Question 1

What 4 things make up the basal ganglia?

Accepted Answer

striatum, globus pallidus, substantia niagra, subthalamic nucleus

Question 2

Describe the feedback circuits in the basal ganglia?

Accepted Answer

Motor cortex stimulates Striatum -- Indirect path or direct path. Indirect path - neostriatum - inhibits EGP which inhibits IGP or the subthalamic nuclei -both go to IGP (subthal has + effect on it IGp. IGP is uninhibited as EGP is inhibited. So it is not directly inhibiting it or indirectly inhibiting it through the subthalamic nuclei and so overall IGP is uinihibited. IGP normally inhibits the Thalamus) So the Thalamus is inhibited and cannot stimulate the frontal lobe. direct pathway: striatum -- inhibits IGP pars reticulata complex -- which usually inhibits thalamus -- therefore allows the thalamus to stimulate the motor cortex. Direct pathway stimulates the motor cortex, indirect inhibits it.

Question 3

How does the substantia niagra pars compacta act?

Accepted Answer

It increases activity of direct pathway via D1 receptors while suppressing the indirect with D2 receptors.

Question 4

What is dysmetria?

Accepted Answer

type of ataxia - undershoot (hypometria) or overshoot (hypermetria) an intended position.

Question 5

where does spinal cord terminate at birth and in adult?

