Biological Rhythm Flashcards
What are biological rhythms
Repeated patterns of changes in the body that are regulated by an internal clock
Define circadian rhythms and give an example
Circadian Rhythms last for 24 hours
Example: Sleep/Wake Cycle - rhythm where once a day we sleep for an extended period of time & wake up for an extended period of time
Define Endogenous Pacemakers
Internal body clocks that regulate our biological rhythms
Define Exogenous Zeitgebers
Externa cues that influence and reset our internal biological clocks.
What is the internal clock that controls our sleep wake cycle and where is it
Suprachiasmatic Nucleus
It is in the hypothalamus - above the optic chiasm where optic nerves cross
Role of SCN in sleep/wake cycle
Regulates the pineal gland which secrete melatonin during the night (less light) to induce sleep
How do the findings of DeCoursey et al. (2000) demonstrate the role of the SCN in the sleep wake cycle
Studied Chipmunks - those with SCN destroyed had sleep/wake cycle disrupted (awake at night) + were attacked by predators
Shows how SCN regulates sleep/wake cycle and without it we can lose our rhythm
What do Michel Siffre suggest about circadian rhythm
Spent 2 months in cave (w/o natural light) so no exogenous zeitgeber for his sleep/wake cycle.
Without natural light his sleep/wake cycle had a rhythm of around 25 hours. He woke and slept at fixed intervals. This suggests that we have an internal biological clock that controls our circadian rhythm.
How does research of Czeisler et al. (1999) add to our understanding of the circadian rhythm
Artificial light is an Exogenous Zeitgeber
Questions the findings of self-isolation studies about the length of their sleep/wake cycle because they had artificial light
How has an understanding of the circadian rhythms helped with the treatment of some illnesses
Chronotherapeutics - Study of how timing affects drug treatments and other interventions
Example: In study with cancer patients, found that when in the day patients are given intravenous medication to kill cancerous cells can affect how effective the medication is and how toxic the side effects are.
