Neuro Flashcards
What is the most posterior part of the corpus callosum called?
Splenium
What is the main mid portion of the corpus callosum called?
Body
What is the anterior portion of the corpus callosum called?
Genu
What is the most inferior part of the corpus callosum called?
Rostrum
What are the functions of the cerebellum?
1) Maintaenance of balance and posture
2) Coordination of voluntary movements
3) Motor learning
4) Some cognitive functions
What are the lobes of the cerebellum?
1) Anterior lobe
2) Posterior lobe
3) Flocculonodular lobe
What divides the anterior and posterior lobes of the cerebellum?
Primary fissure
What divides the Floculonodular lobe from the posterior lobe?
Posterolateral fissure
What is the largest of the deep nuclei in the cerebellum?
Dentate nucleus
What is the most medial of the deep cerebellar nuclei?
Fastigial nucleus
What nuclei is situated just lateral to the fastigial nucleus?
Interposed nuclei
What nuclei is considered functionally analogous to the cerebellar nuclei but is not situated in the cerebellum?
Vestibular nuclei
What passes through the inferior cerebellar peduncle?
Primary afferent fibers from the medulla as well as efferents from the vestibular nuclei
What passes through the middle cerebellar peduncle?
Afferents from the pontine nuclei
What passes through the superior cerebellar peduncle?
Efferent fibres from the cerebellar nuclei and efferents from the spinocerebellar tract
What is the vestibulocerebellum?
It comprises of the flocculonodular lobe and connects with the lateral vestibular nuclei
What is the spinocerebellum?
Comprises of the vermis and intermediate zones as well as the fastigial and interposed nuclei
What is the cerebrocerebellum?
Comprises of the lateral hemispheres and the dendate nucleus
What do the granule cells receive input from?
Mossy fibers
What doe the granule cells project to?
Purkinje cells
Where do the mossy fibres originate?
Pontine nuclei, spinal cord, reticular formation and the vestibular nuclei
Each mossy fibre innervates one granule cell. True or false?
False - they innervate hundreds
What fibres do the granule cells form?
Parallel fibres
Where do climbing fibres originate?
Inferior olive
What do the mossy fibres project onto?
1) Granule cells
2) Cerebellar nuclei
What do the climbing fibres project to?
1) Cerebellar nuclei
2) Purkinje cells
Each purkinje fibre receives a single input form a single climbing fibre. True or false?
True - it is a single, very powerful input
What can happen if the cerebellum is damaged?
1) Deposition of movement
2) Intention tremor
3) Deficits in motor learning
What is the role of the mossy fibers?
Convey sensory information which is used to evaluate the sensory context of the movement
What is the role of the climbing fibres?
Convey error signals - thus they play a role in motor learning, making corrections
Where is CSF reabsorbed?
Superior sagittal sinus
Where are the venous sinuses located?
Between the meningeal and endosteal dural layers
Does the cavernous sinus receive blood from the orbit?
Yes
Where does the straight sinus receive blood from?
Inferior sagittal sinus and great cerebral vein
What vein do the dural venous sinuses drain into?
Internal jugular vein
Where does the majority of the blood supply to the brain come from?
Internal carotids
The left anterior cerebral artery carries blood to the motor cortex of the left leg. True or false?
False - it carries blood to the motor cortex of the right leg, the motor cortex controls the contralateral side of the body
What arteries carry blood to the basal ganglia?
Lenticulo-striate arteries
What is the cerebellum’s arterial blood supply?
1) Superior cerebellar artery
2) Anterior inferior cerebellar artery
3) Posterior inferior cerebellar artery
The middle cerebral artery is a direct continuation of the internal carotid artery. True or false?
True
The circle of willis is an uncommon site for berry aneurysms. True or false?
False - it is common
The communicating arteries in the Circle of Willis are functional anastomes between the right and left circulations. True or false?
False - Anterior is a physical link but not functional, posterior is to same side
In what lobe is Broca’s area located?
Frontal
In what area is Wernicke’s area located?
Temporal
A stroke to the temporal lobe will affect memory problems. True of false?
True
A stroke affecting the occipital lobe will result in?
Contralateral homonymous hemianopia
A stroke affecting the internal capsule is usually embolic. True or false?