Accepted Answer

``` birth = L3 Adult = L1/L2 ```

Question 6

How many spinal nerves are there?

Accepted Answer

31

Question 7

at what level do arachnoid and dural sheaths terminate? how does the pia end? Describe what happens to the layers as the nerves leave the spinal cord?

Accepted Answer

S2 and ends as filum terminale. As spinal nerve roots pass through intervertebral foramina they evaginate the arachnoid and dura forming meningeal root sleeves that extend as far as fusion of dorsal and ventral roots. Afterwards the 2 layers become continuous with the epineurium.

Question 8

In what tract do afferents enter and then ascend and descend a few segments before entering into grey matter?

Accepted Answer

Dorsolateral fasciculus (Lissauers tract)

Question 9

What is the substantia gelatinosa?

Accepted Answer

The tip of the dorsal horn, approximating to rexed lamina 1-3. It recieves collaterals of group A delta and group C afferents associated with nociception.

Question 10

what 2 NT do the neurones of the substantia gelatinosa use?

Accepted Answer

substance P and glutamate

Question 11

What is at lamina 7 and level C8-L3 the origin of ascending fibres of dorsal spinocerebellar tract?

Accepted Answer

Clarkes column

Question 12

In what rexed lamina are motor neurones that innervate skeletal muscle found? How many rexed lamina segments is the gray matter divided into?

Accepted Answer

Lamina 9. It is divided into 10 rexed lamina segments.

Question 13

Describe the dorsal columns?

Accepted Answer

Fasciculus gracilis (medial) recieves afferents from lower limb, sacral, lumbar and lower thoracic. Fasciculus cuneatus (lateral) recieves afferent neuron fibres from upper limb - cervical and upper thoracic. They ascend in columns on same side they entered - terminate in nucleus gracilis and nucleus cuneatus in the medulla - 2nd order then decussate in the medulla as internal arcuate fibers which then ascend through the brainstem in the medial lemniscus which terminates in the ventral posterior nucleus in the thalamus - 3rd order then go to somatosensory cortex.

Question 14

What info do dorsal columns carry?

Accepted Answer

proprioception and discriminative (fine) touch and vibration.

Question 15

Name 2 lesions of the dorsal columns?

Accepted Answer

Tabes dorsalis - late manifestation of syphilitic infection - high steppage and unsteady gait (sensory ataxia). Subacute combined degeneration - deficiency of vit B12 - sensory ataxia.

Question 16

Describe the pathway of the spinothalamic tract?

Accepted Answer

1st order - 2nd order cell bodies in dorsal horn - cross over to opposite side by passing through the ventral white commissure - In brainstem fibers run in close proximity to medial leminiscus in what is known as the spinal lemniscus - terminate in ventral posterior nucleus of the thalamus - 3rd order to somatosensory cortex

Question 17

What sensations does the spinothalamic tract carry? Name a spinothalamic lesion?

Accepted Answer

pain, temp and non disciminative (coarse) touch. Syringomyelia - central canal is enlarged - compresses and damages 2 order as cross in ventral white commissure.

Question 18

what sensations does the spinoreticular tract carry?

Accepted Answer

Dull aching slow pain

Question 19

describe the pathway of the spinoreticular tract?

Accepted Answer

1st order-- 2nd order arising from dorsal horn -- decusate and ascend on contralateral side (ascend in ventrolateral region of the cord) they terminate in the brain stem reticular formation -- reticulothalamic fibers ascend to intralaminar thalamic nuclei-- activate cerebral cortex

Question 20

What info does the spinocerebellar tract carry?

Accepted Answer

info from muscle spindles, GTOs and tactile receptors

Question 21

Describe the pathway of the dorsal spinocerebellar tract?

Accepted Answer

originates from group of cells called clarkes column - axons ascend ipsilaterally to cerebellum through inferior cerebellar peduncle

Question 22

Describe the path of the ventral spinocerebellar tract?

Accepted Answer

ascends on contralateral side enters cerebellum via superior cerebellar peduncle - some axons recross within the cerebellar white matter.

Question 23

Name a disease of the spinocerebellar tracts?

Accepted Answer

Friedreichs ataxia -inherited degenerative disease - intention tremor wide reeling gait. begins in childhood in a wheelchair by 20.

Question 24

describe the path of the corticospinal tract?

Accepted Answer

Cells bodies in cortex (Betz cells) --corona radiata and internal capsule --crus cerebri of midbrain --ventral pons -- form 2 prominent columns on ventral surface -- pyramids - in medulla fibres undergo subtotal decussation --75-90% decussate and enter the contralateral Lateral corticospinal tract --10-25% of fibres remain ipsilateral and enter the ventral corticospinal tract --which decussates near termination

Question 25

