Nauroanatomy Flashcards
Module 1
The cerebellum makes up what percentage of the brains total neurons?
50%
What is a collection of cell bodies in the CNS?
Nucleus
What is a collection of cell bodies in the PMS?
Ganglion
Why does white matter look white?
The fat in the myelin around the axons
Where is the central sulcus?
Between the frontal and parietal lobes
Where is the lateral sulcus?
Separates the temporal lobe from the frontal and parietal
Where is the transverse fissure?
Between the cerebrum and cerebellum
Where is the parieto-occipital sulcus?
On medial surface between parietal and occipital lobes
Where does the spinal cord start?
Foramen magnum
Where does the spinal cord end?
1/2 lumbar vertebra
How long is the spinal cord?
~42 cm
How many pairs of spinal nerves do you have?
31
What are the divisions of the spine?
8 - cervical
12 - thoracic
5 - lumbar
5 - sacral
1 - coccygeal
Where are the two spinal cord enlargements and what are they for?
Cervical and lumbar enlargements, are where the arm and leg nerves leave
What is at the end of the spinal cord?
Conus medullaris connects to filum terminale that attaches to the coccyx
What is the cauda equina?
The nerve roots going down to where they leave the spinal column, runs along side the filum terminale
Why are the spinal cord and spinal column different lengths?
After birth the spinal column keeps growing so the spinal cord is too short
Where is the grey matter in the spinal cord?
In the center (opposite to brain)
Where is the anterior median fissure?
The big groove at the front of the SC where blood vessels sit
Where does information go into the spinal cord?
The dorsal root
Where do the cell bodies of sensory axons coming into the SC sit?
In the dorsal root ganglion
Where does information leave the SC?
The ventral root
What type of neurons are the motor neurons leaving the SC?
Multipolar
What type of neurons are the sensory neurons leaving the SC?
Unipolar
What are the spinal nerves?
The place where the sensory and motor neurons go together out of the spinal column. Are 2-way
What is paresthesia?
Loss of sensory information (due to spinal cord damage)
What does damage between C1-4 do?
High tetraplegia (can’t move any limbs need ventilator)
What does damage between C5-8 do?
Low tetraplegia (can’t move limbs but can breathe by yourself)
What does damage below C8 do?
Paraplegia (can’t move legs)
Can SC injuries be incomplete?
Yes, some info can still get through
When looking at SC sections are left and right flipped?
Yes, look at them from the patients perspective
What does damage to the anterior horn of the SC do?
Paralysis/loss of motor function in that part
What does damage to the dorsal horn of the SC do?
Paresthesia/loss of sensory info from that part
What are the 3 meninges layes?
Pia mater, arachnoid mater and dura mater
What is the subarachnoid space?
Space between arachnoid and pia mater filled with CSF
What is dura mater made out of?
Thick connective tissue
What are the 2 layers of the dura mater?
Periosteal layer (attached to skull) and meningeal layer (attached to arachnoid)
What happens with the 2 dura layers?
Are usually together but sometimes separate so there’s a gap between them, the gap is a venous sinus
What are venous sinuses?
Cavities that drain CSF
Does the dura mater fold into sulci?
No
Does the dura mater fold into fissures?
Yes
Where is the falx cerebri?
Down the longitudinal fissure between the hemispheres
What is the falx cerebri tentorium cerebelli and falx cerebelli made out of?
Dura mater
What does the falx cerebri attach to?
The crista Galli at the top and the tentorium cerebelli at the bottom
Where is the tentorium cerebelli?
Between the cerebrum and cerebellum
Where is the falx cerebelli?
Between the two cerebellar hemispheres
Where is the subdural layer?
Between the dura and arachnoid mater
What is a subdural haemorrhage?
The subdural space is enlarged due to bleeding
Does the arachnoid mater go into sulci?
No
What colour is the arachnoid mater?
Transparent
What connects the arachnoid and pia?
Connective tissue strands called arachnoid trabeculae
What is in the subarachnoid space?
CSF to cushion brain
Which meningeal layer do blood vessels sit on?
On the pia mater in the subarachnoid space
What is a subarachnoid hemorrhage?
Blood vessels in the subarachnoid space are damaged and hemorrhage
What causes concusions?
Caused by damage to the brain after hitting the skull
What are arachnoid villi?
Projections from the arachnoid mater into the venous sinuses to drain CSF
What are aggregations of arachnoid villi called?
Arachnoid granulations
What are cisterns?
Enlargements of the arachnoid space
What are the 4 main cisterns?
