The stages of the sleep cycle

Question 1

What are stages of the sleep cycle

Answer 1

complete cycle is 90-110 mins and divided into 5 stages. Stage 1 – light sleep, muscle activity slows with occasional twitching.Stage 2 – breathing and Hr slows, slight decrease in body temperature 0 50% of sleep is stage 2.Stage 3 – deep sleep begins- brain generates slow delta waves.Stage 4 – very deep sleep rhythmic breathing with limited muscle activity.Delta waves are

produced.Stage 5 – REM – rapid eye movement – brainwaves speed up and dreaming occurs.There is an increase in HR and breathing is rapid and shallow. – 20% of sleep is rem sleep.The first cycles have relatively short periods of rem and long periods of deep sleep but later in the night – rem periods lengthen and deep sleep time decreases.

Question 2

What does ecg stand for and what is it?

Answer 2

Electroencephalography

Question 3

What are the waves,their ranges and how do they work?

Answer 3

Measurement of electrical
activity produced by the brain in the cerebral cortex. It can be recorded from
electrodes placed on the scalp.

Question 4

Physilogical function of ARTs

Answer 4

Require the whole set of redundant NTs, supressing
ARAS induces and maintains sleep

Question 5

What are the pathways that dopamine is involved in 4. Major pathways:

Answer 5

• Mesolimbic pathway – an excess of DA in this pathway has been linked to psychosis and positive symptoms of schizophrenia such as hallucinations and delusions
• Mesocortical pathway – problems with DA dunction in this pathway – resp for negative symptom and cognitive defects such as flattening emotion and reduction in attention memory.
• Nigostiatal pathway – involved in motor cell control and parkinsons.
• Tuberoinfudibular pathway – involved in hormone secretion

Question 6

What are sleep regulatory substances?

Answer 6

Neuromodulates modulate neurotransmitters. When a neuron is active, it generates ATP.ATP signalling can regulate both excitatory and inhibitory neurotransmission. ATP surges during the initial hours of sleep, displaying a significant positive correlation with the intensity of slow-wave activity in non-rapid eye movement (NREM) sleep.Intracellularly, ATP is metabolized to ADP then to AMP, then to adenosine

Question 7

How are Sleep-regulatory substances are involved in synaptic scaling?

Answer 7

Sleep- regulatory substances are involved in synaptic scaling, which increases or decreases the efficiency of synaptic efficiency. Events or skills are remembered if they are novel or emotional, mediated by the brain itself. If the brain decides the event is not important, the synapse is depressed; if the brain decides something is worth remembering, synapses stay active (potentiated) or depressed.