Oxygenation pt 2 and Sleep Flashcards
The rate that haemoglobin binds and releases oxygen is regulated by:
- temperature - blood pH - PCO2 - PO2 - BPG
What is the Bohr effect?
A shift to the right on the O2 saturation scale. A weakening of the haemoglobin-oxygen bond Happens when temperature increases or blood pH decreases
How is CO2 transported in the blood?
- 5% dissolved in plasma - 20% bound to haemoglobin a carbaminohaemoglobin when O2 leaves the blood - 75% as bicarbonate ions (HCO3) - alkaline
What are the influences of CO2 on blood pH?
- the carbonic acid-bicarbonate buffer system resists blood pH changes - if H+ concentration in the blood rises, excess H+ is removed by combining with HCO3- to make carbonic acid - if H+ concentrations drop, carbonic acid dissociates, releasing H+
What is the Haldane effect?
Oxygenation of blood in the lungs displaces carbon dioxide from hemoglobin which increases the removal of carbon dioxide. Conversely, oxygenated blood has a reduced affinity for carbon dioxide
What is an EEG?
- an electroencephalogram - records electrical activity of the brain - used to diagnose epilepsy, sleep disorders and brain death
What are the four types of recorded brain waves?
Alpha. When awake but relaxed. 8 - 13Hz Beta. Awake and alert/concentrating. 14 - 30Hz Theta. Usually appear in children. 4 - 7Hz Delta. When in deep sleep or under anaesthesia. <4Hz
What are the stages of sleep?
Non Rapid Eye Movement (NREM) - stages 1 - 4 Rapid Eye Movement (REM)
What causes homeostatic imbalances in sleep?
- Alcohol - Drugs can both impair sleep and cause sleep - Narcolepsy is a disorder where suffers go from waking to deep sleep without warning. - Cataplexy is a condition where skeletal muscles go lax while awake - Insomnia is the inability to sleep - Sleep apnoea is the blocking of the airways while sleeping.
What is NREM sleep?
- goes from easy arousal (stage 1) to deep sleep (stage 4) - blood pressure and heart rate drop - at stage 4, arousal is difficult. - bedwetting, night terrors and sleepwalking all occur during stage
Why is NREM important?
- winds the body/mind down - is restorative
What is REM sleep?
- dreaming sleep - EEG is irregular - heart rate, resp rate, BP and oxygen use all increase - decreased GI motility - limp skeletal muscles
Why is REM important?
- analysis of the day’s events - problem-solving - organising - mood stabilising
What is the Reticular Activating System?
- RAS - an area in the brain stem - sends stimuli to the cerebral cortex to keep you alert - has a role in the sleep stages
How does the hypothalamus relate to sleep?
- Inhibits RAS - Induces and regulates sleep - releases acetylcholine, a ‘wake up’ chemical