Cerebellomedullary/cistern magna, superior cistern, interpeduncular cistern and pontine cistern
Which cistern is the biggest?
Cerebellomedullary/cistern magna
Where is the cerebellomedullary cistern?
Posterior side of brainstem below the cerebellum
Where is the superior cistern?
Posterior side of brainstem between the cerebrum and cerebellum
Where is the interpeduncular cistern?
Anterior side of brainstem above the pons
Where is the pontine cistern?
Anterior side of the brainstem below the pons
Does pia mater fold into the sulci?
Yes!
What is the perivascular space?
The space around blood vessels that go into the brain (between the blood vessels and the pericytes)
Which meningeal layer surrounds the blood vessels going into the brain tissue?
Pia mater
Which meningeal layer forms the walls of the ventricles?
Pia mater
Which meningeal layer is closely associated with choroid plexus?
Pia mater
Is there a periosteal dural layer in the spinal cord?
No
Is there a meningeal dural layer in the spinal cord?
Yes
What is the name of the dural layer in the spinal cord?
The dural sheath
Why is there no periosteal layer in the SC?
For more motility and flexibility
What is the epidural space?
Space between the dural sheath and the bones in the vertebral column
What is in the epidural space?
Fat and venous plexus (network of veins)
Where is the epidural space the largest?
L2
Is there a subarachnoid space in the SC?
Yes
Are there cisterns in the SC?
Yes, the lumbar cistern (not at lumbar enlargement, is below SC)
What is the lumbar cistern used for?
Do lumbar punctures to test CSF
What are denticulate ligaments?
Bits of Pia mater that stabilise the SC laterally within the dural sheath
What is the filum terminale made out of?
Pia mater
What is meningitis?
Inflammation of pia and arachnoid mater caused by bacteria or virus
What are the symptoms of meningitis?
Fever, headache, vomiting and stiff neck
How do you diagnose meningitis?
Test CSF via lumbar puncture to see is bacteria or virus present
What can happen if meningitis isn’t treated?
The infection can cross over the pia mater and damage neurons
What are the ventricles in the brain?
Lateral ventricles, third ventricle and fourth ventricle
What are ventricles?
Spaces in the brain containing CSF
What connects the lateral and third ventricles?
The interventricular foramen
What connects the third and fourth ventricles?
The cerebral aqueduct
How does CSF leave the fourth ventricle?
Via lateral apertures and medial aperture
What are the 3 horns of the lateral ventricles?
Anterior (frontal lobe), posterior (occipital lobe) and the inferior horn (temporal lobe)
What is the choroid plexus?
Cells that produce CSF
Where is choroid plexus found?
Lower wall of the body of lateral ventricles and wraps around to the roof of the inferior horn. Also some in the roof of the 3rd ventricle
What is another name for the lateral apertures in the 4th ventricle?
Foramina of Luschka
What is another name for the median aperture in the 4th ventricle?
Foramen of magendie
Where does CSF go after the 4th ventricle?
Into the subarachnoid space around the brain and SC
What forms the roof of the 4th ventricle?
The superior and inferior medullary velum
Which medullary velum contains choroid plexus?
Inferior medullary velum
How much CSF does your brain make each day?
500ml
Why is CSF important?
Provides chemical stability, buoyancy and protection
Why is buoyancy important in the brain?
So the tissue at the top doesn’t crush the rest (without CSF weighs 1.5kg but only 50g in CSF)
How is the BBB formed?
Tight junctions between epithelial cells
What is the BBB ineffective against?
Fat soluble things
What is hydrocephalis?
Water on the brain, too much CSF in ventricular system so get very big ventricles and brain tissue pushed to side and degrades
What can cause hydrocephalus?
Increased CSF production or disturbances in CSF circulation
How can hydrocephalus cause enlarged heads in babies?
Skulls haven’t properly formed yet
What can blood deprivation do to the brain?
Unconsciousness leading to irreversible brain damage
What are the 2 main arteries going to the brain?
Internal carotid artery and vertebral artey
Where does the internal carotid artery come from?
Common carotid artery splits into internal and external carotid arteries
Where does the vertebral artery come into the brain and what does it form?
Comes in through foramen magnum by vertebral column and 2 arteries form the basilar artery
What does the basilar artery split into?
2 posterior cerebral arteries
What does the internal carotid artery form?
Each artery splits into an anterior and middle cerebral artery
What connects the posterior cerebral arteries and the middle cerebral arteries?
Posterior communicating arteries to form circle of Willis
Why is the circle of Willis important?
So if one artery is blocked can still get some blood to that area
True/false the circle of Willis is exactly the same in everyone?
