Biospcyhology - Circadian, Infradian And Ultradian Rhythums Flashcards
What is an endogenous pacemaker?
Internal body clocks that keep biological processes to time.
What is an exogenous zeitgebers?
External cues that train internal body clocks meaning altering body clocks to match the environment.
What is a circadian rhythm?
A biological rhythm that lasts about 24 hours.
What types of things do we have circadian rhythms for?
Regulating sleep and wake, the release of hormones, varying our body temperature and blood pressure.
What is the suprachiasmatic nucleus?
The endogenous pacemaker for the sleep wake cycle. The SCN is part of the hyper Aalam within the limbic system. It’s located at the opticchiasm, the point on the optic nerves where they cross. When light is detected from the SEN, it sounds light to the pineal gland stopping the production of melatonin a hormone that results in a sleep response.
What is lights role in the sleep wake cycle?
Light is thought to be the primary exogenous zeitgeber in the sleep cycle. Social cues like when we time our meals or exercise when others go to bed or environmental cues like clocks are also thought to act as EZ.
What was Siffre study?
Tested the free running predictable sleep weight cycle by spending 179 days in a cave with no natural light or other potential EZ’s such as clocks or social cues. Siffre’s body clock maintained a regular cycle of around 25 hours without EZ’s longer than the expected 24 hour cycle. Suggesting the EP for the sleep cycle is free running but needs entertainment to keep the 24 hour day night cycle.
What is a criticism of Siffre study?
Psychologists have criticised the use of artificial lights in isolation experiments on the sleep cycle suggesting the artificial lights disrupted measurements of the free running circadian rhythm by acting as an EZ.
What is an infradian rhythm?
A biological process that repeats less frequently than once every 24 hours so it occurs weeks or months.
What is the menstrual cycle?
An infradian rhythm that lasts 28 days with a six day period of fertility however cycles can be shorter or longer ranging between 24 and 35 days.
What are the biological aspects of the menstrual cycle?
Releasing the egg the thickening of the womb lining and losing the womb lining during menstruation. These biological changes are regulated by the hormones, oestrogen pre-ovulation and progesterone post ovulation. The levels of these hormones act as endogenous pacemakers keeping the biological processes to time acting as an internal body clock for the menstrual cycle.
What is an ultradian rythums?
A biological process that repeats more frequently than once every 24 hours minutes/Hours.
What are the four stages of sleep?
Stage is 1-3 are REM sleep or NREM. Stage four is rapid eye movement sleep most dreams occur in this one cycle takes around 90 minutes and repeats 4 to 5 times over the course of a night sleep.
What is N1/light sleep?
The falling asleep sensation it is easy for the body to wake or suddenly move, e.g. hypnic jerks. There may be a sensation of falling mild auditory or visual hallucinations.
What is N2 sleep?
Deep asleep: harder to wake the body is relaxed heart rate and body temperature are lowered and the eyes are still.
What is N3/deepest sleep?
Very difficult to wake body at its most relaxed with heart rate at its lowest.
What happens in REM sleep?
Brain returns to active state passing back through N2 and N1. REM is similar to Wakefield as seen on EEG however the body is paralysed. Characterised by rapid movement and is associated with dreaming as when woken people will report vivid dreams in this stage.
