Discuss the role of endogenous pacemakers in the control of one or more biological rhythms. Endogenous pacemakers are internal biological clocks that manage our rhythms. In humans, the main biological clock is in the suprachiasmatic nucleus (SCN) which is located in the hypothalamus. This controls circadian rhythms. Before the 1920’s, it was assumed that the circadian sleep wake cycle was controlled by external factors, however post 1920’s, it was suggested that biological rhythms are controlled by an internal clock (endogenous pacemaker).
Endogenous pacemakers are body clocks that are internal to our biological systems, the most important being the superchiasmatic nucleus (SCN) which is sensitive to light and receives information via the optic nerve and send this info to the pineal gland, which controls the production of melatonin. Melatonin is vital to the sleep-wake cycle because the hormone induces sleep by inhibiting the brain mechanisms that promote wakefulness. Circadian rhythms are also controlled by exogenous zeitgebers, which are external factors that give an indication of time e.g. daylight, therefore controlling the biological rhythm to be in time with the world. Research has been conducted into the role of endogenous pacemakers by removing external cues from participants by using temporal isolation methods and allowing the free-running biological clock to run unaffected.
There are two ways of generating biological rhythms. These are Exogenous Zeitgebers and Endogenous Pacemakers. Endogenous pacemakers and Exogenous Zeitgebers can manipulate the various bodily rhythms, and have particular effects on the sleep / week cycle in the circadian rhythm. Endogenous pacemakers are separate and distinct internal rhythms that affect the bodily rhythms they are also known as internal biological clocks. Examples of this would be core body temperature, sleep-wake cycle.
Abnormal or radical behavior could therefore “be explained by hereditary factors in combination with poor environmental conditions” (Oreland, Leppert, Hallman, Lindström, Nilsson, K., Sjöberg, R., …Öhrvik, J., 2006). There are two key components in serotonin regulation within the brain, an enzyme, monoamine oxidase A (MAO-A) and the serotonin transporter protein (5-HTT/SLC6A4), which transports the neurotransmitter serotonin from synapses to presynaptic neuron. Functional “variations in the promoter regions allow for division of both these genes into a short and a long allele” (Oreland et al., 2006) proven to exert low and high transcriptional activities, respectively (as cited in Sabol, Hu, & Hamer, 1998; as cited in Lesch, Bengel, Heils, Sabol, Greenberg, Benjamin, … Murphy, 1996). Transcription factor AP-2β has been suggested to influence brain
Describe and evaluate the role of the endogenous pacemakers (25 marks) It is argued that biorhythms such as the release of hormones from the pituitary gland, the daily rise and fall in body temperature and the sleep wake cycle are underpinned by some form of ‘body clock’ situated somewhere in the brain. Psychologists have been attempting to agree upon the extent to which this clock should be seen as a free running mechanism or one which is entrained and regulated by factors such as light and dark and others exogenous zeitgebers or time givers such as social routines of others and man-made clocks. It is thought that one of the body’s most important clocks might be situated in the suprachiasmatic nucleus (SCN), a tiny cluster of nerve cells located within the hypothalamus. This SCN is linked to the optic nerve by a thin tuft of nerve fibres which breaks off just above the optic chiasm and this provides a direct link with light levels in the outside world. This is important as it provides circumstantial evidence that the body clock is regulated by the outside world.
These biological factors are said to determine an individual’s development and characteristics . the ability to speak a first language are thought to be due to an in progress genetic inheritance. Genes provide the instructions for structuring amino acids which in turn influence the proteins within our body cells. Genes process the chemical basis of our biology. Depending on the genes we inherit and the environmental influences we are exposed to, we will act apon a situation differently.
It is released by one nerve ending also known as synapses, and is picked up by another nerve ending. After a message is sent, enzymes in the brain clean the serotonin out of the synapses. C. Main Idea: Patients with OCD have damaged receptor sites and is blocked to prevent sertonin to function potentially. D. Big Point: As Medline Plus explains, on September 25, 2007, recent data shows, that about 7 millions Americans are diagnose with OCD. About the age of 20 to 30 is when the symptoms are noticed by the abnormalities in the brain.
They then discovered that the microbe, code named "Andromeda", mutates with each growth cycle, changing its biologic properties. The scientists learn that Andromeda grows only within a narrow pH range; in a too-acid or too-basic growth medium, it will not multiply — Andromeda's pH range is 7.39–7.43, like that of human blood. That is why Jackson and Ritter survived: both had abnormal blood pH. Before they could learn more, the
One explanation of forgetting from short term memory is called trace decay which assumes that memories leave a trace in the brain. Hebb (1949) called this trace an engram, and suggested that an engram occurs when a group of nerve cells (neurons) in the brain excite and stimulate one another. This engram is very delicate and liable to disruption. Thus, a trace refers to the physical representation of information in the brain – it is some form of physical and/or chemical change in the nervous system/brain. Trace decay theory states forgetting occurs as a result of the automatic decay or fading of this memory trace in the brain.
‘Time and the Conways’ by John Boynton Priestley ‘Time and the Conways’ illustrates J. W. Dunne's theory of Time from his book ‘An Experiment with Time’. Why did Dunne’s ideas interest Priestley? Dunne proposed multiple selves and streams of time: Observer 1, our everyday self, lives in Time 1: linear chronological time. Observer 2 is another self operating in four dimensions (Time 2) who can see Observer 1′s future and past. Above all, Observer 2 comes to the fore when Observer 1 is asleep, hence precognitive dreams which seem to bring the future into the present.