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Flashcards in Central Nervous System Deck (46)
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1
Q

Functions of CNS

A
basic = sensory + motor (mediated by CNS and PNS, autonomic and somatic)
higher = > consciousness, complex and learned motor skills, memory and planning, communication/language
2
Q

Brain structure

A
cerebral hemispheres:
- grey matter
- white matter
- basal ganglia
- ventricular system
brain stem
cerebellum
3
Q

Meninges

A
membranous coverings of the CNS
protective function - important in CSF production
> dura mater
> arachnoid mater
> pia mater
4
Q

Blood vessels in CNS

A

cerebral arteries -
- if blood supply to a particular part if the brain is interrupted, the patient will develop symptoms due to the lack of function of the part of the brain supplied by the vessel
cerebral veins -
- venous blood drains eventually to the internal jugular vein

5
Q

The skull

A

cannot expand
if the volume of tissue/fluid inside the skull increases the intracranial pressure rises = herniation
herniation is where a part of the brain moves from one part of the skull to the other

6
Q

Spinal chord

A
8 cervical nerve pairs
12 thoracic nerve pairs
5 lumbar nerve pairs
5 sacral nerve pairs
1 coccygeal nerve pair
7
Q

Peripheral NS

A

spinal and cranial nerves
branches off linking CNS to peripheral sensory receptors and effector organs (muscles and glands)
autonomic and somatic

8
Q

Name the cells in PNS and CNS

A
  1. neurones - the processors
  2. glial cells - supporting functions
    > Schwann cells
    > astrocytes
    > oligodendrocytes
9
Q

What area of the brain is the motor cortex?

A

pre-central gyrus

10
Q

What area of the brain is the sensory cortex?

A

post-central gyrus

11
Q

What and where is Broca’s area in the brain?

A

frontal lobe, anterior to the pre-motor cortex

predominantly responsible for speech production

12
Q

What and where is Wernicke’s area in the brain?

A

temporal lobe, posterior to auditory cortex

responsible for processing speech and comprehension of written and spoken language

13
Q

Frontal lobe

A

decision making, emotional reactions, formation of some types of memory, motor cortex, olfactory function, fluent speech

14
Q

Parietal lobe

A

sensory cortex, processing of sensory info

15
Q

Temporal lobe

A

language functions and auditory cortex, comprehension of written and spoken words, memory

16
Q

Occipital lobe

A

visual cortex

17
Q

Brain stem

A

conduction of major motor and sensory pathways, cardio-respiratory functions and consciousness, cranial nerve roots

18
Q

Cerebellum

A

precise motor control, language attention ??

19
Q

Spinal chord nerve roots

A

specific spinal nerves innervate defined motor functions and sensory territories
damage to spinal chord at specific level = loss of function of spinal nerves below that level

20
Q

What are focal neurological signs?

A

a set of symptoms or signs in which causation can be localized to an anatomic site in the central nervous system

21
Q

What is generalised neurological abnormality?

A

Essentially an alteration in level of consciousness

22
Q

Frontal lobe focal neurological signs
Parietal lobe focal neurological signs
Temporal lobe focal neurological signs

A

anosmia (loss of smell), inappropriate emotions, expressive dysphasia, motor impairment

receptive dysphagia, sensory impairment

cortical deafness, receptive dysphagia

23
Q

Spinal chord lesions

A

Physical examination helps to identify the level of injury in spinal cord lesions
Signs limited to a single dermatome or nerve root suggest either a focal nerve root injury or injury to a peripheral nerve
Signs affecting several nerve roots below a certain level eg. Complete paralysis of body and legs with maintained head and neck movement is caused by injuries to the cervical spine (usually traumatic)

24
Q

Diffuse neurological injury

A

Usually manifest as impairment of consciousness
Most often due to increased intracranial pressure
May occur as a primary process or as a secondary to response to a focal injury

25
Q

How do we assess consciousness?

