Reticular formation and Limbic system Flashcards
What are the Reticular formation (RF) functions?
- Control of skeletal muscles
- Control of somatic/visceral sensations
- Control of ANS
- Control of endocrine functions
- Influence on circadian rhythms
- Control of levels of consciousness
where does the Reticular formation extend through?
The RF can be divided into cell columns in the brainstem, what are these?
what structures can we find in each?
brainstem
- Median: raphe nuclei
- Medial: motor coordination
- Lateral: breathing (expiration)
identify the reticular formation median, medial, and lateral cell columns within the brainstem.
what forms the Ascending Reticular Activating System (ARAS)?
What is the funcitno of the ARAS?
ACh/NE axons project from the rostral RF to intralaminar nucleus of thalamus which in turn project to the cortex
maintains consciousness.
Thalamic lesions can result in coma if what structure is affected?
intralaminar nuclei
Transection through midbrain results in disconnection of ARAS from cortex will result in what?
Transection through lower medulla/uppermost part of spinal cord will result in what?
Transection at midpontine level will result in what?
Produces coma or slow-wave sleep.
ARAS functions normally.
Constant wakefulness
wakefulness produced by midpontine transection suggests what?
that lower regions of the RF (below the transection) are involved in ‘turning off’ the ARAS periodically
so lower part controls sleep/wakefulness cycles.
serotonin depletion causes what?
Raphe afferents synapse where?
Serotonin neurons are found where?
insomnia
at various levels of the Reticular formation
Raphe nucleus
ARAS projections also inhibits what and what is its funciton?
Is sleep an active process? why?
what turns off the ARAS? how does it work?
the reticular nucleus of the thalamus, which normally functions to inhibit the relay of sensory information to cortex.
yes, because parts of the brain have to work to maintain sleep (thalamus, raphe, hypothalamus).
the reticular nucleus; During sleep, this nucleus actively inhibits sensory transmission through the thalamus allowing to you to sleep better because you’re less aware of external environment.
what is habituation?
what structure is involved in habituation?
brain ignores repetitive stimuli
reticular formation
Identify the ‘states’ of consciousness
- Confusion: Disorientation, ‘not thinking clearly’
- Somnolence: Semi-consciousness or drowsiness. Stimuli will arouse patient but only for the duration of the stimuli.
- Stupor: Patient responds in a limited way to painful, or extremely intense, stimuli.
- Coma: No response to external stimuli.
The Glasgow Coma Scale tests which 3 responses?
how many points are in each of the responses?
visual - 4
verbal - 5
motor - 6
what are the point given for the eye response in the glasgow scale?
- No eye opening.
- Eye opening to pain.
- Eye opening to verbal command.
- Eyes open spontaneously.
what are the point given for the verbal response in the glasgow scale?
- No verbal response
- Incomprehensible sounds.
- Inappropriate words.
- Confused
- Orientated
what are the point given for the motor response in the glasgow scale?
- No motor response.
- Extension to pain.
- Flexion to pain.
- Withdrawal from pain.
- Localising pain.
- Obeys Commands.