The two components of the fight or flight response are the neural response and the hormonal response. The neural response is from the activation of the sympathetic nervous system, which is part of the autonomic nervous system, involved with regulation of body organs. The hormonal response is from the activation of the HPA (hypothalamic pituitary adrenal system.
The neural response is from the activation of the sympathetic nervous system. Fear stimulates the amygdala (part of the brain), which then stimulates the locus coeruleus. The locus coeruleus in turn activates the sympathetic nervous system. The sympathetic nervous system stimulates smooth muscles and glands via neural connections. The result is an increase in heart rate, increase in respiration, increase perspiration, decreased motility of the large intestines, increased tension of the muscles, increased pupillary dilation, and increased blood pressure.
The hormonal response comes from the activation of the HPA system. The amygdala senses fear, then the amygdala stimulates the hypothalamus to release corticotropin releasing factor (CRF), which stimulates the pituitary to release adrenocorticotropic hormone (ACTH). ACTH then travels via the bloodstream to the adrenal cortex, which is in the adrenal glands on top of the kidneys. The adrenal cortex then releases cortisol into the blood, which is a “stress” hormone, and is responsible for increasing glucose in the blood and suppressing the immune system. In addition, the adrenal medulla, also located in the adrenal glands, is activated by the sympathetic nervous system, and the adrenal medulla releases adrenaline (epinephrine) and noradrenaline (norepinephrine) into the bloodstream, which are also “stress” hormones. Adrenaline and noradrenaline also participate in the overall fight or flight response, where the body becomes faster, stronger, and more alert. Of note is that noradrenaline is responsible for the increased alertness and vigilance of the fight or flight response.
So the two components of the fight or flight response are the neural response, which communicates with smooth muscles and glands via neural connections, and the hormonal response, which releases the “stress” hormones adrenaline, noradrenaline, and cortisol into the bloodstream. These “stress” hormones travel to other parts of the body that are not innervated by the sympathetic nervous system. So these two components make the body faster, stronger, and vigilant for danger.
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What factors decide whether or not the body fights or flees. Does that make sense? I w ant to know how the body decides which one to do.
Dear Fluffytheunicorn,
The fight or flight response is reflexive at first, bypassing the awareness centers and planning centers of the brain. So when first presented with a danger, the amygdala is triggered and thus sets off the cascade of sympathetic nervous system and HPA axis activation, leading to the preparation of your body to fight or flee. When deciding whether to fight or run, this occurs when the planning centers of your brain, the medial prefrontal cortex, sends inputs to the amygdala to determine the best course of action to get you safely out of danger. Unfortunately, children and adolescents do not have a fully developed prefrontal cortex until they reach their early adult years, so their decisions may seem irrational and they have difficulty controlling their feelings. So the decision to fight or flee is mediated by the prefrontal cortex, involved in planning.
Interestingly, recent research in crickets has found that the release of a chemical from its nerve cells, nitric oxide, helps a cricket to decide that it has lost a fight and needs to run (Stevenson and Rilich, 2015). A chemical message to fight or flee for mammals and humans have yet to be determined.
Reference:
P. Stevenson and J. Rillich. Adding up the odds—Nitric oxide signaling underlies the decision to flee and post-conflict depression of aggression. Science Advances. Published online March 13, 2015
Sincerely,
Dr. Carlo
Explain the blood flow to tissues changes during fight to fight response.
Here is the detailed answer to your question: https://anxietyboss.com/anxiety-forums/418/explain-blood-tissues-changes-during-fight-flight-response
Hi. Dr. Carlo,
I am interested in learning more about this response as it pertains to agricultural animals used for consumption. During the fight or flight response, hormones are released , as you’ve indicated. Their hormone levels are high at the time of death due to fear and stress. How do these chemical changes effect humans who consume the flesh of these animals? Could there be a correlation of human related hormonal and chemical imbalances due to the consumption of animal flesh? -as these animals are killed while in fight or flight mode.
Sounds like a research study for a grad student thesis…need to measure the hormone levels in the animal flesh, then correlate it with the hormone levels in the humans who devour it, before and after.
The locus coeruleus or the hypothalamus activates the sympathetic nervous system? On wikipedia says the hypothalamus but you say the locu coeruleous. Thanks
They both do…look at the diagram.
How to prevent the body from releasing adrenaline through the use of herbs or nutritional supplements
none known- this is more about stress management