No it varies between people, one person may have more of a contribution from the vertebral artery and visa versa
What part of the brain does the middle cerebral artery provide for?
Most of the lateral/outer surface
What part of the brain does the anterior cerebral artery provide for?
The anterior 2/3rds of the medial surface
What part of the brain does the posterior cerebral artery provide for?
The posterior 3rd of the brain
What is a cerebral infarction?
Blood flow disruption (stroke)
What happens if one anterior cerebral artery is damaged?
Muscle weakness or paralysis and sensory loss on one side, greatest in lower limbs
What happens if one posterior cerebral artery is damaged?
Contralateral vision effect
What happens if one middle cerebral artery is damaged?
Impaired sensation mainly in upper limbs and face, aphasia if in dominant hemisphere
Where does CSF go after the venous sinuses?
Through the internal jugular vein to the heart
What are emissary veins?
Veins from the face and scalp that also feed into the venous sinuses
Where is the superior sagittal sinus?
Along the superior part of the falx cerebri
What does the superior sagittal sinus connect to?
Right transverse sinus
What parts of the brain does the superior sagittal sinus drain?
Superior and deep structures
Which venous sinus has the most arachnoid villi?
The superior sagittal sinus
Where is the inferior sagittal sinus?
Runs along the inferior part of the falx cerebri
What parts of the brain does the inferior sagittal sinus drain?
Deep and superior structures (same as superior sagittal sinus)
What does the inferior sagittal sinus connect to?
Straight sinus
Where is the straight sinus?
Along the tentorium cerebelli, in the midline
What does the straight sinus connect to?
Left transverse sinus
Where is the transverse sinus?
Below the tentorium cerebelli, runs in the groove in the skull (there’s two)
What do the transverse sinuses connect to?
Right receives from superior sagittal sinus, left receives from straight sinus. Both connect to sigmoid sinuses
What is the confluence?
The point where the superior sagittal, straight and transverse sinuses all come together at the midline
Where are the sigmoid sinuses?
Continue on from the transverse sinuses, form s-shaped grooves in skull
Where do the sigmoid sinuses connect?
From transverse sinuses to internal jugular vein
Where are the cavernous sinuses?
At the front, lateral to the pituitary glands
What structures do the cavernous sinuses drain?
Inferior structures
What do the cavernous sinuses connect to?
Receive from ophthalmic veins and connect to superior and inferior petrosal sinuses
What do the superior petrosal sinuses connect to?
Receive from the cavernous sinuses and drain into the transverse sinuses
What do the inferior petrosal sinuses connect to?
Receive from the cavernous sinuses and drain to the internal jugular vein
What structures do the ophthalmic veins drain?
The eyes
What does the ophthalmic vein drain to?
Cavernous sinuses
What can venous sinus infection cause?
Meningitis
Why is having an infection on your face/scalp bad?
Infection can get into emissary veins and therefore into the sinuses which can cause meningitis. Lower face drained by ophthalmic vein
What gyri make up the frontal lobe?
Precentral gyrus (motor cortex), superior, middle and inferior frontal gyri
What sulci make up the frontal lobe?
The precentral sulcus, superior and inferior frontal sulci
What makes up the inferior frontal gyrus?
The opercular (lips closest to temporal), the triangular (triangle bit in middle) and the orbital (over eyes)
What makes up the Broca’s area?
The opercular and triangular parts of the inferior frontal gyrus
What does the precentral gyrus control?
Voluntary movements
What would happen if you damaged the precentral gyrus?
Contralateral paralysis
Why does blockage/hemorrhage of the anterior cerebral artery cause contralateral hemiplegia and sensory loss greatest in the lower limbs?
Because supplies to medial aspect of front part of the brain, so would damage primary motor and sensory cortices and the lower limbs are located on the medial side
Why does blockage/hemorrhage of the middle cerebral artery cause contralateral hemiplegia and sensory loss greatest in the upper limbs and face?
Provides for the lateral aspect of the brain so will damage the primary motor and sensory cortices on the outside which is mapped to the upper limbs and face
Where is the premotor cortex?
Anterior to the primary motor cortex
What does the premotor cortex do?
Controls learned motor skills
Where is the supplementary motor area?
The top of the premotor cortex (where it bends to the medial side)
Where is the cingulate gyrus?
Medially along the corpus callosum
What would occur if the cingulate gyrus is damaged?
Loss of skilled movement and speech
What sulci are in the parietal lobe?
The postcentral and intraparietal sulci
What gyri are in the parietal lobe?
