Module 1: Neuroanatomy Flashcards
what are the 4 main subdivisions of the brain?
forebrain, midbrain, hindbrain and cerebellum
what structures make up the forebrain?
cerebrum hemispheres and diencephalon
what structures make up the midbrain?
brainstem and middle of the brain
what structures make up the hindbrain?
pons and medulla of the brainstem
where are 50% of the brain’s neurons found?
cerebellum
what would a lateral view of the brain picture?
the brain from the side, either left or right
what would a coronal view of the brain picture?
a cross section through the brain, often pictures deep
what would a sagittal view of the brain picture?
view from the top down of the brain
what is the midsagittal line?
the line that goes down the middle of the brain; slightly curved
what are neurons?
highly specialised, excitable cells that provide rapid and specific communication between regions of the body
what are glia cells?
cells that give structural support and insulation in the nervous system
what are the 4 types of glia cells?
astrocytes, microglia, ependymal cells and oligodendrocytes
what is grey matter and where is it found in the brain?
collections of cell BODIES found on the outside of the brain
what is white matter and where is it found in the brain?
collections of cell AXONS found on the inside of the brain
what are gyri?
the upper part of folds in the brain
what are sulci?
the lower part of folds in the brain
what is a fissure in the brain?
a deep sulcus in the brain
what are the 5 lobes of the brain?
frontal lobe, parietal lobe, occipital lobe, temporal lobe and the insula
what is the insula?
a lobe deep inside the brain that forms the foundation of other lobes such as the frontal, parietal and temporal lobes
what is the central sulcus?
divides the frontal and parietal lobes
what separates the cerebrum from the cerebellum?
transverse fissure
what separates the temporal lobe and the frontal lobe?
the lateral sulcus
what separates the parietal and occipital lobes?
parietal-occipital sulcus
what is the foramen magnum?
hole in the base of the skull through which the brain connects to the spinal cord
how many spinal nerves are in each of the parts of the spinal cord (31 total)?
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
what are the names of the 2 enlargements in the spinal cord?
cervical enlargement and lumbar enlargement
why are there enlargements in the spinal cord?
they contain motor neurons responsible for the movement of the upper limbs (cervical) and the lower limbs (lumbar)
what is the conus medullaris/medullary cone?
the end of the spinal cord that sits under the lumbar enlargement
what is the filum terminale ?
extends from the medullary cone to the end of the coccyx as an anchor to allow the spinal cord to stand straight
what is the cauda equina?
a collection of nerve endings at the end of the vertebral canal
why does the cauda equina exist?
because the vertebral column grows faster than the spinal cord, so it is longer than the sc
grey matter in on the inside of the spinal cord T/F
true, white matter is on the outside to protect the grey matter, opposite to the brain
where is the anterior median fissure found in the spinal cord?
at the anterior-middle of the spinal cord
where is the posterior median sulcus found in the spinal cord?
at the posterior-middle of the spinal cord
how does sensory information enter the spinal cord (afferent)?
through the dorsal roots
how does motor information leave the spinal cord?
through the ventral roots
what structures have a MIX of afferent and efferent fibres from the spinal cord?
spinal nerves
what is paralysis?
loss of motor function
what is parathesis?
loss of sensory feeling
what is high tetraplegia and what causes it?
loss of functioning of upper and lower limbs and potentially loss of breathing ability, caused by damage to C1-C4
what is low tetraplegia and what causes it?
some of functioning of upper and lower limbs without the risk of losing breath, caused by damage to C5-C8
what is paraplegia and what causes it?
loss of functioning in legs, caused by damaged to the thoracic, lumbar or sacral spinal cord
damage to the left ventral horn of T1 would cause ??
loss of motor functioning in right leg
what is the purpose of meninges in the brain?
to protect the brain and spinal cord
what is the dura mater?
the first layer of meninges, very tough
what are the 2 layers of the dura mater?
periosteal and meningeal layers
how are venous sinuses formed in the brain?
the separation of the periosteal and meningeal layers of the dura mater
what do the venous sinuses do in the brain?
drain the brain of fluids
which layer of the meninges is repeatedly folded to cause partitions between regions of the brain?
meningeal layer of the dura mater
what 2 regions are separated by the falx cerebri?
two cerebral hemispheres
what 2 regions are separated by the tentorium cerebelli?
the cerebrum and cerebellum
what 2 regions are separated by the falx cerebelli?
the two cerebellar hemispheres
what are the 3 layers of the meninges?
