central nervous system Flashcards
functions of the nervous system?
sensory and motor functions; mediated by the PNS and CNS, consciousness, motor skills, memory and planning, communication/language
parts of the central nervous system?
brain and spinal cord
components of the peripheral nervous system?
autonomic e.g. breathing, somatic e.g. movement
parts of the brain?
cerebral hemispheres, brain stem, cerebellum, frontal lobe, parietal lobe, occipital lobe, temporal lobe
describe meninges and their function
membranous coverings of the CNS, with a protective function and production of cerebrospinal fluid. they have dura mater, arachnoid mater, pia mater
function of cerebral arteries?
to supply a defined territory within the cerebral cortex
what happens if blood supply to a particular part of the brain is interrupted?
the patient will develop symptoms due to lack of function of the part of the brain supplied by that vessel.
describe the skull:
a bony box which cannot expand; if the volume of tissue or fluid inside the skull increases, the intracranial pressure rises.
what is herniation?
where one part of the brain moves from one compartment of the skull to another.
explain spinal cord nerves
8 cervical pairs, 12 thoracic pairs, 5 lumbar pairs, 5 sacral pairs, 1 coccygeal pair
what protects the spinal cord?
the vertebral column
two types of cell in the nervous system?
neurons - processors that carry electrical impulses between the CNS and PNS. glial cells - supportive functions
examples of glial cells?
schwann cells, astrocytes, oligodendrocytes
describe the function of the frontal lobe?
executive functions involved in decision making, emotional reactions, memory, motor cortex, olfactory function, generation of fluent speech
function of parietal lobe?
cell movement and sensory cortex; processing sensory information
function of occipital lobe?
visual cortex; responsible for vision.
function of temporal lobe?
language functions including auditory cortex and comprehension of written/ spoken words
function of cerebellum?
precise motor control - coordination, balance and movement
function of brain stem?
cardiovascular and respiratory functions; conduction of major motor and sensory pathways
function of limbic system?
memory and basic emotion
location of sensory and motor territories?
post central gyrus = sensory cortex. pre-central gyrus = motor cortex
areas of the brain responsible for speech and language;
brocha’s area - in the frontal lobe, responsible for speech production. Wernicke’s area - temporal lobe, speech processing and comprehension of language
what happens if the spinal cord is damaged?
loss of function of spinal nerves below that level.
describe focal neurological signs??
symptoms where causation can be localized to an anatomic site in the CNS.
what is meant by ‘generalised neurological abnormality’ ?
an alteration in levels of consciousness
causes of reduced consciousness?
trauma, hypoxia, hypothermia, hypoglycaemia, post-ictal state in epileptic patient.
what is cerebrovascular disease?
strokes, TIA’s, intracerebral haemorrhages. it is the leading cause of mortality and morbidity.
pathological processes of cerebrovascular disease?
1) hypoxia, ischaemia and infarction due to impaired blood supply and oxygenation. 2) haemorrhage from CNS vessels.
when blood flow is reduced to a portion of the brain, what does tissue survival depend on?
collateral circulation, duration of ischaemia, magnitude and rapidity of flow reduction.
causes of stroke?
1) hypoxia to the brain due to blockage of blood vessel by atheroma or embolus. 2) bleed to the brain
what would damage to left MCA territory do?
it would damage the speech area in left hemisphere leading to loss of speech, visual pathway and vision to the right side. damage to left motor cortex would lead to weakness of right face, arm and leg.
causes of haemorrhagic events?
hypertension, vascular malformation, neoplasia, trauma, drug abuse, latrogenic
describe an intracerebral haemorrhage and what patients will present with;
stroke - bleeding within the brain tissue. patients present with headache, and a decrease in consciousness level. usually in arterial origin.
describe a subarachnoid haemorrhage?
bleeding on the surface of the brain, spontaneous and catastrophic. signs are; headache, meningitis like signs.
describe a subdural haemorrhage?
blood collects between skull and surface of the brain. patients present with fluctuating conscious level and are often on anticoagulants
describe a extradural haemorrhage?
blood forms between inner surface of skull and outer layer of dura. occurs post head injury with falling conscious levels and possibly a lucid period.
describe dementia?
progressive and largely irreversible clinical syndrome with widespread impairment of mental function.
what does dementia cause in patients?
memory loss, speed of thought, affects language, understanding and judgement, difficulty in controlling emotions
describe a dementia assessment?
TSH to ensure thyroid function is normal, CT scan to check for intracranial pathology, vitamin B12; for thiamine for alcoholism
what causes Alzheimer’s disease?
an accumulation of AB amyloid, tau-neurofibrillary tangles and plaques, loss of neurones and synapses.
patient presentations with Alzheimer’s disease?
defects in visual-spatial skills, memory loss, decreasing cognition and ansognosia (lack of awareness)
describe epilepsy?
a recurrent tendency to spontaneous, intermittent abnormal electrical activity in part of the brain, manifesting in seizures
drugs used to treat epilepsy?
sodium valproate, carbamazepine, phenytoin, lamotrigine
types of meningitis?
bacterial (Neisseria meningitides, pneumococcus, meningococcus), viral and fungal
what is a brain abscess?
focal infection that can lead to focal brain damage. patients present with headaches, seizures, and a temperature.
signs and symptoms of meningitis?
headache, cold hands and feet, pyrexia, neck stiffness, photophobia, kerning’s sign, non-blanching rash, seizures
describe Parkinson’s disease?
a movement disorder, can be sporadic or familial. causes postural instability due to the progressive degeneration of the dopaminergic nigrostriatal system.
signs and symptoms of Parkinson’s disease?
rigidity, bradykinesia, resting tremor, postural instability.
signs of brain tumours?
headaches, seizures, cognitive or behavioural change, vomiting, altered consciousness.
what is a meningioma?
a benign tumour that arises from the arachnoid cells. derived from meningothelial cells.
examples of brain tumours?
meningioma, astrocytoma’s, pituitary tumours