The postcentral gyrus, the superior and inferior parietal lobules as well as the supramarginal and angular gyri
Where is the supramarginal gyrus?
In the parietal lobe just above the lateral sulcus and just behind the postcentral gyrus
Where is the angular gyrus?
Next to the supramarginal gyrus, above the lateral sulcus in the parietal lobe, more posterior than the supramarginal gyrus
Where is the sensory association cortex?
The superior parietal lobule
What does the sensory association cortex do?
Integrates sensory information so overall understanding of body position and experiences
What would happen if damage the sensory association cortex?
Can only identify objects by looking at them, can’t feel them etc
What sulcus divides the occipital lobe?
Calcarine sulcus
Where is the primary visual cortex?
On either side of the calcarine sulcus
Where is the visual association area?
On either side of the primary visual cortex
What sulci are in the temporal lobe?
The superior and inferior temporal sulci
What gyri are in the temporal lobe?
Superior, middle and inferior gyri
What sulci are on the ventral side of the brain/temporal lobe?
The occipitotemporal, collateral and rhinal sulci
Where is the occipitotemporal sulcus?
Below the inferior temporal gyrus, between it and the rest of the ventral surface
Where is the collateral sulcus?
Curves and joins up with the occipitotemporal sulcus
Where is the rhinal sulcus?
Above the collateral sulcus and parallel to the occipitotemporal sulcus
Where is the parahippocampal gyrus?
On the ventral side of the brain medial to the collateral and rhinal sulci, below the uncus
Where is the uncus?
Above the parahippocampal gyrus, medial to the rhinal sulcus
What is under the uncus (if peel away)?
The amygdala and part of the hippocampus
What is under the parahippocampal gyrus (if peel away)?
The hippocampus
What is the fimbria?
A white matter tract connecting the hippocampus to the fornix
What do the fimbria form?
Two fimbria come together to form the fornix
Where does the fornix go?
Connects to the mamillary bodies
What is the septum pallosidum?
Membrane separating the frontal horns of the lateral ventricles
Where is Wernicke’s area?
The posterior end of the superior temporal gyrus
Where is the primary auditory cortex?
Buried in the lateral sulcus on the superior temporal gyrus
What occurs when there is damage to Broca’s area?
Non-fluent/Broca’s aphasia, know what you’re saying but takes ages to get it out
What is the auditory association cortex called?
Wernicke’s area
What occurs when there is damage to Wernicke’s area?
Fluent/Wernicke’s aphasia, can speak perfectly fine but have no idea what you’re saying
What does the frontal lobe do?
Voluntary movements, language, planning, mood and smell
What does the parietal lobe do?
Sensory reception and integration
What does the temporal lobe do?
Hearing, smell, learning and memory and emotional behavior
What does the insular lobe do?
Possible emotion, homeostasis, cognition, self perception and awareness
What are the 3 types of white matter tracts?
Projection, commissural and association
What are projection tracts?
Project from the brain out to the SC e.g. internal capsule
What are commissural tracts?
Cross from one hemisphere to the other e.g. corpus callosum
Which part of the corpus callosum is the rostrum?
The tail tucked underneath at the front
Which part of the corpus callosum is the genu?
The bend between the rostrum and the body
Which part of the corpus callosum is the body?
The long straightish bit between the genu and the splenium
Which part of the corpus callosum is the splenium?
The back bit
Which parts of the brain do the rostrum and genu of the corpus callosum connect?
The frontal lobes
Which parts of the brain does the splenium of the corpus callosum connect?
The temporal and occipital lobes
Which parts of the brain does the body of the corpus callosum connect?
The rest of the frontal lobe and the parietal lobe
What is split brain treatment?
Cut the corpus callosum to stop spreading of seizures
What is a bad effect of split brain or being born acallosal?
Have trouble identifying things in left hand as info can’t go from right hemisphere to left side with language areas
What is another commissural tract other than the corpus callosum?
Anterior commissure
What does the anterior commissure connect?
The middle and inferior temporal gyri
What are association tracts?
Connect parts of the brain in the same hemisphere
What structures make up the basal ganglia?
Caudate nucleus, putamen, globus pallidus, substantia nigra and subthalamic nucleus
Which structures make up the striatum?
caudate nucleus and putamen
Which structures make up the lentiform nucleus?
Putamen and globus pallidus
Which structures make up the corpus striatum?
The caudate nucleus, putamen and globus pallidus
How does the amygdala relate to the basal ganglia?
Isn’t part of the basal ganglia but the caudate nucleus tail connects to it
What are the parts of the caudate nucleus?