A

A: alert
V: voice
P: pain
U: unresponsive

26
Q

Cerebrovascular diseases

A

strokes, TIA, intracerebral haemorrhages
2 main pathological processes:
> hypoxia, ischaemia, infarction due to impaired o2/blood supply
> haemorrhage from CNS vessels
if blood flow is decreased to a portion of the brain, survival of tissue depends on:
- collateral circulation
- duration of ischaemia
- magnitude and rapidity of decrease blood flow
reduced blood flow to the whole brain = global hypofusion = generalised neuronal dysfunction

27
Q

Stroke

A
Face (drooping)
Arms (may not be able to raise them)
Speech (slurred)
Time
loss of function lasting greater than 24 hours
2 types;
- ischaemic
- haemorrhagic
risk factors: hypertension, DM, heart disease, hyperlipidaemia
28
Q

Causes of a stroke

A

hypoxia of the brain due to blockage of blood vessels by an atheroma or embolus
bleed into the brain caused by hypertension or aneurysm
Left MCA territory infarct -
- damage to speech area in L hemisphere = loss of speech (aphasia)
- damage to L visual pathway = loss of vision to R (hemianopia)
- damage to left motor cortex and internal capsule = weakness of R face, arm and leg

29
Q

Management of strokes

A
thrombolysis
Aspirin, Clopidogrel
physiotherapy
occupational therapy
SALT
30
Q

Transient ischaemic attack (TIA)

A

temporary loss of function that resolves itself within 24 hours
“mini strokes”
symptoms similar to stroke but rapid recovery
treatment = anti-platelet therapy eg. Aspirin, Clopidogrel, control BP, lower cholesterol

31
Q

Causes of haemorrhagic events

A

hypertension, aneurysm, neoplasia, trauma, drug abuse, iatrogenic

32
Q

Intracerebral haemorrhage

A

“haemorrhagic stroke”
headache, with rapid or gradual decrease in consciousness, localises depending on site of bleed
usually arterial
few survive

33
Q

Subarachnoid haemorrhage

A

spontaneous, usually catastrophic
‘thunderous’ headache
meningitis like signs
requires neurosurgical input

34
Q

Subdural haemorrhage

A

fluctuant conscious levels
often on anti-coagulants
blood between dura and arachnoid
often minor trauma in the elderly

35
Q

Extradural haemorrhage

A

post head injury, slowly falling consciousness levels
often with fractured temporal or parietal lobe
typically middle meningeal artery

36
Q

Dementia

A

65+ increased risk
memory loss, decreased speed of thought, language, understanding and judgement affected, have difficulty controlling emotions
70% is Alzheimer’s, 15% is vascular dementia (recurrent small strokes), 15 % dementia with Lewy Bodies
assessment:
- TSH (ensure thyroid function is normal)
- CT scan
- vitamin B12, thiamine = alcoholism

37
Q

Alzheimer’s disease

A

due to loss of neurones and synapses, and accumulation of AB amyloid
leads to defects of visual-spatial skill, memory loss, decreased cognition and lack of awareness
treatment = multi-disciplinary approach, cholinesterase inhibitors eg Rivastigmine

38
Q

Epilepsy

A

a recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain
manifest as seizures which can take many forms:
- focal twitching, trance-like, convulsions
usually no identifiable cause
management =
- lifestyle changes eg. driving
- drug compliance (can have side effects = teterogenic0
eg. Sodium Valproate, Carbamazepine, Phenytoin, Lamotrigine

39
Q

Meningitis

A

diffuse infection
Bacterial: Neisseria meningitidis, Pneumococcus, Meningococcus
Viral
Fungal
presentation: EARLY - headache, cold hands and feet, pyrexial, LATE - neck stiffness, photophobia, non-blanching rash, seizures

40
Q

Brain abscess

A

focal infection
leads to focal brain damage
presents with headache, temp seizures
can spread via blood eg. embolus from bacterial endocarditis, IV drug user at risk
can spread directly eg. from an inner ear infection

41
Q

Parkinson’s disease

A

movement disorder
sporadic, familial
can be drug induced
clinically: rigidity, bradykinesia (slowness of movement), resting tremor, postural instability
treatment = MDT approach, L-dopa eg. Madopar, anticholinergic drugs eg Orphenadrine, SURGERY

42
Q

Tumours

A

benign lesions can cause problems depending on location/mass effects
can effects skull/meninges/brain itself
presentations: headaches, seizures, cognitive/behavioural change, vomiting, altered consciousness

43
Q

Tumour metastasis

A

cancer elsewhere in the body can metastasize the brain eg. breast and small cell lung cancer
eg. meningioma’s, astrocytoma’s, pituitary tumours, glioblastoma

44
Q

Meningioma’s

A

benign tumour
slow growing
derived from meningothelial cells

45
Q

Astrocytoma’s

A

range from grade 1-4, grade 4 being fatal

46
Q

Pituitary tumours

A
cause compression symptoms eg. optic nerve 
can be hormonally active 
> classified based on hormone production
eg. Prolactinoma
surgically removed transphenoidally