- dura mater
- arachnoid mater
- pia mater
where is there subdural space in the brain?
between the dura mater and arachnoid mater, filled with some fluid
what happens if the subdural space fills with blood?
subdural haemorrhage
how is the arachnoid mater different from the pia mater?
the arachnoid mater doesn’t dip into the sulci like the pia mater does
what do arachnoid trabecula do?
fine strands of connective tissue that connect the arachnoid mater to the pia mater and are in the subarachnoid space
what do arachnoid villi do?
stretch into sinuses to drain the CSF to and from the sinuses around the rest of the brain
what are arachnoid granulations?
collections of arachnoid villi
what are cisterns in the brain?
enlarged subarachnoid spaces that hold CSF around the brain
where in the brain sits the cisterna magnum/cerebellomedullary cistern?
inferior to the cerebellum
where is CSF extracted from in newborns to check for meningitis/infection?
cisterna magnum
where in the brain sits the superior cistern?
superior to the cerebellum
where in the brain sits the interpeduncular cistern?
anterior to the midbrain
where in the brain sits the pontine cistern?
anterior to the pons, smallest cistern in brain
what meninges layer is associated with the perivascular space?
pia mater, the space where pia mater and blood vessels join to supply the brain with blood
what are the layers of the spinal cord meninges starting from the spinal cord out?
spinal cord - subarachnoid space - arachnoid mater - dura mater - epidural space (and pia mater)
why does the spinal cord dura mater only have one layer of dura instead of 2?
because the spinal cord requires greater range of movement than the brain does
where does the main source of protection of the spinal cord come from?
epidural layer (fats and venous plexus)
where is the epidural space the largest in the spinal cord and what is this used for clinically?
L2; to inject epidural anaesthesia to women giving birth
what is the lumbar cistern?
a cistern in the spinal cord where a lumbar puncture can be inserted to extract CSF
what is the function of denticulate ligament in the spinal cord?
a pia mater layer that horizontally supports the spinal cord
what is the function of filum terminale in the spinal cord?
a pia mater layer that vertically supports the spinal cord
what is meningitis?
the inflammation of the pia and arachnoid maters
what are the 4 ventricles called?
2 lateral ones, third and fourth
which ventricles does the inter-ventricular foramen connect?
lateral ventricles to the third ventricle
which ventricle does the cerebral aqueduct connect?
third ventricle to the fourth ventricle
what are the 3 horns that the lateral ventricles have and which lobes are these each near?
anterior - frontal
inferior - temporal
posterior - occipital
what is the choroid plexus and where is it found in the brain?
where CSF is made; found in the ventricles
what are the 3 openings CSF is able to leave the fourth ventricle through called?
- either of the 2 lateral apertures
- median aperture
what is the superior medullary velum?
the roof of the fourth ventricle
what is the main purpose of CSF in the brain?
to decrease the weight of the brain by 97% and prevent the brain from collapsing in on itself
what is the sequence of CSF flow through the brain in
1) produced in the choroid plexus
2) third ventricle
3) fourth ventricle
4) into cisterna magma or to other side of brain or into the central canal (to spinal cord)
5) to the sinuses at the top of the brain
what forms the blood-brain barrier?
tight junctions between the endothelial cells of the cerebral capillaries which allows for only a select few things to get through to the brain
what is hydrocephalus?
enlarged ventricles due to overproduction of CSF in the brain
what are the 2 main arteries that travel up the neck to supply blood to the brain?