Head (front), body and tail
What are the parts of the internal capsule?
Anterior and posterior limbs as well as a genu/bend
Where are the external and extreme capsules?
On the lateral side of the lentiform nucleus. The external capsule is more medial than the extreme
What separates the external and extreme capsules?
The claustrum
What are the external and extreme capsules?
Projection tracts like the internal capsule
Which part of the lentiform nucleus is more medial?
The globus pallidus
Where do the basal ganglia get information from?
Motor cortex and substantia nigra
Where do the basal ganglia send their information?
Back to the motor cortex via the thalamus
How do the basal ganglia effect movements?
The putamen conically (constantly) sends inhibitory signals to the thalamus so act as a brake
How is the basal ganglia ‘brake’ inhibited?
The substantia nigra excites the putamen which inhibits the inhibitory neurons in the globus pallidus, so disinhibition
What is Parkinson’s disease?
Dopaminergic substantia nigra neurons die so no disinhibition and hard to start movements. Also hard to stop unnecessary movements
What makes up the diencephalon?
The thalamus, hypothalamus and epithalamus
What part of the third ventricle does the thalamus make up?
The superolateral walls
What makes up the thalamus?
Lots of nuclei divided into groups
What is the name of the thing connecting the thalami?
The interthalamic adhesion
What sulcus separates the thalamus and hypothalamus?
The hypothalamic sulcus
What part of the 3rd ventricle does the hypothalamus form?
The inferolateral wall
What does the hypothalamus do?
Neuronal control of the pituitary gland
What does the pituitary gland control?
Lots of homeostatic processes e.g. body temperature regulation, sleep/wake cycle, regulation of food intake etc.
What happens to a rat with no hypothalamus?
Couldn’t release leptin and became obese
What is the most common cause of hypothalamus damage?
Tumor in pituitary gland effects hypothalamus
What are the first symptoms of a tumor in the pituitary gland?
Visual defects as the tumor presses on the optic chiasm
What is the epithalamus?
Includes (but not limited to) the pineal gland
Is the epithalamus paired?
Yes, except for the pineal gland
What does the pineal gland do?
Produces melatonin for sleeping
Why is the pineal gland radiopaque?
Contains calcium salts/pineal salts
Why is it useful that the pineal gland is radiopaque?
Is used as a landmark in X-rays
Where is the pineal gland?
Attached to the roof of the third ventricle
What are the three parts making up the brainstem?
Midbrain, pons and medulla
What 6 things make up the midbrain?
Cerebral peduncles, substantia nigra, red nucleus, cerebral aqueduct, superior cerebellar peduncle and the mamillary bodies
Where are the cerebral peduncles?
Are on the anterior of the midbrain
What do the cerebral peduncles do?
Connect the brain to the brainstem (fiber tracts)
Where are the colliculi?
Posterior side of the midbrain
What do the superior colliculi do?
Visual reflexes
What do the inferior colliculi do?
Auditory reflexes e.g. startle reflex
What are the 3 cerebellar peduncles?
The superior, middle and inferior cerebellar peduncles
Where is the substantia nigra?
Deep to the cerebral peduncles
Why is the substantia nigra dark?
Has melanin pigment as is a dopamine precursor
What does the substantia nigra do?
Produces dopamine for movement pathways, stops break in globus pallidus
What are the two parts of the substantia nigra?
Pars compacta (SNPc) and Pars reticulata (SNPr)
What is the SNPc?
Substantia nigra pars compacta, has compacted cell bodies and is more posterior
What is the SNPr?
Substantia nigra pars reticulata, has less compact cells and is more anterior
What does the SNPr connect to?
Thalamus, inhibitory to stop unwanted movements (therefore if neurons die get unwanted movements)
Where is the red nucleus?
Deep to substantia nigra in the midbrain
Why is the red nucleus red?
Rich blood supply and iron pigment
What does the red nucleus do?
Is a relay station for some descending motor pathways
Where are the mamillary bodies?
Behind the optic chiasm and pituitary gland, in the midbrain
What do the mamillary bodies do?
Relay information from the hypothalamus to the rest of the brain
What are two things associated with the pons?
4th ventricle and middle cerebellar peduncles
What is an example of a pontine nuclei?
Pneumotaxic center, controls breathing rhythm
What are 4 things making up the medullla?
Pyramids, olives, 4th ventricle and inferior cerebellar peduncles
Where are the pyramids?
Egypt
Anterior side of medulla
What are the pyramids?
The descending motor tracts (are pyramidal neurons hence pyramids)
What is pyramidal decussation?
Where the neurons cross sides, so motor control is contralateral
Where are the olives?
