Consciousness + sleep

Question 1

What is consciousness?

Answer 1

The awareness of objects + events in the external world + sensation, mental experiences + existence at any given moment

Question 2

2 distinct types of consciousness

Answer 2

• Normal Waking Consciousness
  awareness of internal states + external surroundings when awake + unaffected by sleep, drugs etc
  -Alter State of Consciousness
  anything that is not NWC

Question 3

What is Sleep

Answer 3

Reversible behavioural state of perceptual disengagement from & unresponsiveness to the environment

Question 4

What is the Suprachiasmatic Nucleus?

Answer 4

A tiny region in the hypothalamus

• controls circadian rhythms (sleep/wake cycles that occur approx every 24hrs)
• detects amount of light being sent to brain & uses info to hypothalamus to influence amount of melatonin being released into bloodstream

Question 5

What is melatonin?

Answer 5

• hormone produced + secreted by the pineal gland
• associated with sleep/wake cycle
• builds up during day
• once melatonin reaches critical level -> fall asleep
• ^ light = v melatonin

Question 6

What is pineal gland?

Answer 6

Keeps track of body’s natural cycles + registers external factors

• light info from SCN sent here

Question 7

What is the reticular activation system?

Answer 7

Main purpose: regulate cortical arousment ie alertness
-influences when we are asleep/awake by restricting amount of stimulation the cerebral cortex receives
Major parts: reticular formation + thalamus

Question 8

What are reticular formations

Answer 8

• runs through brain stem + up into mid brain
• critical in reducing stimuli sent to cerebral cortex

RF stimulated = alertness
RF damaged = coma

Question 9

Thalamus role in reticular activation system

Answer 9

• transfer station for information coming from senses
• transfers neural info from the RF to cerebral cortex
• filters sensory info
• transfers info from cerebral cortex to brain stem
• closes sensory pathways during sleep

Question 10

Damage to thalamus in reticular activation system

Answer 10

• loss of sense (except smell)
• -> cerebral cortex NOT receiving sensory info
• attention difficulties (what to ignore/attend to)
• lower arousal from lethargy -> coma

Question 10

Damage to thalamus in reticular activation system

Answer 10

• loss of sense (except smell)
• -> cerebral cortex NOT receiving sensory info
• attention difficulties (what to ignore/attend to)
• lower arousal from lethargy -> coma