False - they are haemorrhagic of the lenticostriate artery
A stroke affecting one side of the motor or somatosensory cortex would result in contralateral deficit. True or false?
True - sensory and motor control is carried out by the contralateral side of the brain
A right hemisphere stroke is likely to cause dyshasia in a left-handed individual. True or false?
False - majority of left-handed individuals are left-sided dominant as well so speech and language would be controlled on the left side
What gyrus does the primary motor cortex occupy?
Pre-central gyrus
The primary motor cortex is supplied by the middle cerebral artery only. True or false?
False - it is supplied by the ACA as well
The largest muscles of the body are given the largest area of the motor cortex. True or false?
False - the area of the motor cortex given to parts of the body depends on how richly innervated the area is
What is the Brodman’s area for the primary motor cortex is what?
4
Muscles of the lower limbs are represented medially in the motor cortex and upper limbs laterally. True or false?
True - the top medial part of the motor homolucus is the bottom of the body, moving medially and inferiorly it innervates higher up the body
Where does the corticospinal tract originate from?
The motor cortex
The corticospinal tract passes between the basal ganglia and the thalamus to enter the cerebral peduncle. True or false?
True - it passes in the internal capsule
The lateral corticospinal tract decussates at the pons. True or false?
False - it decussates at the medulla
What would happen if there was a lesion above the medullary pyramids?
There would be contralateral deficit
A stroke of the motor cortex will have a greater neurological deficit than the same size stroke of the internal capsule. True or false?
False - it would be lesser
In Parkinson’s disease there is an abnormal rhythmical output of the motor cortex. True or false?
False - the abnormal rhythmical output is from the basal ganglia
Upper motor neurones innervate the muscles directly. True or false?
False - they are innervated by the lower motor neurones
The axons of the upper motor neurones are located in the lateral white matter of the spinal cord. True or false?
True
The cell bodies of the lower motor neurones are located in the lateral horn of the spinal cord. True or false?
False - they are located in the ventral horn as the UMN cross lateral to ventral at the appropriate spinal level
A motor unit is defined as a particular muscle and all the motor neurones that innervate it. True or false?
False - a motor unit is a motor neurone and all the muscle fibres it innervates
Lower motor neurones leave the spinal cord posteriorly. Ture or false?
False - they leave ventrally (Anteriorly)
The lateral corticospnal tract is entirely uncrossed. True or false?
False - It decussates at the medullary pyramids. The anterior CST is uncrossed
What tract carries fibres to the muscles involved in balance and posture?
Vestibulospinal
What is the function of the corticospinal tract?
Controls muscles of fine movement
The anterior corticospinal tract mainly supplies the side contralateral to the originating brain hemisphere. True or false?
True
The anterior corticospina; tract is located antero-lateral to the anterior horn of the grey matter. True or false?
False - it is located medially
The lateral corticospinal tract contains less fibres than the anterior corticospinal tract. True or false?
False - Lateral = 85%, anterior = 15%
What is the function of the tectospinal tract?
Turning of the head in response to visual stimulus
What is the origin of the tectospinal tract?
Superior colliculus
What is the function of the vestibulospinal tract?
It is involved in maintaining balance and posture
Does the vestibulospinal tract cross?
No
Where does the reticulospinal tract originate?
Pons and medulla
What is the function of the reticulospinal tract?
Facilitates or inhibits the activity of descending tracts
Waht si the function of the rubrospinal tract?
Believed to be fine control of movements of the hand
Does the rubrospinal tract cross?
Yes
Is the rubrospinal tract more or less skilled than the lateral corticospinal tract?
Less skilled
Where does the rubrospinal tract originate?
Red nucleus
The reticulospinal tract provides a pathway for the hypothalamus to control the autonomic spinal outflow. True or false?
True
What type of fibre are muscle spindles formed of?
Intrafusal
What type of muscle fibre is normal skeletal muscle composed of?
Extrafusal
The middle third of the muscle spindle is associated with type 1a efferent sensory nerves. True or false?
False - afferent
The two ends of the muscle spindle are contractile. True or false?
True
What type of motor neurones innervate the muscle fibres of the muscle spindle?
Gamma motor neurones
What type of motor neurones innervate the skeletal muscle fibres?