Lateral to the pyramids in medulla
What are the olives?
Nuclei for ascending sensory information
What are the fasciculus cuneatus and gracile?
Dorsal columns in the spinal cord
What does the fasciculus cuneatus control?
Upper limbs
Where is the fasciculus cuneatus?
Lateral superior dorsal columns
What does the fasciculus gracile control?
Lower limbs
Where is the fasciculus gracile?
Medial superior dorsal columns
What sulcus separates the fasciculus cuneatus and gracile?
Posterior intermediate sulcus
Why is there no fasciculus cuneate in the lower SC?
Because controls upper limbs so don’t need at the bottom
What role does the medulla have in homeostatic processes?
Has cardiovascular and respiratory centers that control HR, BP and breathing. Plus has other reflex centers e.g. gagging, vomiting swallowing etc.
What is the difference in grey and white matter between the brain and the SC?
Brain has grey matter on the outside, SC has grey matter in the inside
How many pairs of cranial nerves are there?
12
How many of the cranial nerves are associated with the brainstem?
10
How many of the cranial nerves are in the PNS?
11, the optic nerve is technically CNS
What are the 12 cranial nerves?
Olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory and hypoglossal
What is the acronym to remember the cranial nerves?
Oh Once One Takes The Anatomy Final Very Good Vacation A-Head
What is the acronym to remember whether the cranial nerves are sensory, motor or both?
Some Say Money Matters But My Brother Says Big Brains Matter Most
What is the first cranial nerve?
Olfactory
What bone do the olfactory nerves go through?
Cribriform plate of the ethmoid bone
Where do the olfactory nerves go after the cribriform plate?
Synapse onto the olfactory bulb and forms the olfactory tract and to the olfactory cortex
What parts of the brain does olfactory information go to?
Olfactory cortex in temporal lobe, hippocampus (memory), amygdala (emotions) and hypothalamus which projects to the reticular formation to produce autonomic responses (salivation)
What is the second cranial nerve?
Optic
Where does the optic nerve get through the skull?
The optic foramen
What is bitemporal hemianopia?
Can’t see periphery due to damage at optic chiasm
What does the visual association cortex do?
Processes more complex visual information
How does the frontal lobe use visual information?
To guide movements (plan)
What is the third cranial nerve?
Oculomotor
Where does the oculomotor nerve leave through the skull?
Superior orbital fissure
Where does the oculomotor nerve leave the brain?
From the anterior midbrain (by the cerebral peduncles)
What type of axons (motor/sensory) are in the oculomotor nerve?
Motor (some proprioception)
What does the oculomotor nerve do?
Controls eye muscles and autonomic pupil constriction and lens movements
Which muscles does the oculomotor nerve control?
Inferior oblique, superior, middle and inferior rectus muscles. Also does ciliary muscles and ones that control lens and eyelid
What happens when the oculomotor nerve is damaged?
Drooping eyelid, dilated pupil, can’t focus or move eyes in certain directions
What is the 4th cranial nerve?
Trochlear
Where does the trochlear nerve leave through the skull?
The superior orbital fissure
Where does the trochlear nerve leave the brainstem?
Posterior side of midbrain (only nerve to come from posterior side)
What type of axons (M/S) are in the trochlear nerve?
Motor (some proprioception)
What muscle does the trochlear nerve control?
The superior oblique muscle
What movement does the trochlear nerve allow?
Downwards and to the side
What happens if the trochlear nerve is damaged?
Cant move eye down and out (inferolateral) and double vision
What is the 5th cranial nerve?
Trigeminal
What are the 3 divisions of the trigeminal nerve?
V1 - Ophthalmic division
V2 - Maxillary division
V3 - Mandibular division
Where does the trigeminal nerve leave/come into the brain?
From the lateral side of the pons
Where does the V1/ophthalmic division go into the skull?
Superior orbital fissure
What does the ophthalmic division do?
Sensory information from the upper face, nasal cavity up
Where does V2/maxillary division enter the skull?
Foramen rotundum
What dos the maxillary division do?
Information from middle part of skull (nose and upper teeth)
Where does the V3/mandibular division enter/leave the skull?
Foramen ovale
What does the mandibular division do?
Sensory from lower teeth, anterior tongue and chin. Does motor to muscles of mastication (chewing)
Where do the cell bodies of the sensory neurons in the trigeminal nerve sit?
In the trigeminal ganglion
Is the trigeminal nerve motor or sensory?
Both, V1 and V2 primarily sensory but V3 is both
What happens if the trigeminal nerve is damaged?
