Consciousness and Brain Activity Flashcards
What is the medical definition of consciousness?
State of awareness and responsiveness to one’s surroundings
What is the “lowest” level of consciousness?
Brain death
Describe Locked in Syndrome
Patient has awareness, sleep-wake cycles, meaningful behaviour but is isolated due to facial / muscle paralysis
Describe a state of normal loss of consciousness
Sleeping
Describe three states of abnormal loss of consciousness
Coma
Anaesthesia
Vegetative State
What is the most common cause of serious loss of consciousness worldwide?
Cerebral malaria
Aside from Cerebral Malaria, give 4 other causes of losing consciousness
Stroke Cardiovascular Diabetes Drug-induced Epilepsy Head Injury Dementia
What is AVPU?
A way of assessing patient’s responsiveness
A: Patient is awake
V: Patient responds to voice
P: Patient responds to pain
U: Patient unresponsivess
A fully conscious patient has a GCS of..?
15 (maximum)
A person in a deep coma has a GCS of..?
3 (minimum)
What are the three variables measured for the Glasgow Coma Scale?
Best Eye Response (E)
Best Verbal Response (V)
Best Motor Response (M)
To be in a coma, patient would have a GCS of..?
8 or less
A GCS of 9 - 11 is..?
Moderately severe injury
A GCS greater than or equal to 12 is..?
Minor injury
What is the criteria for brain stem death?
Irreversible loss of capacity for consciousness, to breathe, and loss of brain-stem function
Give examples of 5 brainstem reflexes
- Pupil response
- Corneal reflex
- Vestibular-ocular reflex (VOR)
- Cough / gag reflex
- Respiratory effort
What is the main system in the brain which regulates consciousness?
Reticular Activating System
What is the Reticular Formation?
A collection of nuclei belonging to the Reticular Activating System, found in the mid-brain. Diffuse, no clear boundaries
What are the four principle sets of nuclei in the Reticular Activating System?
Locus Coeruleus
Raphe Nuclei
Ventral Tegmental Area
Cholinergic Nuclei
What are the Neurotransmitters used in each of the Nuclei of the RAS?
Locus Coeruleus: NA
Raphe Nuclei: 5-HT
Ventral Tegmental Area: DA
Cholinergic Nuclei: ACh
What are the two main types of sleep?
Synchronised / NREM / Non-REM
Desynchronised / REM
The sleep-wake cycle is controlled by what fibres in the RAS?
Cholinergic Nuclei
Oscillations in the EEG are generated by interactions between which 3 neurones?
- Thalamocortical
- Reticular
- Corticothalamic
During wakefulness, what sort of oscillatory waves are there?
Alpha and beta waves
How long is the body clock’s day?
24.5 - 25.5 hrs