Alpha motor neurones
Gamma motor neurones innervate extrafusal fibres. True or false?
False - they innervate intrafusal fibres, the fibres of the muscle spindle
Muscles spindles can detect both contraction and relaxation. True or false?
True
Muscle spindle activity contributes to the change in muscle resistance to stretch following a stroke. True or false?
True
The startle reflex is an example of the stretch reflex. True or false?
False
The patellar, jaw, bicep and ankle reflexes are an example of what type of reflex?
Stretch
Muscle spindles detect a change in muscle tension. True or false?
False - They detect change in length
Muscles spindles are involved in both conscious and reflex proprioception. True or false?
True
Where are golgi tendon organs located?
Junction of skeletal muscle and tendon
What are the afferent nerve fibres from the golgi tendon organ?
Type 1b to anterior horn
The golgi tendon organ’s measure the force developed by a muscle and any resultant change in length. True or false?
False - they detect the force but not the change in length
Afferent impulses of the golgi tendon organ inhibits alpha motor neurones of the muscle in which the golgi tendon organ was activated in. True or false?
True - it works to regulate the muscle tension and keep it within a normal range
The golgi tendon organ’s are only inhibitors of skeletal alpha motor neurones. True or false?
False - they excite alpha motor neurones too
Golgi tendon organ output is proportional to the muscle tension. True or false?
True
Are the golgi tendon organs involved in the clasp knife reflex?
Yes
The golgi tendon organ’s contain muscle fibres to alter tension. True or false?
False - they only meausre
Golgi tendon organ’s possess faster afferent fibres than muscle spindles. True or false?
False - they are slower
Golgi tendon organ activity inhibits the inhibition of the antagonist muscles to which the one they were activated in. True or false?
False - they inhibit the same muscle (agonist)
The receptive fields in areas like the fingers are small. True or false?
True
Some cutaneous receptors are phasic in response while others are tonic. True or false?
True
Tactile receptors act as transducers but do not show summation. True or false?
False - they show temporal and spatial summation
Skin receptors are specialized neurone cell bodies. True or false?
False - the cell bodies lie in the dorsal root ganglion, the receptors are specialized ends of neurones
Is the conduction through the DCML slow or fast?
Fast
What sensations are carried by the DCML?
1) Fine touch
2) Two point discrimination
3) Vibration
4) Proprioception
The DCML lies in the anterior white matter of the spinal cord. True or false?
False - it lies in the dorsal
Fibres in the DCML are arranged topographically. True or false?
True
Where does the decussation of the DCML occur?
Medulla
When the plasma membrane of a neurone is at a resting potential there are more Na+ channels open than K+ channels. True or false?
False - other way round
The resting potential is positive inside the neurone compared to the outside. True or false?
False - it is negative inside the cell
What is the resting potential of the plasma membrane of a neurone?
-70mV
The resting potential of the neurone membrane is governed by the permeability of the membrane to sodium ions. True or false?
False - it is governed by its permeability to potassium
The resting potential is mostly the result of sodium diffusing out of the cell. True or false?
False - potassium
The size of the action potential depends on the threshold reached. True or false?
False - it is all or nothing, the action potential only occurs if the threshold has been reached
Which channels open in the repolarisation of the plasma membrane?
Voltage-gated potassium channels
What is the change in membrane potential in an action potential?
-70mV to +30mV
At +30mV the voltage-gated sodium channels close in response to the changed membrane potential. True or false?
False - they close after a particular length of time
What is the relative refractory period?
The period of time in which a second stimulus needs to be stronger to produce a second action potential
What is the length of the relative refractory period?
5-10ms
The relative refractory period is followed by an absolute refractory period. True or false?
False - the absolute refractory period precedes the relative
The majority of synapses are electrical true or false?
False - the majority are chemical
Chemical synapses are always inhibitory. True or false?
False - they are excitatory too
The refractory period has no effect on the frequency of the action potential capable of being produced. True or false?
False - It has an effect
A synaptic cleft is a feature of all synpases. True or false?
False - only chemical, electrical have gap junctions
Synapses are the site of all neurotransmitter synthesis. True or false?
False - the majority is synthesized in the cell body
Each synpase can only form one synpase with another neurone. True or false?
False - they often form many
The closing of calcium channels are responsible for the release of neurotransmitters. True or false?
