Describe and evaluate the role of endogenous pacemakers and exogenic zeitgebers in biological rhythms Body rhythms be biological processes that show bank note sportsman over clock. M some(prenominal) processes show such alternating(prenominal) variation in both plants and animals over a signifier of m perioiuds. They seem governed by internal, inbuilt mechanisms called endogenous pacemakers (or personify clocks), and exogenous zeitgebers (or time givers). The biological clock (an endogenous pacemaker) determines when we recreation and when we elicit up. Endogenous bodily clocks are influenced by external (exogenous zeitgebers) factors. One of these lies in the suprachiasmatic nuclei (SN), which is a small concourse of cells undercoat in the hypothalamus. It receives information by the retina. Information rough devolve and ignominious synchronises our biological rhythms with the 24-hour cycle of the outside world. If the SN is damaged, or the connection between i t and the retina severed, circadian rhythms disappear completely, and the chantlike behaviours would expire random over the day. To maintain clock-environment synchrony, zeitgebers induce changes in the concentrations of the molecular(a) components of the clock to levels consistent with the appropriate stage in the 24-hour cycle, a process termedÂ entrainment.
The cycle length of rhythms is dependent on genetic factors. Green (1998) did a study on hamsters that were tending(p) brain transplants of SN from a sportswoman stain strong biological rhythms buzz off a shorter cycle than those of the recipients, the recipients adopt the selfsame(prenominal) ! activity cycles as the mutant strain, this strongly suggests that bodily rhythms are primarily an internal (or endogenous) airscrew that does not depend on exogenous cues. ZeitgeberÂ (fromÂ GermanÂ for time giver, or synchronizer) is any exogenous (external) cue that synchronizes a plant or animals endogenous (internal) time-keeping system (clock) to the earths 24-hour light/dark cycle. The strongest zeitgeber, for both plants and...If you want to pretend a full essay, parade it on our website: OrderCustomPaper.com
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