- internal carotid artery
- vertebral artery
where does the external carotid artery supply blood to?
the face
does the internal carotid artery supply to the anterior or posterior part of the brain?
anterior
does the vertebral artery supply to the anterior or posterior part of the brain?
posterior
what artery do the two vertebral arteries join to form?
basilar artery
what arteries do the basilar artery split into?
posterior cerebral arteries
what arteries does the internal carotid artery split into?
anterior cerebral artery and the middle cerebral artery
what are the 3 major arteries that supply blood to the brain (within the Circle of Willis) ?
anterior, middle and posterior cerebral arteries
what arteries connect the posterior cerebral arteries to the internal cerebral arteries?
posterior communicating arteries
what artery connects the two anterior cerebral arteries?
anterior communicating arteries
which part of the brain do the posterior cerebral arteries supply blood to?
the medial aspect of the brain (occipital lobe and brainstem)
which part of the brain do the middle cerebral arteries supply blood to?
most of the lateral sides of the brain (frontal, parietal, temporal lobes)
which part of the brain do the anterior cerebral arteries supply blood to?
most of the upper areas of the frontal and parietal lobes (higher order)
damage to the posterior cerebral arteries can cause:
occipital lobe damage and problems with vision
damage to the middle cerebral arteries can cause:
severe contralateral hemiplegia in the upper limbs and face due to damage to these neurons in the motor cortex
damage to the anterior cerebral arteries can cause:
contralateral hemiplegia in the lower limbs due to damage to these neurons in the motor cortex
what do the fine veins do in draining the blood from the brain?
sit in the brain tissue and drain blood from the brain
what is the order of blood drainage in the brain?
fine veins < pial venous plexus < cerebral veins < dural venous sinuses < internal jugular vein < heart
which meninges layer is the pial venous plexus a part of?
pia mater
what is the name of the main vein in the neck that carries blood from the brain to the heart?
internal jugular vein
what do the emissary veins do?
bring blood from the scalp into the dural venous sinuses
what are venous sinuses?
large veins that sit between the periosteal and meningeal layers of the dura mater in the brain to store blood and CSF
where does the superior sagittal sinus sit?
along the superior margin of the falx cerebri
which sinus does the superior sagittal sinus drain into?
transverse sinus
where does the inferior sagittal sinus sit?
along the inferior margin of the falx cerebri
which sinus does the inferior sagittal sinus drain into?
straight sinus
where does the straight sinus sit?
within the tentorium cerebelli
which sinus does the straight sinus drain into?
left transverse sinus
where do the transverse sinuses sit?
runs along the transverse plane at the back of the brain
what is the point where the transverse sinus meets the superior sagittal sinus called?
confluens
which sinus does the left transverse sinus drain into?
Sigmoid sinus
where does the Sigmoid sinus sit?
close to the brainstem
which sinus does the Sigmoid sinus drain into?
the internal jugular vein
what sinus surrounds both sides of the pituitary gland?
cavernous sinuses
what sinuses do the cavernous sinuses drain into?
either the superior petrosal sinus (to transverse sinus) or the inferior petrosal sinus (internal jugular vein)
how can emissary veins expose the body to dangerous infections?
bacteria from the scalp can enter the sinuses through the emissary veins and into the brain
where do the ophthalmic veins drain blood from and drain into?
the nose and upper lips; drain into the cavernous venous sinuses
what are the three gyri that make up the frontal lobes?
- superior frontal gyrus
- middle frontal gyrus
- inferior frontal gyrus
what are the two sulci that separate the gyri in the frontal lobe?
superior frontal sulcus and the inferior frontal sulcus
what are the three divisions of the inferior frontal gyrus?
the opercular, triangular and orbital
what areas makeup Broca’s area?
the inferior frontal gyrus, opercular and triangular
what does the premotor cortex do?
PLANS movements and controls learned motor skills; damage here means you have trouble with movements
what is the prefrontal cortex involved in?
intellect, complex learning, cognition, recall and personality; damage leads to personality and mental disorders
what are the two alternative motor areas of the brain?
the supplementary motor area and the Cingulate gyrus ‘ damage to these areas leads to loss in SKILLED movements and speech
what are the two sagittal lobules of the parietal lobe?
superior parietal lobule and the inferior parietal lobule
what sulcus separates the superior and inferior parietal lobules?
intraparietal sulcus
what are the 2 gyri that make up the superior parietal lobule?
supramarginal gyrus and angular gyrus
what does the superior parietal lobule do?
integrates sensory information to produce a good understanding ie how we feel something without looking at it
what is the main sulcus that runs through the middle of the occipital lobe called?
