AO1

• Endogenous pacemakers (EP’s)- Internal biological structures that control and regulate the rhythm.
• The most important endogenous pacemaker is the suprachiasmatic nucleus (SCN), which is closely linked to the pineal gland, both of which are influential in maintaining the circadian sleep/wake cycle
• The SCN sends signals to the pineal gland, which leads to an increase in the production of melatonin at night, helping to induce sleep. The SCN and pineal glands work together as endogenous pacemakers; however, their activity is responsive to the external cue of light.
• Exogenous zeitgebers (time givers) (EZ’s)- External environmental factors that influence the rhythm.
• The most important zeitgeber is light, which is responsible for resetting the body clock each day, keeping it on a 24-hour cycle.
• The main endogenous pacemaker in this rhythm is the suprachiasmatic nucleus (SCN). Endogenous pacemakers are mechanisms within the body that govern the internal, biological bodily rhythms
• Babies do not form CR until around 4 months of age ..research m suggests they develop this rhythm due to social cues like eating and fitting in with the families social patterns.