False - the opening is responsible
Damage to the Olfactory nerve results in anosmia of the contralateral side. True or false?
False - ipsilateral
CN I is commonly damaged in fractures to the anterior cranial fossa. True or false?
True
Damage to CN I can leads to loss of sensation to the nasal septum. True or false?
False - Sensation provided by opthalmic nerve V1
CN II first joins the opposite nerve at the optic radiation. True or false?
False - it meets at the optic chiasm
CN II’s fibres go to the medial geniculate body. True or false?
False - they go the the lateral
Total blindness of the left eye would occur in a lesion to what?
Left optic nerve
What passes through the cavernous sinus?
CN III, CN IV, CN V1 and V2, CN VI and internal carotid
What is the parasympathetic nucleus of CN III?
Edinger-Westphal nucleus
What does the parasympathetic innervation from CN III do?
Accommodation and pupil constriction
Damage to the CN III will lead to ptosis of the eyelid n the opposite side. True or false?
False - same side
Damage to CN VI will lead to the inability to what?
Abduct the eye
A person with damage to CN IV will complain of double vision when looking up. True or false?
False - when looking down
Damaged to CN V will lead to loss of control of the corneal reflex on the effected side. True or false?
True - It is innervated by V1 - nasocillary branch and VII - temporal and zygomatic branches
What is the innervation of the submandibular gland?
Facial nerve
What is the innervation of the sublingual gland?
Facial
What is the innervation of the parotid gland?
Glossopharyngeal
An UMN lesion of CN VII result in drooping of the eyelid. True or false?
False - Forehead muscles are not affected in UMN lesions but are in LMN lesions
CN VII has its nucleus in the tectum of the pons. True or false?
False - Tegmentum (ventral usually motor as in the spinal cord)
When CN VIII is diseased it can cause rapid eye movements; nystagmus. True or false?
True
Damage to CN VIII would lead to tuning fork on forehead being best heard in the opposite ear. True or false?
True
CN X leaves the brain at the level of the pons. True or false?
False - Medulla between pyramid and inferior cerebellar peduncle
What innervates the stylopharyngeus muscle?
CN IX
CN X increases heart rate and blood pressure when stimulated. True or false?
False - decreased
CN XI has a single root. True or false?
False - cranial and spinal
CN XI runs in close proximity to the vertebral artery. True or false?
False - Internal jugular vein, they exit skull together
Injury of CN XI causes paralysis of sternocleidomastoid and superior trapezius muscle on opposite side. True or false?
False - same side
CN XII only supplies the intrinsic muscles of the tongue. True or false?
False - Majority of extrinsic and all of intrinsic
CN XII has its nerve cell bodies in the medulla. True or false?
True
Damage to CN XII causes paralyisis of the ipsilateral side of the tongue. True of false?
True
The spinothalamic tract is found in the dorsomedial white matter of the spinal cord. True or false?
False - anterolateral
After they decussate the fibres of the spinothalamic tract project directly to the neocortex. True or false?
False - they synapse at the thalamus first
Hemisection of spinal cord at C7 on right would lead to loss of two-point discrimination on the left. True or false?
False - Right, DCML decussates at the medulla
Hemisection of spinal cord at C7 on right would lead to right sided hemiparesis. True or false?
False - Hemiplegia
Hemiparesis is weakness on one side, hemiplegia is paralysis on one side
Hemisection of spinal spinal cord at C7 on right would lead to LMN paralysis at level of C7 on ispsilateral side. True or false?
True - severed CST
The middle ear is a fluid-filled chamber that communicates with the nasal cavity. True or false?
False - it is filled with air (pressure equilisation - Valsalva)
The round window receives sound waves in the ear. True or false?
False - the oval window
Sensation to the middle ear is via CN VIII. True or false?
False - Glossopharyngeal
The chain of ossciles in the ear have cartilaginous joints between them. True or false?
False - synovial
The stiffness of the ossicular chain can be altered by two muscles, what are they?
Tensor tympani
Stapedius
The scala vestibule is continuous with the scala tympani via the semicircular canals. True or false?
False - via helicotrema
the Organ of Corti is a specialised structure that rests on the basilar membrane. True or false?
True - contains auditory cells
How many times does the cochlear coil aound its modiolus?
