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If we have biological rhythms, then is there some sort of biological clock ? In the brain, the hypothalamus, which lies above the pituitary gland, is a main center of homeostasis. Homeostasis is the tendency to maintain a balance, or optimal level, within a biological system.

The brain’s clock mechanism is located in an area of the hypothalamus known as the suprachiasmatic nucleus (SCN)    . The axons of light-sensitive neurons in the retina provide information to the SCN based on the amount of light present, allowing this internal clock to be synchronized with the outside world (Klein, Moore,&Reppert, 1991; Welsh, Takahashi,&Kay, 2010) ( [link] ).

In this graphic, the outline of a person’s head facing left is situated to the right of a picture of the sun, which is labeled ”light” with an arrow pointing to a location in the brain where light input is processed. Inside the head is an illustration of a brain with the following parts’ locations identified: Suprachiasmatic nucleus (SCN), Hypothalamus, Pituitary gland, Pineal gland, and Output rhythms: Physiology and Behavior.
The suprachiasmatic nucleus (SCN) serves as the brain’s clock mechanism. The clock sets itself with light information received through projections from the retina.

Problems with circadian rhythms

Generally, and for most people, our circadian cycles are aligned with the outside world. For example, most people sleep during the night and are awake during the day. One important regulator of sleep-wake cycles is the hormone melatonin    . The pineal gland    , an endocrine structure located inside the brain that releases melatonin, is thought to be involved in the regulation of various biological rhythms and of the immune system during sleep (Hardeland, Pandi-Perumal,&Cardinali, 2006). Melatonin release is stimulated by darkness and inhibited by light.

There are individual differences with regards to our sleep-wake cycle. For instance, some people would say they are morning people, while others would consider themselves to be night owls. These individual differences in circadian patterns of activity are known as a person’s chronotype, and research demonstrates that morning larks and night owls differ with regard to sleep regulation (Taillard, Philip, Coste, Sagaspe,&Bioulac, 2003). Sleep regulation refers to the brain’s control of switching between sleep and wakefulness as well as coordinating this cycle with the outside world.

Disruptions of normal sleep

Whether lark, owl, or somewhere in between, there are situations in which a person’s circadian clock gets out of synchrony with the external environment. One way that this happens involves traveling across multiple time zones. When we do this, we often experience jet lag. Jet lag is a collection of symptoms that results from the mismatch between our internal circadian cycles and our environment. These symptoms include fatigue, sluggishness, irritability, and insomnia    (i.e., a consistent difficulty in falling or staying asleep for at least three nights a week over a month’s time) (Roth, 2007).

Individuals who do rotating shift work are also likely to experience disruptions in circadian cycles. Rotating shift work refers to a work schedule that changes from early to late on a daily or weekly basis. For example, a person may work from 7:00 a.m. to 3:00 p.m. on Monday, 3:00 a.m. to 11:00 a.m. on Tuesday, and 11:00 a.m. to 7:00 p.m. on Wednesday. In such instances, the individual’s schedule changes so frequently that it becomes difficult for a normal circadian rhythm to be maintained. This often results in sleeping problems, and it can lead to signs of depression and anxiety. These kinds of schedules are common for individuals working in health care professions and service industries, and they are associated with persistent feelings of exhaustion and agitation that can make someone more prone to making mistakes on the job (Gold et al., 1992; Presser, 1995).

Questions & Answers

encoding is the last step in memory stracture
FARWA Reply
crow and angle have feathers and can fly " it is a connective concept
FARWA
my mother always take decision based on reasoning ; she is practicng realistic thinking .
FARWA
all human are mortal is a formal concept
FARWA
sparrow is a best prototype of reptile
FARWA
echoic memory reflect humans visual system
FARWA Reply
getting the information back from stored area of brain is called retrieval
FARWA
no , echoic memory reflect upon things you hear , that's Iconic memory which deals with visual information
Nancy
I'll be studying psychology soon. Where do I start?
Jane Reply
I would start by learning basic terminology and definitions cause there's a lot of it and learning the different concepts behind psychology and there meanings and there use then go onto introduction into psychology
why is psychology a science?
Godslove Reply
it's a social science
Alex
what we define as science is a systematic arrangement of knowledge based on experimental and observational data.so psychology is a science. as for what kind of science it is depends on how and what information are you using in your approach towards understanding the said data and to what conclusion.
imirror
depending on your approach and understanding Psychology can classify as medical or social science like anthropology
imirror
your friend is under stress because she has not prepared well for the examination what strategies would you suggest her? express in 100 or 150 words
Masi Reply
hello
Masi
yess
dcs
where on the disorders does paranoid thought come in?
Hot Reply
hot shots will give you paranoid thoughts
Kimberly
Kimberly 😂😆😂 yes hot shots will give you paranoid thoughts
Brandon
what compound motivation is attention extension
Gauri Reply
what is psychology
Drishti Reply
The scientific study of the mind
Gina
scientific study of mind and behaviour
Siva
...
Saeed
Scientific study of mind soul behaviour and experiences
Ayush
scientific srtudy of behaviour and cognitive processes
Reshmi
Apply social psychology on real life in Nigerian universities campus
tyosaa Reply
what is the meaning of an idiosyncratic pattern
Krystle Reply
I am here for the first time just here to learn...
michael Reply
hi I'm new on here first time
Lisa
hello
GOPAL
hi,am new here
jennifer
what is this group all about
jennifer
Suppose an individual with OCD experiences obsessive thoughts about germs, contamination, and disease whenever she encounters a doorknob. What might have constituted a viable unconditioned stimulus? 
la Reply
What are factors that influence learning?
Enos Reply
Environment Heredity(I am not sure about heredity)
Tusita
Helpful. .. thanks
Enos
Sure, anytime
Tusita
I have other questions also
Enos
Based on the factors affecting learning, how do we improve learning
Enos
I think that addressing that everyone learns in their own time
James
Peer group influence can also be another reason
Sorie
Also knowing what's going on at home. what pressure are the parents putting on them.
James
am I close or no
James
also is there a lack of care? going one more step. with peer groups do an activity that shows how much they have in common
James
I think one's society has a big role to play in determining what/when & how he/she learns.
BECHEM
multiple reasons at different stages. at the earliest stages of development in a child is behaviour of people around. A baby starts learning basic social expressions and actions by mimicking the people around it. further social and cultural practices enforces learning and behaviour
imirror
from need to nutrition everything affect development and learning when choosing on a single factor of influence it is necessary to keep these other factors in the mind as environment around people is very plastic and flexible and there are many variables playing active role
imirror
social interaction is surely a big influence hence can be used to improve learning.
imirror
to encourage learning it is important to establish curiosity and notion of possibility for more perspectives habit of questioning possibilities and cause and effect in a great way to encourage learning in my opinion. language is another important factor
imirror
under what schedule of reinforcement do animals learn from ?
Phelisa Reply
the role of emotional intelligence in a courtship behavior
Caren Reply
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Source:  OpenStax, Psychology. OpenStax CNX. Feb 03, 2015 Download for free at https://legacy.cnx.org/content/col11629/1.5
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