What is the name of the condition where degeneration of the lateral corticospinal tract takes place?

Accepted Answer

Hereditary spastic paraparesis - leads to spastic paraparesis with hyperreflexia.

Question 26

Describe the pathway of the rubrospinal tract?

Accepted Answer

red nucleus in midbrain tegmentum --axons leave ventromedially and cross in ventral tegmental decussation -- lie in ventrolateral and part mingled with Lat corticospinal -- exert control over tone of limb flexors

Question 27

Describe the pathway of the tectospinal tract?

Accepted Answer

Arise from superior colliculus of midbrain -- axons cross ventromedially around PAG and cross in dorsal tegemental decussation - lie near ventral median fissure -- terminate mainly in cervical segments.

Question 28

Describe the pathway of the vesticulospinal tract?

Accepted Answer

vestibular nuclei in pons and medulla -- Lat vestibular nucleus (deiter's nucleus) -- axons descend ipsilaterally as LAT vestibulospinal tract -- located in ventral funiculus -- controls extensor muscle tone to maintain antigravity posture.

Question 29

describe the reticulospinal tracts?

Accepted Answer

reticular formation of pons and medulla -- axons from pontine reticular formation descend ipsilaterally as medial ( or pontine) reticulospinal tracts. Axons from medulla descend bilaterally in lateral reticulospinal tracts. influence reflex activity and muscle tone by acting on alpha and gamma motor neurones.

Question 30

Describe features of an upper cervical cord lesion?

Accepted Answer

spastic tetraplegia (or quadraplegia), hyperreflexia, extensor plantar responses (UMN), incontinence, sensory loss below lesion and sensory ataxia.

Question 31

describe features of lower cervical cord lesion?

Accepted Answer

areflexia of upper limbs (LMN), spastic paraparesis, hyperreflexia and extensor plantar responses (UMN lesion) in lower limbs, incontinence, sensory loss below level of lesion and sensory ataxia.

Question 32

describe the features of a thoracic cord lesion?

Accepted Answer

spastic paraparesis, hyperreflexia, extensor plantar responses(UMN) incontinence, sensory loss below level of lesion and sensory ataxia

Question 33

describe features of lumbar cord lesion?

Accepted Answer

weakness, wasting and fasciculation of muscles. areflexia of lower limbs (LMN) incontinence, sensory loss below level of lesion, sensory ataxia.

Question 34

describe the features of brown sequard syndrome?

Accepted Answer

ipsilateral loss of proprioception and UMN signs (hemiplegia/monoplegia), contralateral loss of pain and temp sensation.

Question 35

What is a benign tumour of cranial nerve 8 called? what does it do?

Accepted Answer

acoustic neuroma, compresses structures on cerebellopontine angle. Lose corneal reflex first (V). Then 7 and 8 CN. The rest of V and sometimes IX and X. Get deafness, tinnitus and vertigo. Bilateral acoustic neuroma occurs in neurofibromatosis-type 2. DD: meningiomas, epidermoids, arachnoid cysts. Lower cranial nerve meningiomas.

Question 36

describe Bells palsy?

Accepted Answer

acute unilateral inflammatory lesion of facial nerve within its course through skull. Its LMN if cant wrinkle forehead, UMN - if can wrinkle forehead (unless bilateral lesion) symptoms: pain around ear, paralysis of facial muscles unilaterally, absent corneal reflex, hyperacusis (over sensitivity of frequency and volumes of sound), loss of taste sensation on anterior 2/3 of tongue. It is a LMN lesion. If can wrinkle head UMN which could be a stroke. SO IMPORTANT TO MAKE SURE IT IS DEFINITELY A LMN LESION I.E BELLS PALSY.

Question 37

What is bells palsy called when there is a rash in external auditory canal and mucus membrane of oropharynx ?

Accepted Answer

Ramsay Hunt syndrome - due to herpes zoster virus being present

Question 38

What is the convoluted surface of the cerebellum called? on the superior surface what fissure separates the anterior lobe from the larger posterior lobe?

Accepted Answer

folia deep primary fissure

Question 39

how many lobes are their in the cerebellum? and how many smaller lobules?

Accepted Answer

3 lobes - anterior, post, and flocculonodular lobess 10 smaller lobules

Question 40

What is the white matter in the cerebellar called? how many cerebellar nuclei are there?

Accepted Answer

arbor vitae, 4 cerebellar nuclei

Question 41

what are the 3 layers of the cerebellar cortex?

Accepted Answer

outer fibre rich layer = molecular layer, intermediate = purkinje cell layer, inner = granular layer

Question 42

How do fibres enter cerebellum and proceed to the cortex?

Accepted Answer

via mossy fibres - end in granular layer or climbing fibres - input to purkinje cells

Question 43

Name 4 cerebellar nuclei?

Accepted Answer

Fastigial nucleus, Globose nucleus, emboliform nucleus, dentate nucleus.

Question 44

Name the 3 functional areas of the cerebellum? describe each?

Accepted Answer

