control of biological rhythms Flashcards
what are endogenous pacemakers?
they are internal or inbuilt body clocks
what are exogeneous zeitgebers
environmental/ external cues that play a role in regulating biological rhythms. E.g light, food, etc.
what do mammals have for their endogenous pacemaker
a tiny cluster of nerve cells called the suprachiasmatic nucleus
where is the suprachiasmatic nucleus found?
in the hypothalamus just above the optic chiasm
what inbuilt firing pattern does the suprachiasmatic nucleus have?
it has an inbuilt circadian rhythmic pattern
where does the pineal gland receive messages from?
the suprachiasmatic nucleus
what happens once the the suprachiasmatic nucleus has sent signals to the pineal gland?
it increases its production of melatonin
how does melatonin induce sleep?
it inhibits the brains mechanisms that promote wakefulness
how do endogenous pacemakers change during an average persons life span?
IN babies their sleep wake cycle is much shorter, in adolescents it is delayed and in adults eight hours of sleep and in old age the cycle is shortened again.