2.5 times
The basilar membrane is narrower at its apex and wider at its base. True or false?
False - other way round
The base of the basilar membrane is sensitive to low frequencies whereas the apex is sensitive to high frequencies. True or false?
False - other way round
The outer hair cells are are 4-5 rows while the inner hair cells are just one row. True or false?
True
During ageing high tone deafness occurs first. True or false?
True
The semi-circular canals detect the position of the head with respect to gravity and linear rotation. True or false?
False - they detect rotational acceleration and deacceleration
Damage of the semi-circular canals on one side will result in nystagmus with the slow phase towards damaged side and rapid away. True or false?
True
Semi-circular canals in the left ear affect both ears. True or false?
True
Pouring ice cold water in the external auditory meatus can cause convection currents in the semicircular canals and systagmus. True or false?
True
The utricle and saccule signal the position of the head to gravity and rotational acceleration. True or false?
False - it is linear rotation
Basilar membrane is in the cochlea and separates the fluid-filled scala media and scala tympani. True or false?
True
The utricle and sacule are filled with lymph. True or false?
False - Endolymph
Mossy fibres are dervived from the inferior olivary nucleus. True or false?
False - various brainstem nuclei
Climbing fibres are involved in learning new motor actions. True or false?
True
Mossy fibres are believed to be involved in motor programme determination. True or false?
True
The output neurones from the cerebellar cortex are called granule cells and are excitatory. True or false?
False- they are called Purkinje fibres and are inhibitory
Each purkinje fibre receives input from thousands of parallel fibres. True or false?
True - error signally processing
Feedback information from the cerebellum to the cerebral cortex travels via the medial and lateral geniculate bodies. True or false?
False - travels via the ventrolateral thalmus
The cerebellum is involved in the initiation of co-ordinated movement. True or false?
False - this is done by the basal ganglia, cerebellum compares intended with actual and adjusts
The cerebellum is believed to play a role in the storage and learning of motor skills. True or false?
True
The cerebellum receives information primarily from the vestibular system. True or false?
True - co-ordination, posture and balance are key
The cerebellum is not a part of a direct pathway to nystagmus. True or false?
True - but vestibulocerebellum lesions can lead to nystagmus
A lesion of the left lobe of the cerebellum will lead to decomposition of movement on the left side of the body?
True - ipsilateral control
Olfaction and gustation are represented ipsilaterally in post-central gyrus and insular cortex. True or false?
True
Afferents from the olfactory receptors directly project to the primary gustatory cortex. True or false?
False - They synapse with the mitral cells in the olfactory bulb
A single glomerulus in the olfactory bulb takes input from many receptors corresponding to a specific part of the nasal lining. True or false?
False - they each have the same odour sensitivity
Taste sensation is carried out by CN VII, IX and X. True or false?
True
What are the pyramidal tracts?
1) Corticospinal
2) Corticobulbar
What is the function of the corticospinal tracts?
Supplies the musculature of the body
What is the function of the corticobulbar tracts?
Supplies the musculature of the head and neck
Where does the corticospinal tract originate?
Cerebral cortex - receives inputs from primary motor, premotor, supplementary motor cortex’s and somatosensory areas
The corticospinal tract splits into two. What does it split into and where?
1) Lateral corticospinal tract - decussates
2) Anterior corticospinal tract - decussates just before it terminates in the ventral horn of cervical and upper thoracic segments
Where does the corticobulbar tracts originate?
Lateral aspect of the motor cortex
Where do the neurones of the corticobulbar tracts terminate?
On the motor nuclei of the cranial nerves
Many of the motor neurones are innervated by the corticobulbar tract unilaterally. True or false?
False - Bilaterally
What are the extrapyramidal tracts?
1) Vestibulospinal
2) Reticulospinal
3) tectospinal
4) Rubrospinal
Which of the extrapyramidal tracts decussate?
1) Ruprospinal
2) Tectospinal
Which of the extrapyramidal tracts do not decussate?
1) Rectospinal
2) Vestibulospina;
Where does the vestibulospinal tract originate?
Vestibular nuclei
What is the function of the vestibulospinal tract?
It controls balance and posture by innervating the “anti-gravity” muscles
Where does the rectospinal tracts originate?