Sensory loss in the face and impaired chewing
What is Tic Douloureux?
Inflammation in the trigeminal nerve creating intense pain with stimulation
How do you treat Tic Douloureux?
Analgesics only partially effective so can cut the trigeminal nerve
What is the 6th cranial nerve?
Abdeucens
Where does the abducens leave the brain?
Most medial one at the pons/medulla junction
Where does the abducens leave the skull?
Superior orbital fissure
What does the abducens nerve do?
Abduction of the eye
What muscle does the abducens act on?
Lateral rectus muscle
What happens if the abducens nerve is damaged?
Lazy eye as can’t move eye laterally
is the abducens nerve motor or sensory?
Motor
What is the 7th cranial nerve?
Facial
Where does the facial nerve leave the brain?
Pons and medulla junction lateral to the abducens
Where does the facial nerve leave the skull?
Internal auditory meatus
How many branches does the facial nerve have?
5, like a hand
What are the 5 branches of the facial nerve?
Temporal, Zygomatic, buccal, mandibular and cervical
What does the facial nerve do?
Facial expression muscles, and tastebuds from anterior 2/3rds of tongue as well as tears and salivary glands
What happens if the facial nerve is damaged?
Sagging face and no taste from front of tongue
Is the facial nerve sensory or motor?
Both
What is Bells Palsy?
Paralysis of face on one side due to viral infection of facial nerve on one side
What is the 8th cranial nerve?
Vestibulocochlear
Where does the vestibulocochlear nerve enter the skull?
Internal auditory meatus
Where does the vestibulocochlear nerve enter the brain?
Pons medulla junction, most lateral
Is the vestibulocochlear nerve sensory or motor?
Sensory
What does the vestibulocochlear nerve do?
Carries auditory and vestibular information
What happens if the vestibulocochlear nerve is damaged?
Deaf, dizzy and nystagmus (eyes moving involuntarily)
What is the 9th cranial nerve?
Glossopharyngeal
Where does the glossopharyngeal nerve leave the brain?
The lateral side of the medulla
Where does the glossopharyngeal nerve leave the skull?
The jugular foramen
What does the glossopharyngeal nerve do?
Control over swallowing, gagging, sensations from posterior 1/3 of tongue, salivation, BP and respiration
What happens if the glossopharyngeal nerve is damaged?
Can’t swallow and no taste from back of tongue
What is the 10th cranial nerve?
Vagus
Where does the vagus nerve leave the brain?
Lateral side of medulla below glossopharyngeal and more lateral then hypoglossal
Where does the vagus nerve leave the skull?
Jugular foramen
What does the vagus nerve do?
Vague as lots of functions, controls pharynx, larynx, heart, lungs and abdominal viscera plus more
What happens if the vagus nerve is damaged?
hoarseness/loss of voice, impaired swallowing and digestive motility. Is fatal if both are damaged
What is the 11th cranial nerve?
Accessory
What are the two roots of the accessory nerve?
Cranial and spinal root
Where does the cranial root of the accessory nerve leave the brain?
The lateral medulla below the vagus nerve
What does the cranial root of the accessory nerve do?
Joins the vagus nerve to supply motor axons in pharynx, larynx etc
What happens if the cranial root of the accessory nerve is damaged?
Hoarseness/loss of voice
Where does the cranial root of the accessory nerve leave the skull?
Jugular foramen
Where does the spinal root of the accessory nerve come from?
From the spinal nerves then travels up through the foramen magnum to join the cranial root
What does the spinal root of the accessory nerve do?
Provides motor axons to the neck muscles
Where does the spinal root of the accessory nerve leave the skull?
The jugular foramen with the cranial root
What happens if the spinal root of the accessory nerve is damaged?
Can’t move neck or shoulders
Is the accessory nerve motor or sensory?
Motor (some proprioception)
What is the 12th cranial nerve?
Hypoglossal
Where does the hypoglossal nerve leave the brain?
Between the pyramids and olives in the medulla (in front of vagus)
Where does the hypoglossal nerve leave the skull?
Hypoglossal canal
What does the hypoglossal nerve do?
Controls the tongue
What happens if the hypoglossal nerve is damaged?
Trouble with swallowing and speaking
What is the reticular formation?
Nuclei in the brainstem that regulate habituation and arousal of the brain
What is the main job of the cerebellum?
Coordination of movements across several joints, sends blueprint to motor cortex
What happens if the cerebellum is damaged?
Poor coordination
How does the cerebellum get sensory information?
The cerebellar peduncles
What are the grooves at the top and bottom of the cerebellum in the middle called?
