7. Nervous system Flashcards
Role of nervous system?
= processing information, conducting messages, controlling the movement of muscles and storing our memories
Define pain?
= an unpleasant feeling that is conveyed to the brain by sensory neurons
- involves integration of stimulation of nociceptors, bare sensory nerve endings and input from higher brain centres, emotions and activities do modify the pain experience
Compare Acute and chronic pain
acute = Rapid onset, well localised, responds to analgesics
Chronic
- slowly developing continuous or recurring pain
- difficult to treat as is learned response
What are the different types of pain (5)?
Somatogenic = due to recognisable physical cause
psychogenic = no obvious physical cause e.g. IBS
visceral = poorly localised pain from organs in thoracic and abdominal cavity
somatic = well localised pain from skin, muscles or joints and responds to analgesics
referred = visceral pain which is perceived as somatic pain in an area with the same innervation
why might neuropathic pain develop in an amputee in the affected limb?
- Pain is attributed to nerve remodelling where the sodium channels are more easily activated or are leaky
- The thalamus and cortical structures are also likely to be involved and the perception of pain is the affected limb may be related to changes in brain and not the periphery
- Changes in the spinal cord are also implicated were changes in the responsiveness of NMDA glutamate channels occur
Pathophysiology of
Motor neurone disease
- Is associated with the degeneration of upper and lower motor neurons ‘
- Axons of the affected nerve degenerate leading to muscle wasting which begins as weakness and progresses to fatal paralysis
Pathophysiology of:
parkinson’s disease
- Degeneration of dopamine neurons
- This leads to observable changes in the structure and function of the brain and spinal cord
Pathophysiology of:
Huntington’s disease
- Is an autosomal dominant genetic disorder that results in loss of neurons in the basal nuclei causing a decrease in activity of the inhibitory neurotransmitter GABA
Pathophysiology of:
Multiple sclerosis
- Is an autoimmune disorder whereby immune cells destroy CNS myelin leading to plaque formation and causing impairments in motor, sensory and neurological function.
Pathophysiology of:
Spinal cord injury
Consists of primary and secondary phase of injury
- Primary phase the injury to the spine directly exerts force to the spinal cord disrupting axons, blood vessels and cell membranes
- Neurological deficits are present immediately - Secondary phase leads to tissue destruction and involves inflammation, oedema, vascular dysfunction ischaemia, excitotoxicity and delayed apoptotic cell death
Pathophysiology of:
Traumatic brain injury
- Primary head injury results immediately from the trauma e.g. contusion
- Secondary head injury occurs from processes initiated by the trauma
o Occurs days to weeks after the injury and plays a major role in the brain injury and death of a patient following a TBI
o May bee from ischemia, increased ICP, cerebral oedema
Pathophysiology of Ischemic stroke
- Blood vessel becomes narrowed and a blood clot forms causing a blockage
- The blockage starves the brain of oxygen
- Can be thrombotic or embolic
- Thrombotic – results when thrombus blocks the blood vessel and deprives the brain tissue of oxygen and nutrient rich blood
- Embolic stroke occurs when fragments from a thrombus that has formed in the blood vessels everywhere in the body, travels to the blood vessels in the brain and causes a blockage
Pathophysiology of haemorrhagic stroke
- Blood vessels ruptures in the brain causing permeant damage (may be due to an aneurysm or hypertension)
- Results from bleeding in the brain
