2.5 Sleep and Conscioussness

Question 1

is nrem or rem the majority of sleep

Answer 1

nrem

Question 2

nrem characteristics 3

Answer 2

movement and sensation limited

parasympathetic activity

energy consumption and body temp low

Question 3

rem characteristics 4

Answer 3

muscle paralsysis

sympathetic activity

oxygen consumption increases

resp and heart rate irregular

Question 4

sub stages of nrem

Answer 4

stage 1-4

Question 5

stage 1 nrem 2 characteristics 2 types of waves

Answer 5

jerks
hallucination
alpha and theta waves

Question 6

stage 2 nrem one wave two features

Answer 6

theta waves
sleep spindles
k complexes

Question 7

stage 3 wave and 2 characteristics

Answer 7

reduced eye and body movement
theta and delta waves

Question 8

stage 4 one characteristic one wave

Answer 8

deep sleep
sleep talking delta waves

Question 9

what are sleep spindles

Answer 9

bursts of rapid rhythmic brain activity potentially to inhibit cognitive processes and maintain a tranquil sleep state

Question 10

k complexes

Answer 10

sharp hugh amplitude negative wave followed by positive wave

involved in memory

Question 11

wavelengths most active to sleepy

Answer 11

g -> b -> a -> theta -> delta

Question 12

what is the reticular formation

Answer 12

contains the aras - ascedning reticular activating system

Question 13

what is the role of the aras system

Answer 13

has nuclei which increase firing of wake promoting areas around the brain

Question 14

key structures involved in sleep 4

Answer 14

reticular formation - contains aras
lateral hypothalamus - contains VLPO
anterior hypothalamus
suprachiasmatic nucleus

Question 15

what is important for sleep in the anterior hypothalamus

Answer 15

it contains the ventrolateral preoptic area VLPO

Question 16

function of the lateral hypothalamus in sleep

Answer 16

releases orexin whcih activates aras promoting wakefullness

Question 17

function of vlpo

Answer 17

contains neurons whcih releasing gaba whcih acts on the ARAS to prevent them firing and promote sleep

Question 18

what is process c in sleep

Answer 18

process c is the circadian rhythms they are modulated by zeitgebers (external) and the suprachaismatic nucleus

Question 19

what is the role of the suprachiasmatic nucleus

Answer 19

contains specialised light sensitive ganglion cell in retina which become activated in presence of sunlight

releases orexin

Question 20

role of orexin

Answer 20

maintains wakefullness

Question 21

what is process s 2

Answer 21

homeostatic sleep drive. Involves the VLPO which fire faster to inhibit the ARAS

Question 22

brain death def

Answer 22

irreversible cesation of brain fucntion including brainstem reflexes

Question 23

minimally conscious state

Answer 23

aletered state of consciousness w minimal but detectable awareness and response

Question 24

vegetative state

Answer 24

pt completely unaware of self/environment but sleeps, hypothalamus and brain stem work

Question 25

coma

Answer 25

alive but does not respond to anything

Question 26

locked in syndrome

Answer 26

state of alert wakefulness w paralysis

Question 27

akinetic mutism

Answer 27

marked reduction in drive w complete loss of action/spontaeneity, speech, anormal

Question 28

key requirements to maintinaing consciouscness

Answer 28

oxygen glucose neural activity and connectivity

Question 29

key brain regions involved in arousal and awareness 3

Answer 29

reticular formation thalamus cortex

Question 30

different main causes for loss of consciouscness 4

Answer 30

neurally mediated cardiovascular derived neuro psychogenic

Question 31

syncope

Answer 31

sudden brief transeint loss of consciouscness with postrual failure to due cerebral hypoperfusion

Question 32

key causes of syncope 7 2 subgroups neurally mediated and cardiac

Answer 32

Neurally mediated: vasovagal orthostatic hypotension iatrogenic hypovalemia primary/secondary autonomic failure Cardiac: rhythm/conduction issures mechanical obstructuion/failure

Question 33

why does vasovagal syncope occur

Answer 33

due to autonomic dysfunction whereby stimulus triggers initial exagerated symapthetic tone and then increased parasympathetic tone resulting in stimuli

Question 34

why does orthostatic hypotension occur

Answer 34

stand, blood volume pools due to gravity, bp drop results, inadequate baroreceptor reflex

Question 35

reflex pathway whcih maintains normal perfusion

Answer 35

stand bp drops baroreceptors detect relayed to medulla decrease parasympathetic tone, increase sympathetic tone vasoconstriction increased heart rate raise bp

Question 36

investigations in loss of consciousness 8

Answer 36

Primary survey GCS pupil reflex check bloods cxr eeg lumbar puncture toxicology