Neurophysiology

Question 1

What is pain?

Answer 1

Pain is an unpleasant physical or emotional sensation in response to actual or potential tissue damage and describe in terms of such damage.

Question 2

What is sleep?

Answer 2

It is a state associated with loss of consciousness from which you can be aroused by sensory stiumulation.

Question 3

How many types of sleep are there?

Answer 3

2. slow wave sleep and rapid eye movement sleep.

Question 4

Can you describe the stages of sleep?

Answer 4

There are 4 stages of slow wave sleep:
1. alpha waves interspersed with lower frequency 4-6 Hz
2.
3.
4, large amplitude, rhythmic, slow delta waves become

Question 5

What physiological changes occur during sleep?

Answer 5

CVS:
Slow wave: decrease BP, decreased CO, decreased HR + SVR
REM: increased HR, increased BP

Resp:
NREM: decreased RR + regular RR
reduced upper airway muscle tone - decrease MV + increase in airway resistance.
decreased hypoxic drive + CO2 response. - mild hypercarbia + hypoxaemia
REM: irregular breathing.
loss of skeletal muscle tone - paradoxical breathing + upper airway obstructin.

muscle tone: reduced muscle tone.

CNS: Cerebral O2 consumption reduced in NREM. increases in REM
increased CBF in REM
increased parasympathetic tone with decreased SNS activity

Endocrine:
melatonin produced
increased growth hormone. 
decreased cortisol - trough early hours of morning and inccreases during second half of sleep - peaks just after waking. 
fall in insulin + glucose levels. 
decreased metabolic rate

Temp:
thermoregulation maintained but core temp decreases by 0.5degrees C
shivering threshold decreased.