Calcarine sulcus
what are the divisions of the temporal lobe?
superior, middle and inferior temporal gyri
what are the sulci that divide the temporal lobe called?
superior and inferior temporal gyri
what separates the inferior temporal gyrus from the middle temporal gyrus ?
occipitotemporal sulcus and the Rhinal sulcus
what separates the middle temporal gyrus from the superior temporal gyrus?
Collateral culcus
where is the amygdala found and what is its other name?
superior temporal gyrus; uncus
what are the white matter tracts of the hippocampus called?
fimbria and formix
what does the septum pellucidum do?
separates the lateral ventricles
what is Wernicke’s area responsible for?
perceiving spoken language and helping create plans of spoken response
what is another name of the primary auditory cortex?
primary auditory cortex
what does damage to Broca’s area cause?
non fluent aphasia
what does damage to Wernicke’s area cause?
fluent aphasia
what is fluent aphasia?
normal speech. is made just without meaning
where do the projection tracts lead in the brain?
from the cerebral cortex to the spinal cord
what is the internal capsule?
the channels created by projection tracts that direct axons towards the spinal cord
where do the commissural tracts lead in the brain?
axon tracts that cross between hemispheres, especially in the corpus callosum
what are the 4 divisions of the corpus callosum?
- genu (anterior frontal)
- rostrum (anterior frontal)
- body (posterior frontal and others)
- splenium (temporal and occipital)
what are the two ways you can be a split brain patient?
- acollosal (born w/o one)
- corpus callosum transection surgery in epilepsy patients
what are the association tracts in the brain?
connect the lobes and gyri within the SAME hemisphere
what are the two parts of the lentiform nucleus?
putamen and globus pallidus
what are the two parts of the corpus striatum?
caudate nucleus and lentiform nucleus
what are the 3 components of the basal nuclei?
corpus striatum, subthalamic nuclei and the substantia nigra
what is at the end of the tail of the caudate nucleus?
amygdala
what runs through the lentiform nucleus of the basal ganglia?
internal capsule
which two structures does the anterior limb of the internal capsule run through in the basal nuclei?
between the lentiform nucleus and the caudate nucleus
which two structures does the posterior limb of the internal capsule run through in the basal nuclei?
lentiform nucleus and the thalamus
what is the main function of the basal nuclei?
regulates movement, especially the initiating of movement
what causes Parkinson’s disease?
depletion of dopamine in the substantia nigra of the brain
treatments of Parkinson’s
- replacement of dopamine
- stem cell therapy
- DBS
what are the 3 structures that make up the diencephalon?
thalamus, hypothalamus, epithalamus (pineal gland)
what structure joins the right and left thalami?
inter-thalamic adhesion
what structure makes up 80% of the diencephalon?
thalamus
what structure separates the hypothalamus and the thalamus?
hypothalamic sulcus
what structure extends from the optic chaism in the diencephalon?
hypothalamus
main function of the hypothalamus?
maintaining body homeostasis
which wall of the third ventricle does the epithalamus help form?
the roof
why is the presence of pineal sands in the pineal gland of adults important?
appears opaque in neuroimagery
what structure produces melatonin?
pineal gland
how many pineal glands are in the brain?
1
what are the parts of the brainstem?
midbrain, pons and medulla
how many pairs of cranial nerves is the brainstem associated with?
10
what are the cerebral peduncles?
axons that join and anchor the cerebrum to the brainstem
what 2 cranial nerves are associated with the midbrain?
cranial nerve 3 and cranial nerve 4
what are the superior colliculi and what are they associated with?
bulbs in the midbrain that receive inputs from the retina to track movements
what are the inferior colliculi and what are they associated with?
bulbs in the midbrain that relay auditory information to the ear about reflexive sounds eg the startle reflex
what are the cerebellar peduncles?
they connect the brainstem to the cerebellum (superior and middle and inferior)
what is the substantia nigra?
structure in the midbrain that holds most of the dopamine in the brain, is black (melanin pigment)
what structure holds the dopamine in the substantia nigra?
pars compacta (SNpc)
what structure of the substantia nigra has connections with the globus pallidus of the basal nuclei?
pars reticulata (SNpr)
what cranial nerves are associated with the pons?
