biological rhythms: circadian rhythms Flashcards
what is a biological rhythm?
it is a change in the body processes or behaviour in response to cyclical changes within the environment. They are influenced by internal body clocks and external changes to the environment.
what is our biological clock?
they are organisms natural timing devices regulating the cycle of circadian rhythms. They are composed of specific molecules that interact with cells throughout the body and nearly every tissue or organism contains biological clocks.
what is a circadian rhythm?
they are physical, mental and behavioural changes that follow a 24 hour cycle. These natural processes respond primarily to dark and light and affect most living things. Chronobiology is the study of sleep cycles.
what is an example of a circadian rhythm?
One type of light-related circadian rhythm is our sleep cycle. This means that our body knows that when it is daytime we are awake, and at night we are asleep.
what is the master clock?
this is the part of the brain that coordinates all the biological clocks in a living thing, keeping the clocks in sync. In humans and vertebrate animals, the master clock is a structure called the SCN. This is part of the hypothalamus and it receives direct input from the eyes.
how does the master clock regulate our sleep cycle?
The master clock helps to regulate our sleep cycle as the period and cryptochrome genes code for proteins that build up in the cells nucleus at night and lessen during the day. Studies into fruit fly’s suggested that these proteins help activate feelings of wakefulness, alertness and sleepiness. However, signals from the environment also effect circadian rhythms such as exposure to light at different times of the day can impact when the body turns on period and cryptochrome genes.
what are the other bodily influences on our sleep cycle?
Circadian rhythms influence important functions such as hormone release, eating habits and digestion and our body temperature. However the most noticeable effect is on our sleep patterns as the SCN controls the production of melatonin which is the hormone that effects our sleep levels. The SCN receives information about incoming light from the optic nerves which relay information from the eyes to the brain, so if they detect less light, the SCN notifies the brain to produce more melatonin causing drowsiness.
what other factors effect our circadian rhythms and what can they cause?
Some factors that effect our circadian rhythms are mutations or changes in certain genes which effect our biological clocks, jet lag or shift work which causes changes in the light-dark schedule, light from electronic devices at night. These changes can cause sleep disorders, obesity, diabetes, depression, bipolar.
how does jet lag effect our circadian rhythm?
Jet lag can effect circadian rhythms as when you travel through different time zones, your biological clock will be different to the local one. Your biological clock will reset but it will happen at a different rate and it often takes a few days for your biological clock to align with a new time zone. Adjusting after ‘gaining’ time may be slightly easier than after ‘losing’ time because the brain adjusts differently in the two situations.
how do researchers investigate circadian rhythms?
Researchers look into circadian rhythms by studying humans and using organisms with similar biological clock genes such as fruit flies and mice. Researchers do these experiments by controlling the subjects environment by altering the light and dark periods. They then look for differences in gene activity and other molecular signals. Scientists may also study organisms with irregular circadian rhythms to identify which genetic components of biological clocks may be broken.
AO3: how is ‘real life application’ a strength to research into circadian rhythms?
