RF Flashcards
What is reticular formation
collection of cells in brain, medulla and pones
What are the functions of RF
motor, autonomic, CVS, resp control, sleep control, motivation and reword
where does RF project and what is formed by that projection
cortex and thalamus; ascending reticular activating system
what are the inputs of ascending reticular activation system
pain, smell, auditory, visual, somatosensory, visceral
what are the Outputs of ascending reticular activation system
cortex, thalamus, motor system, autonomic system
what are the neurotransmitters of reticular formation
depressing: noradrenalin and serotonin; ALSO acetylcholine and dopamine
what is the location of micturition centre
posterior reticular formation
what is the location of the Onuf’s centre
spinal cord activated by fibres form L centre
What is the role of Ach in RF
inhibition of inhibitory neurons that act on the thalamus i.e. reducing silencing of thalamus
What is the patter of Ach stimulation in RF
sleep=> Ach neurons silent; awake/paradoxical sleep=> Ach active => thalamus active
what is the feedback mechanism from the cortex to thalamus and RF
modulation of information in the thalamus; direct connection to ARAS i.e. to stop one falling asleep when inappropriate
what is the full name and function of EEG
Electroencephalography, measurement of electrical activity of the brain
What is desynchronised EEG and when is it expected
high amount of electrical activity with low amplitude => waves cancelling each other out to lose amplitude; seen in awake state and paradoxical sleep
What is synchronised EEG and when is it expected
large amplitude waves in bursts
what are the different waves seen on EEG and what are their characteristics
alpha=>8-13 Hz (occipital=> awake and eyes shut); Beta => >14HZ (parietal and frontal, awake eyes open); Theta 4-7 HZ (parietal and temporal, children/emotional adults); Delta => <3 Hz (cortical, deep sleep/serious brain conditions)
Why do we need sleep?
CNS reset, memory, homeostasis, energy conservation??
How is sleep cycle controlled
RF, hypothalamus
What are characteristics of non-REM sleep
non REM => no dreams, decreased cerebral blood flow, reduced O2, BMR reduced (I.e. breathing, BP temperature) with inactive serotonin, noradrenalin and Ach; hormone release; slow wave sleep
What are characteristics of REM sleep
active brain and inactive body => awake like wave pattern with low amplitude and high frequency; skeletal muscle paralysis (not diaphragm) dreaming, increased BMR, irregular heart rate, Ach fibres activated
how is cortex activated when one wakes up
inhibition from hypothalamus on ARAS stopped => noradrenergic firing => thalamus mediated cortex stimulation
Define insomnia
Inability to sleep => stress or depression
Define Paraosmia
Abnormal things happening during sleep…talking, walking
Define hypersomia
excessive Daytime sleepiness
Name 3 characteristics of narcolepsy why does it occur
falling sleep without warning, cataplexy, hallucinations Caused by Orexin protein in hypothalamus
name some initial stages of changing in conciseness levels
change in behaviour, mood, unsteadiness, difficulty speaking,
What are the categories of Glasgow coma score
eye opening (4), verbal responses (5), motor responses (6)
what is the scoring of Glasgow score
Max 15, mild 13, moderate 9, severe <8
what are coming causes of disturbances of consciousness
metabolic (hypoglycaemia uraemia, hypoxia), trauma (brainstem, bruising), space occupying lesion
Define Coma
State of impaired consciousness in which the patient is not roused by external stimuli.
What are characteristics of locked in syndrome
patient conscious (normal RF) but damage to pones (corticospinal/bulbar tracts) leads to full paralysis, eye movement often preserved
define delirium
clinical syndrome that involves abnormalities of thought, perception and levels of awareness. It is typically of acute onset and intermittent.
What are common causes of delirium
acute (UTI, phenomena, meningitis); benzodiazopim, morphine, post-op, alcohol, CO poisoning, hypoglycaemia electrolyte disturbances, brain trauma/haemorrhage, brain cancer, B12 deficiency, thiolate deficiency,
Define decorticate response
isolation of cortex from the brain due to severe injury => thalamus and cortex connection destroyed
what are the characteristics of decorticate response
extended LL and flexed UL (brainstem reticular inhibition intact) patient unconscious BUT responsive to pain
define decerebrate response
lower brain/brainstem damage no inhibition from RF on descending motor tracts
what are the characteristics of decerebrate response
increased muscle tone, extension of UL and LL, extension to pain stimulus
What are the important parts of limbic system
hippocampus, olfactory bulb, fornix, anterior thalamic nuclei, septum pallidum, cingulate gyrus
What are the functions of limbic system
emotions, behaviour, motivation, long-term memory, olfaction
