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The physiological basis of stress

What goes on inside our bodies when we experience stress? The physiological mechanisms of stress are extremely complex, but they generally involve the work of two systems—the sympathetic nervous system    and the hypothalamic-pituitary-adrenal (HPA) axis    . When a person first perceives something as stressful (Selye’s alarm reaction), the sympathetic nervous system triggers arousal via the release of adrenaline from the adrenal glands. Release of these hormones activates the fight-or-flight responses to stress, such as accelerated heart rate and respiration. At the same time, the HPA axis, which is primarily endocrine in nature, becomes especially active, although it works much more slowly than the sympathetic nervous system. In response to stress, the hypothalamus (one of the limbic structures in the brain) releases corticotrophin-releasing factor, a hormone that causes the pituitary gland to release adrenocorticotropic hormone (ACTH) ( [link] ). The ACTH then activates the adrenal glands to secrete a number of hormones into the bloodstream; an important one is cortisol, which can affect virtually every organ within the body. Cortisol is commonly known as a stress hormone and helps provide that boost of energy when we first encounter a stressor, preparing us to run away or fight. However, sustained elevated levels of cortisol weaken the immune system.

A figure shows an outline of the human body that indicates various parties of the body related to the hypothalamic-pituitary-adrenal axis. The hypothalamus, pituitary gland, and adrenal glands are labeled. There is an arrow from hypothalamus to pituitary gland and another arrow from pituitary gland to adrenal glands. These arrows represent the flow between these organs.
This diagram shows the functioning of the hypothalamic-pituitary-adrenal (HPA) axis. The hypothalamus activates the pituitary gland, which in turn activates the adrenal glands, increasing their secretion of cortisol.

In short bursts, this process can have some favorable effects, such as providing extra energy, improving immune system functioning temporarily, and decreasing pain sensitivity. However, extended release of cortisol—as would happen with prolonged or chronic stress—often comes at a high price. High levels of cortisol have been shown to produce a number of harmful effects. For example, increases in cortisol can significantly weaken our immune system (Glaser&Kiecolt-Glaser, 2005), and high levels are frequently observed among depressed individuals (Geoffroy, Hertzman, Li,&Power, 2013). In summary, a stressful event causes a variety of physiological reactions that activate the adrenal glands, which in turn release epinephrine, norepinephrine, and cortisol. These hormones affect a number of bodily processes in ways that prepare the stressed person to take direct action, but also in ways that may heighten the potential for illness.

When stress is extreme or chronic, it can have profoundly negative consequences. For example, stress often contributes to the development of certain psychological disorders, including post-traumatic stress disorder, major depressive disorder, and other serious psychiatric conditions. Additionally, we noted earlier that stress is linked to the development and progression of a variety of physical illnesses and diseases. For example, researchers in one study found that people injured during the September 11, 2001, World Trade Center disaster or who developed post-traumatic stress symptoms afterward later suffered significantly elevated rates of heart disease (Jordan, Miller-Archie, Cone, Morabia,&Stellman, 2011). Another investigation yielded that self-reported stress symptoms among aging and retired Finnish food industry workers were associated with morbidity 11 years later. This study also predicted the onset of musculoskeletal, nervous system, and endocrine and metabolic disorders (Salonen, Arola, Nygård,&Huhtala, 2008). Another study reported that male South Korean manufacturing employees who reported high levels of work-related stress were more likely to catch the common cold over the next several months than were those employees who reported lower work-related stress levels (Park et al., 2011). Later, you will explore the mechanisms through which stress can produce physical illness and disease.

Summary

Stress is a process whereby an individual perceives and responds to events appraised as overwhelming or threatening to one’s well-being. The scientific study of how stress and emotional factors impact health and well-being is called health psychology, a field devoted to studying the general impact of psychological factors on health. The body’s primary physiological response during stress, the fight-or-flight response, was first identified in the early 20th century by Walter Cannon. The fight-or-flight response involves the coordinated activity of both the sympathetic nervous system and the hypothalamic-pituitary-adrenal (HPA) axis. Hans Selye, a noted endocrinologist, referred to these physiological reactions to stress as part of general adaptation syndrome, which occurs in three stages: alarm reaction (fight-or-flight reactions begin), resistance (the body begins to adapt to continuing stress), and exhaustion (adaptive energy is depleted, and stress begins to take a physical toll).

Personal application question

Think of a time in which you and others you know (family members, friends, and classmates) experienced an event that some viewed as threatening and others viewed as challenging. What were some of the differences in the reactions of those who experienced the event as threatening compared to those who viewed the event as challenging? Why do you think there were differences in how these individuals judged the same event?

