Neurology and homeostasis

Question 1

disease and homeostasis

Answer 1

• A disease is any failure of normal physiological function and leads to negative symptoms
• While disease is often a result of infection or injury, most diseases involve disruption of normal homeostasis
• Anything that prevents positive or negative feedback from working correctly could lead to disease if the mechanisms of disruption becomes strong enough

Question 2

receptors

Answer 2

• Baroreceptors - pressure specifically in vessels arteries and veins (blood pressure) baroreceptors
• Chemoreceptors - gases/chemical substances gas change or chemical 02 and C02
• Mechanoreceptors- stretch, muscles, uterus
• Nociceptors- pain
• Photoreceptors - light
• Thermoreceptors - temperature

Question 3

Some causes of neurological deterioration

AEIOU TIPSS

Answer 3

• Alcohol
• Epilepsy
• Insulin (low blood sugar acts as a neurological dysfunction)
• Opiates
• Uremia
• Tumor
• Injury
• Psychiatric
• Stroke
• Sepsis

Question 4

priority nursing interventions

Answer 4

positioning - head of the bed at 30 degrees

• supplemental oxygen
• oral care
• maintenance of BP
• administer analgesia to reduce SNS response and pain
  
  • Administer stool softener to prevent constipation
  • Re-orientate the patient to time and place to reduce anxiety
  • Pressure injury care

Question 5

localized brain injury

Answer 5

Localized/focal

• Coup= direct impact
• Contrecoup = secondary damage away from injury site
• Common example, car accident coup hitting the head on the steering wheel, contrecoup hitting head back on the car seat

Question 6

widespread diffuse

Answer 6

• Diffuse axonal injury (brain stem, closed head injury) coma, mortality 33-50%
• Example= shaking a baby

Question 7

monro-kellie hypothesis

Answer 7

• States that the sum of volume of brain, cerebrospinal fluid (SCF) and intracerebral blood is constant
• An increase in one should cause reciprocal decrease in either one or both remaining two
• What fits in the box fits in the box (if there is an increase in anything, other others have to decrease to maintain equilibrium)

Question 8

increased intracranial pressure (ICP)

Answer 8

• Occurs when there is an imbalance inside the cranium, following brain injury or other medical conditions that cause an increase of pressure inside the skull

Question 9

pathophysiology of raised increased intracranial pressure (ICP)

Answer 9

• A rise in ICP greater then cerebral perfusion pressure (CPP), results in reduced blood flow to the brain as vessels are squashed from the pressure
• Reduced blood flow= reduced oxygen and glucose delivery which results cerebral ischemia

Question 10

Sympathetic VS parasympathetic ICP

Answer 10

• Cerebral ischemia stimulates the sympathetic nervous system to increase BP and HR to increase cerebral perfusion and thus increase oxygen and glucose delivery
• Baroreceptors detect the rise in BP by reducing the HR
• Without intervention this cycle continues. The sympathetic nervous system continues to activate an increase in BP to increase perfusion and the parasympathetic nervous system continues to activate a decrease in HR to lower the increasing BP
• Continued increase BP causes a further increase in ICP and therefore an increase in cerebral ischemia
• The increasing pressure inside the cranium leads to compression of the brainstem causing irregular breathing
• Following this death is imminent

Question 11

crushings triad

Answer 11

increased SBP (systolic BP)
decreased HR
increased or decreased RR
= death

Question 12

cushing’s reflex

Answer 12

Compromise CBF (due to raised ICP) initiates a cascade of physiological responses

• Raise in ICP greater than CPP causes cerebral ischemia
• Cerebral ischemia stimulates a sympathetic response (>BP, >HR) to provide more 02
• Raised BP stimulates baroreceptors and initiates parasympathetic response (to counteract the >BP) causing a < HR
• Ongoing >BP causes further increased ICP (and