Sleep and hypnotics first half 1.0 Flashcards
What is sleep?
A readily reversible state of reduced responsiveness to, and interaction with, the environment
What is obtundation?
a state of consciousness from which only painful stimuli will return the patient to full consciousness
Functions of sleep?
Restorative, protective adaptation, metabolism/weight homeostasis, memory consolidation and integration
What is restored during sleep?
cortical recovery and tissue repair
Why is sleep a protective adaptaiton?
protection from nocturnal predators
What does an electroencephalogram (EEG) record?
The activity of populations of neurons in the brain
What does the frequency of an EEG show?
How fast the neurons are firing
What does the amplitude of an EEG show?
The amount of neurons firing in synchrony
What does an EEG sum show?
The summed activity from multiple electrodes
What does it mean for nerve cells to be synchronised?
They are all firing together
What are the amplitude and frequency characteristics of desynchronised neurons?
Fast wavelength, low amplitude
What are the amplitude and frequency characteristics of synchronised neurons?
Slow wavelength, large amplitude
Delta rhythms?
Slow (4Hz) and large amplitude, deep sleep
Theta rhythms?
SLow (4-7Hz), light sleep
Alpha rhythms?
Fast ish (8-13Hz), conscious relaxation
Beta rhythms?
fastest (>14Hz), awake and alert
Gamma oscillations?
Memory encoding, recall and attention
Two categories of sleep?
Rapid eye movement (REM) and non-rapid eye movement (NREM)
REM duration and activity?
~20 mins, dreaming
NREM length
60-90 mins
What happens to the length of NREM stages as you progress through the night
gets shorter
What happens to the length of REM stages as you progress through the night
gets longer
Awake rhythms?
alpha and beta
How long does stage one NREM sleep last?
5 min
Type of rhythms in REM sleep?
beta
Stage 1 NREM characteristics?
5 mins, theta rhythms, starting to fall asleep, nerves begin to become synchronized
Stage 2 NREM characteristics?
1-15 mins, spindle and k complex rhythms
Stage 3 NREM characteristics?
5-25 mins, no eye/body movements, delta rhythms, restorative sleep
Stage 4 NREM characteristics?
Deep sleep, 20-40 mins, delta rhythms
What is the EEG of REM sleep similar to?
an active, waking brain
When does dreaming occur?
REM sleep
What is REM sleep referred to as?
An active, hallucinating brain in a paralysed body
What kind of nerve activity predominates in REM sleep?
sympathetic
What is increased in REM sleep as a result of sympathetic activity?
Heart rate, respiration rate and blood flow to the penis
Changes in NREM sleep?
muscle tension reduced, temp lowered, energy consumption lowered, more parasympathetic activity
