caudate nucleus
striatum
basal ganglia function
motor control
parkinsons disease
substantia nigra dopamine neuron degeneration
forms the superolateral walls of the third ventricle
thalamus
epithalamus
generates melatonin
taste
lower end of postcentral gyrus
smell
medial temporal uncus and orbitofrontal lobes
vision
occipital lobe
hearing
superior temporal lobe
equilibrium
mainly to the cerebellum
mechanoreceptors
sensitive to mechanical force e.g. touch pressure, vibration
thermoreceptors
are sensitive to temperature change
photoreceptors
respond to light energy
chemoreceptors
respond to chemicals in solution
nociceptors
respond to potentially damaging stimuli that result in pain
exeroreceptors
sensitive to stimuli arising outside of body
interoreceptors / visceroceptors
are sensitive to stimuli within the body
proprioceptors
are sensitive to internal stimuli
gracile tract
medial - carriers impulses from lower limbs and inferior body trunk
cuneate tract
lateral - transmits afferent impulses from upper limbs, trunks and neck
processing at receptor level
detect stimuli -> transduction -> propagation
anterior spinothalamic pathway
transmits impulses concerned with crude touch and pressure to opposite somatosensory cortex
lateral spinothalamic pathway
first order: dorsal root ganglion
2nd order: dorsal horn of spinal cord
cross in spinal cord
3rd order: thalamus
concerned with pain and temperature
spinocerebellar pathways
no cross over and no third oder neuron, axons go straight to cerebellum rather than thalamus
1st order: dorsal root ganglion
2nd order: dorsal horn neuron
dorsal column pathway
first order: dorsal root ganglia
2nd order: nucleus gracillis and cuneatus
cross at medulla
3rd order: thalamus
dorsal column injury
loss of fine touch and conscious proprioception on same side below site of injur
injury on left anterolateral side
loss of pain and temperature on right side
injury on right posterolateral side
loss of unconscious proprioception to the cerebellum from right side of the body
cortical motor areas
produce direct pyramidal system
brainstem motor areas
oversee the indirect (extrapyramidal) system
direct pyramidal system (concerned with voluntary movments)
PMC -> internal capsule -> cerebral peduncle -> pyramids cross over -> down lateral tract
damage to corticospinal tract at any level
paralysis of target muscles
lesion above pyramidal decussation on right
paralysis of left upper limb and lower limb muscles
lesion below the pyramidal decussation in left lateral T10 spinal cord
paralysis of left lower limb muscles
indirect extrapyramidal system four major nuclei
superior colliculus, red nucleus, reticular formation in pons and medulla, vestibular nuclei in medulla
tectospinal tract
move head and neck and visual input
rubrospinal tract
maintain muscle tone
reticulospinal tract
initiates CPG in spinal cord
vestibulospinal tract
maintain balance
command nerons in brainstem nuclei
start/stop. and regulate posture and balance
ascending tracts
dorsal white column: gracile and cuneate fasciculus
spinocerebellar tracts: dorsal + ventral
spinothalamic tracts: lateral + ventral
descending tracts
corticospinal pyramidal tracts: lateral + ventral
rubrospinal tract
reticulospinal tract: medial + lateral
vestibulospinal tract
tectospinal tract