Archicerebellum - oldest part - mainly concerned with balance - is the flocculonodular lobe and associated fastigial nuclei. Paleocerebellum - muscle tone and posture - midline vermis and surrounding paravermis and globose and emboliform nuclei Neocerebellum - mucule coordination - remainder (most) of cerebellar hemisphere and dentate nuclei.

Question 45

Name 4 features of a cerebellar lesion?

Accepted Answer

intention tremor, cerebellar ataxia, dysarthria a motor speech disorder (ask to repeat 'baby hippopotamus') and nystagmus. DANISHP.

Question 46

what is myoclonus?

Accepted Answer

sudden shock like movements usually affecting upper limbs

Question 47

What are dystonias?

Accepted Answer

sustained muscular contractions that give rise to abnormal postures or contortions.

Question 48

what is athetosis?

Accepted Answer

slow involuntary writhing sinous complicated movement of fingers, hands, toes, feets, arm, legs, neck, tongue

Question 49

What is hepatolenticular degeneration?

Accepted Answer

Occurs in Wilsons disease - basal ganglia change resulting in choreo-athetosis and progressive dementia in childhood and youth. Azure lunulae and Keyser fleishner rings.

Question 50

what is the lentiform nucleus?

Accepted Answer

putamen and globus pallidus

Question 51

what does the striatum consist of?

Accepted Answer

putamen and caudate

Question 52

what is sydenhams chorea?

Accepted Answer

rare but common in rheumatic fever in young females causing abnormal behaviour and generalised chorea - also called st vitus dance.

Question 53

What is hemiballismus? what is it caused by?

Accepted Answer

unilateral rapid nonrhythmic widely flinging movement of proximal arm or leg. rarely occur bilaterally. caused by lesions of cerebrovascular origin of contralateral subthalamic nucleus --mainly diabetic hyperglycaemia is a cause

Question 54

What side of the body do unilateral basal ganglia lesions result in problems with?

Accepted Answer

contralateral side

Question 55

what structure above the amygdala undergoes degeneration in Alzheimer's ?

Accepted Answer

substantia innominata

Question 56

Describe the blood supply of the spinal cord?

Accepted Answer

3 longitudinal arteries - anterior spinal artery - comes from y shaped origin of the 2 vertebral arteries at level of medulla - travels along ventral surface in midline - most vulnerable to occlusion Paired posterior spinal arteries - origin - post inferior cerebellar arteries or vertebral arteries run on POST LAT surface. radicular arteries - come from segmental vessels including ascending cervical, intercostal and lumvar arteries - pass through intervertebral foramina - divide into ant and post and run in dorsal and ventral spine roots. 1 particularly large radicular artery the great radicular artery - arise from lateral intercostal or lumbar arteries at any level from T8-L3.

Question 57

What is the venous drainage of the spinal cord?

Accepted Answer

6 longitudinal venous channels - anterior and posterior spinal veins. anterolateral and posterolateral veins bilaterally paired. All go to anterior and posterior radicular veins - intervertebral venous plexus -communicates with external vertebral venous plexus - so also ascending lumbar, azygos and hemiazygos veins

Question 58

Describe the ventricular system of the brain?

Accepted Answer

Lateral ventricle -- intervertebral foramen (or foramen of monro) -- 3 rd ventricle - narrow slit like cavity --cerebral aqueduct - 4th ventricle -- 1 foramen of magendie (median aperture) -- communicates with cisterna magna -- Subarachnoid space. Also have 2 lateral apertures (foramen of Luschka) -- subarachnoid

Question 59

describe the flow of CSF?

Accepted Answer

produced by choroid plexus in roofs of 3rd, 4th and lateral ventricle(most produced here) -- Passes through median aperture to enter cisterns magna - locates between the medulla and cerebellum -- most flows superiorly from here and is reabsorbed by numerous arachnoid villi

Question 60

3 causes of hydrocephalus? 3 symptoms?

Accepted Answer

tumours or adhesions due to injury or meningitis. papilloedema, headaches and unsteadiness

Question 61

Whats schaeffers sign?

Accepted Answer

squeeze achilles tendon and elicits an extensor plantar reflex --UMN lesion

Question 62

what does a CN 1 lesion cause? and what are its causes?

Accepted Answer

Anosmia. Frontal lobe tumour, meningitis, trauma

Question 63

What are causes of CN2 (optic nerve damage)?

Accepted Answer

optic neuritis - eye pain, impaired colour vision, uhthoff's presentation (increased symptoms with increased body temp(exercise)) - causes - Acute demyelinating ON, SLE, Behcets disease, TB, syphilis, Lyme disease, MMR. Ischaemia, compression by a tumour Vit B12 deficiency Hereditary = Lebers optic atrophy - disease of mitochondria - desaturation of colour, blurring central vision.

Question 64

What is an area of decreased visual acuity called?

Accepted Answer

scotoma

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