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Questions & Answers

How is everyone doing
Lotegeluaki Reply
good.
Cathleen
good
Flora
I didn't know it had this feature. Good, thanks for asking.
Cheriyan
getting better thanks ... how are you ?
Jim
Oh hey
Nikki
Hmm
Nikki
Doing well, thank you!
Amanda
could someone talk about the 4th level of maslow's hierarchy of needs pyramid. thanks
Neelkanth
@Neelkanth , The fourth level depicts self worth. It basically means pride enters one's life later on. Honestly, I don't confirm to the hierarchy much.
Zoya
An example, this a drastic example, : Making an 11 year old kid that has gone through basic conditioning beg for his/her life may be easy when you put a gun to their head.
Zoya
However, when you do so to a man in his late 30's to 40's who has also gone through the same conditioning in his childhood, it may be more difficult to make him beg. This is because he has earned a reputation. Went up the hierarchy
Zoya
when young children speak in short phrases using verbs and nouns,what it is referred to
Simran Reply
how old? generally that's how kids talk isn't it?
Ezra
especially shy ones
Ezra
slang
Emma
what are the social psychology concepts
MICOT Reply
their are about seven main theories... hope someone could help out with main one and their characteristic
Neelkanth
the self concept, social cognition, attribution theory, social influence, group processes, prejudice and discrimination, interpersonal processes, aggression, attitudes and stereotypes.
Deepa
what is different between psychoanalysis, psychopathology?
salma
when do children form oppions
Tasha Reply
they sit in home and play home toys
muhammad
oppions?
Grace
How to know other person
RAGHAV Reply
what is the nature and scope of biopsychology?
Pratibha Reply
working along with neurologists and doctors closely on the field related to brain and nerves
devesh
How can one over come a sleep debt
Andy Reply
how does an algorithm save you time and energy when solving a problem
john Reply
by directing your attention or misdirecting your attention to a particular topic
frederick
can an obsession with blood and Gore be caused by psychological trauma
Dalton Reply
psychological trauma is a bit of a wild card in the case of long term effects. everyone has their own unique experience and I dont see why the example in your question couldn't be a possible manifestation.
Elle
it would be a bigger possibility of this resulting from trauma if this began after you witnessed a violent or gory event. however this often comes from the amount of violence and gore we are exposed to through social media, the news, and fictional material like books, movies and video games.
andrina
how can the bipolar and mood disorder can prevent?
Shana Reply
Control stress. Stress is a major bipolar trigger. ... If you would control stress you will simply feel good ....if you want to know more about this DM @shana mae
KhaLid
That brings us to the next question.. How do we actually control stress in an effective way?
Looney
well for me mindfulness meditation techniques are very much effective for coping with stress ....
KhaLid
please what are the major things I need to know now in psychology,because I'm a new student of psychology.
Godwin
Godwin if it is your begining in this field you should first clear some concepts like what is psychology it's etymology , structuralism,functionalism , behaviourism and many other perspectives .....
KhaLid
first of all are you studying in psychology or working as a psychologist
muhammad
studying Sir
Godwin
Thank you Sir Khalid.
Godwin
Muhammad Akram Both ☺️
KhaLid
Far too often, you can't control stress just like that on your own . And it will affect you On subconscious level . When it comes to meditation it's something to take seriously and best to be taught by professional.
Kira
I know there are many other ways but I found this one at my own Kira Emerala!
KhaLid
Hi friends
RAJABU
it can't be extracted I'll tell u that much
Shawnte
someone who study psychology here need help ? anyone ?
khawla
Can I ask for tips when you have no motivation and can't focus with your studies?
Jhea
For Shana, I'm sorry, I can't answer your concern at the moment, because I'm still studying about the basics of psychology 😬
Daydreaming
do meditation, start learning few pages initially n understand before moving to another topic
mini
play a sport of your choice for half an hour or listen to your fav music, develop your positive outlook towards life
mini
learn to balance work play study
mini
n health
mini
I'm struggling with BPD cptsd major anxiety disorders and going to college for a psychology degree. trying to maintain motivation is difficult. what can I do?
Sarah
I already meditate take my meds use biofeedback and several other things
Sarah
As a student, it is normal to lose motivation during college life but look at the long term goal. What do you want to achieve at the end? Divide it into small achieveable goals. Once you achieve it, focus on 2nd small goal. Last thing, it's okay to ask for help when needed. We are all in a journey.
mehdi
what's your friend's circle
muhammad
khawla saadouni yes how can I help you ?
KhaLid
Sarah you need CBT it will be effective on that what you are experiencing !!
KhaLid
implicit memory are those type of memories which can be written without any unconsciousness
Aayu Reply
m interested in this research...
Arnav
me too plz I am suffering from depression so v forgetful which has ruined my life
Sins
yes plank youth
Shawnte
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Shawnte
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Shawnte
sins saintly do you need any help regarding how to cope up ?
KhaLid
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Shawnte
yes
Shawnte
what do you mean by sensory memory
Aayu Reply
sensory memory simply is an automatic response, not under conscious control. It deals with the input from the senses. 
KhaLid
what is the name of a person who introduction the techniques of factors analysis in intelligence
JobJoy Reply
what is associated with the developmental
JobJoy
lifelong spiritual advice
Zach Reply
Can you define spiritual Zach?
Emely
Are teeth part of our minds?
Kamil
who introduced the technique of factor analysis in intelligence
JobJoy Reply
Spearman's (1904)
Stephen
apart from Spearmans 1904 who again
JobJoy
Howard Garner
Komal

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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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