Anterior and posterior cerebellar incisures
What dural fold lies in the posterior cerebellar incisure?
Falx cerebri
What is the worm thing running down the cerebellum?
The vermis
What are folia?
The lines running along the cerebellum, are grey matter
What does the white matter make in the cerebellum?
The arbor vitae
What cells do input to the cerebellum?
Mossy fibers and climbing fibres
What do mossy fibers do?
Convey motor and sensory input from the brainstem
What do climbing fibers do?
Convey proprioceptive information from the inferior olivary nuclei
What do the climbing fibers synapse onto?
One to one onto purkinje cells and has collateral synapsing onto the deep nuclei
What do the mossy fibers synapse onto?
Granule cells and has collaterals that synapse onto the deep nuclei
What is a parallel fiber?
The axon of a granule running parallel to the surface of the cerebellum to go and synapse onto cells
What do the granule cells synapse onto?
Purkinje cells
What do Purkinje cells synapse onto?
Deep nuclei
Are purkinje cells excitatory or inhibitory?
Inhibitory
Where does the information go after the deep nuclei of the cerebellum?
Sends blueprint to motor cortex
Where is the primary fissure?
Half way down the cerebellum, runs horizontally
What lobes does the primary fissure divide?
Anterior and posterior lobes
What makes up the flocculonodular lobe?
Two flocculi and the nodulus
What are on the side of the flocculi?
The paraflocculi
What is below the flocculonodular lobe?
The tonsils
What does the flocculonodular lobe do?
Balance
What can happen if the tonsils are inflamed?
Can press on the medulla and cause death
What are the 3 sagittal subdivisions of the cerebellum?
Median zone (vermis), intermediate zone and lateral zone
How is the cerebellum divided sagittally?
By which area projects to what deep nuclei
What are the deep nuclei in the cerebellum?
Fastigial nucleus, interposed nucleus made up of the globose and emboliform nucleus and lastly the dentate nucleus
Where does the median zone project to?
The fastigial nucleus
Where does the intermediate zone project to?
The interposed nucleus (globose and emboliform)
Where does the lateral zone project to?
The dentate nucleus
Where does the cerebrocerebellar circuit get input?
Motor info from the pontine nuclei and sensory info from the inferior olivary nucleus to lateral zone of cerebellum
Where does info in the cerebrocerebellar circuit go after the lateral zone?
Goes to dentate nucleus then motor area and motor output is sent out
What does the cerebrocerebellar tract do?
Controls multijointed limb movements
What does the spinocerebellar tract (lateral) do?
Controls accuracy of limb movement
What is the difference between the cerebrocerebellar and the lateral spinocerebellar tracts?
Cerebrocerebellar goes to the lateral zone and then dentate nucleus, the spinocerebellar goes to the intermediate zone and then the interpositus nucleus
What does the spinocerebellar tract (medial) do?
Controls posture by controlling axial muscles in the trunk
What inputs into the medial spinocerebellar tract?
Inferior olivary nucleus, no cortical input
What tract does the lateral spinocerebellar circuit use?
Lateral corticospinal tract
What tract does the medial spinocerebellar circuit use?
Ventral corticospinal tract
Where does the vestibulocerebellar circuit go?
To floccuonodular lobe via inferior cerebellar peduncles and then to medulla and then body
What does the vestibulocerebellar circuit do?
Balance
Does the vestibulocerebellar circuit involve the cerebrum?
No
What are ballistic movements?
Rapid movements, not enough time to think so based off learned motor programs
What happens if the cerebellum is damaged?
Ataxia, tremor, nystagmus, headache and vomiting
What does the discriminative pathway feel?
Concious perception of touch
WHere does the discriminitive path go?
UP dorsal column paths
What does the non-discrimitive path do?
Pain, temperature, deep pressure
Where does the non-discrimitive path go?
Up the spinothalamic pathway
Where does the dorsal path go?
From peripheruy synapses onn cunneate/gracile nuclei then up to thalamus crossing in meddula then syapses and goes to cortex
What os the dorsal path also called?
Medial leminiscus
Where does the spinothalamic path go?
From periphery to SC crosses over then up to thalamus then somatosensory cortex
Where does the spinothalamic path go up the dorsal columns?
Up the lateral tracts
Where does the spinocerebellar tract go (input)?
From periphery to dorsay horn and up to crebellum
How manu neurons in spinocerebellar tract input?
only 2 no 3rd order neuron
What side does the spinocerebellar tract go on?
Ipsilateral, no decussation so cerebellum controols same sude not contralateral