- trigeminal
- abducens
- facial
- vestibulocochlear
what do the pontine nuclei do in the pons?
composed of ascending and descending axon tracts which carry information about maintain homeostasis
what are the pyramids in the medulla?
pyramidal axons that make up the motor corticospinal tract that descends from the motor cortex
where do the axons of the corticospinal tract cross?
just above the medulla-spinal junction
what do the olives do in the medulla?
relay sensory information to the cerebellum
what is the fasciculus gracilis?
a bundle of axon fibres in the medulla that carry sensory information from the lower limbs into the brain
what is the fasciculus cuneatus?
a bundle of axon fibres in the medulla that carry sensory information from the upper limbs into the brain
what major role does the medulla have?
maintaining homeostasis
what are the 12 cranial nerves?
olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory and hypoglossal
what are the olfactory cranial nerves and how do they work?
- sensory nerves in the nasal cavity that help us smell
- nerves sit through holes in the cribriform plate of the ethmoid bone to synapse onto the olfactory bulb –> olfactory tract –> olfactory cortex –> hypothalamus –> hippocampus –> amygdala –> reticular formation
how does the olfactory cortex contribute to the olfactory cranial nerves?
produces our first conscious perception of what we smell
how does the hippocampus contribute to the olfactory cranial nerves?
uses our memory to link the smell to a memory
how does the amygdala contribute to the olfactory cranial nerves?
causes any emotional response we may have to the smell
how does the reticular formation contribute to the olfactory cranial nerves?
causes the visceral responses to the smell eg preparing the stomach for food
each nasal retina sees the ___________ of the visual field and vice versa
temporal
the left side of the retina sees the ______ side of the visual world and vice versa
right
where do the axons cross in the optic cranial nerves?
optic chiasm
where is the LGN?
temporal lobe
what causes bitemporal hemianopsia?
a lesion in the optic chiasm
what sort of nerves are oculomotor nerves?
mixed mainly motor
what is the main function of oculomotor nerves?
to provide most of the movement of the eyeballs and eye lids
what does damage to the oculomotor nerves do?
causes drooping upper eyelid, dilated pupil, double vision, difficulty focussing and the inability to move the eye in some directions
what side do the trochlear nerves emerge from?
the dorsal side (only cranial nerve to do this)
what do the trochlear nerves help manage?
the movement of the eye downward and laterally
what does damage to the trochlear nerves do?
causes double vision and the inability for the eye to rotate inferolaterally
what are the 3 branches of the trigeminal nerves?
ophthalmic division (V1), maxillary division (V2) and the mandibular division (V3)
what are the largest cranial nerves?
trigeminal nerves
what does damage to the trigeminal nerves do?
damage produces a produces loss of sensation and impaired chewing
what is trigeminal neuragia?
inflammation of the trigeminal root, causes excruciating pain, treated by cutting the trigeminal nerve
what do the abducens nerves do?
provide abduction of the eyeball
what does damage to the abducens nerves do?
an inability to rotate the eye laterally
what are the 5 divisions of facial nerves?
temporal, zygomatic, buccal, mandibular and cervical
what are the 2 functions of facial nerves?
- motor nerves for facial expressions
- taste for the anterior part of the tongue
damage to what nerve can cause Bell’s Palsy?
facial nerves
what is the function of vestibulocochlear nerves?
provide hearing and a sense of balance
what is the function of the glossopharyngeal nerves?
aid in swallowing, salivation and taste of the posterior part of tongue
what are some of the functions of the Vagus nerve?
visceral supply, taste buds, skeletal muscles
what are the functions of the accessory nerves?
has the cranial root and spinal root which supply movements for shoulders