1) Medial - Pons
2) Lateral - Medulla
What is the role of the medial reticulospinal tract?
Facilitates voluntary movement
What is the role of the lateral reticulospinal tract?
Inhibits voluntary movements and reduces muscle tone
Where does the rubrospinal tracts originate?
Red nucleus
What is the function of the rubrospinal tract?
Believed to play role in fine control of hand
Where does the tectospinal tract originate?
Superior colliculus
What is the function of the tectospinal tracts?
Control head turing in response to visual stimuli
What is hypertonia?
Increased muscle tone
What is hyperreflexia?
Increased muscle reflexes
What is clonus?
Involuntary, rhythmic muscle contractions
What is the bambinski sign?
Extension of the big toe in response to blunt stimulation of the sole of the foot
What is the action of the lateral rectus?
Abduction of the eye
What is the action of the medial rectus?
Adduction of the eye
What is the action of the superior rectus?
Upward movement of the eye
What is the action of the inferior rectus?
Downwards movement of the eye
What is the action of the superior oblique?
Intorsion and downwards movement
What is the action of the inferior oblique
Extorsion and upwards movement
What is the innervation of the lateral rectus?
Abducens - CN VI
What is the innervation of the superior oblique?
Trochlear - CN IV
What is the Lentiform nucleus comprised of?
1) Putamen
2) Globus pallidus
What is the anterior of the Lentiform nucleus continuous with?
Caudate nucleus
What can be seen in a coronal section of the brain that constitutes the Lentiform nucleus?
1) Putamen - Lateral
2) Intermediate - external globus pallidus
3) Medial - Internal globus pallidus
What is the Lentiform nucleus part of?
Basal ganglia
What structures make up the basal ganglia?
1) Dorsum striatum
2) Ventral striatum
3) Globus pallidus
4) Ventral pallidum
5) Substantia nigra
6) Subthalamic nucleus
What is the dorsal striatum made up of?
1) Caudate nucleus
2) Putamen
What is the ventral striatum made up of?
1) Nucleus accumbens
2) Olfactory tubercle
The inner ear is composed of two main components, what are they?
1) Bony labyrinth
2) Membranous labyrinth
What does the bony labyrinth contain?
1) Cochlea
2) Vestibule
3) Three semi-circular canals
What lines the structures of the bony labyrinth?
Periosteum
What fills the structures of the bony labyrinth?
Perilymph
What structures does the membranous labyrinth contain?
1) Cochlear duct
2) Semicircular ducts
3) Utricle
4) Saccule
What fills the structures in the membranous labyrinth?
Endolymph
Where does the oval window lie?
Between the middle ear and the vestibule
What does the round window separate?
Middle ear and scala tympani (part of the cochlear duct)
Where is the bony labyrinth located?
Petrous part of the temporal bone
What is located within the vestibule?
1) Saccule
2) Utricle
What does the vestibule communivate with?
Cochlear - anteriorly
Semi-circular canals - posteriorly
What lies inside of the cochlea?
Cochlea duct
What is the name of the central portion of the cochlea?
Modiolus
What nerve is found at the base of the modiolus?
Cochlea portion of the vestibulocochlear nerve
What is the Scala vestibuli?
A perilymph-filled chamber superior to the cochlear duct - it is continuoous with the vestibule
What is the Scala tympani?
A perilymph-filled chamber inferior to the cochlear duct - it terminates at the round window
What are the three semi-circular canals?
1) Anterior
2) Lateral
3) Posterior
What is contained within the semi-circular canals?
Semi-circular ducts
What holds the cochlear duct in place?
Spiral lamina
What does the utricle receive?
The three semicicular ducts
What does the saccule receive?
Cochlear duct
What blood vessel is the membranous labyrinth supplied by?
Labyrinthine artery
What is the function of the basal ganglia?
It is involved in the selection of co-ordinated movement
What is the limbic system comprised of?
1) Olfactory bulbs
2) Hippocampus
3) Hypothalamus
4) Amygdala
5) anterior thalamic nuclei
6) Fornix
7) Septum pellucidum
8) Cingulate gyrus
9) Parahippocampal gyrus
10) Limbic cortex
What is the function of the limbic system?
It is involved in emotion, behaviour, motivation, long-term memory and olfaction
