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More specifically, would this heighten or accelerate the fight/flight response a person may have? Or would it make little difference?

In the past I had come across rare stories where a person was able to achieve superhuman feat during emergencies (such as lifting a car just enough to allow a trapped uncle to escape). I am looking for a way to enable these to be more common for this particular race by enhancing that fight/flight response, and wondered if allowing faster distribution of adrenaline and noradrenaline via the heart would do the trick.

Thank you in advance.

Update: The general consensus from the responses received thus far is that moving the adrenal glands towards the heart will not help me in enhancing the fight/flight response, instead I should consider enhancing the nervous systems and neurons.

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  • $\begingroup$ Hello and welcome to WorldBuilding.SE! This question looks interesting, but also pretty short. While this is not necessarily a bad thing I think your question would benefit from a little more elaboration. Do you want to change anything else in the human body? For example: is the heart in your case the organ producing the adrenaline or does the adrenaline first have to go from the kidney to the heart before being emitted there? What is your idea of what will happen and why are you unsure about this? $\endgroup$ – Sec SE - clear Monica's name Feb 26 '17 at 22:08
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    $\begingroup$ Hello Secespitus, thank you for the welcome! In the past I had come across rare stories where a person was able to achieve superhuman feat during emergencies (such as lifting a car just enough to allow a trapped uncle to escape). I am looking for a way to enable these to be more common for this particular race by enhancing that fight/flight response, and wondered if allowing faster distribution of adrenaline and noradrenaline via the heart would do the trick. $\endgroup$ – DodgeNDive Feb 26 '17 at 22:32
  • $\begingroup$ That's a nice backstory and we appreciate these here. It would be nice if you could add your comment into your question to provide a little more context. Just hit the edit-Button under your question. $\endgroup$ – Sec SE - clear Monica's name Feb 26 '17 at 22:44
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The kidney gets 10-20% of total body blood flow each pass and the adrenals dump into the same outflow vein. From there the products and venous blood go back to the heart via the vena cava, thru the lungs then back out the other side as arterial blood. I don't think it would make much difference if the adrenal products joined the venous blood closer to the heart.

If you had the adrenal output directly into arterial blood right after it left the heart it would probably take action 3-5 seconds faster. It would be hard for adrenals to do that because they would need to overcome the arterial pressure to add their products.

Thiking a little further on this, an adrenal that emptied in the left atrium would get those few seconds and would not have to overcome high arterial pressures. The left atrium actually does make some hormones but I think it has more to do with its ability to sense blood volume status that some speed bonus.

Overall, communicating by blood borne hormones is sort of a relic. Kind of like snail mail in the internet age. It is nice if you are an organism that does not have nerves, or if you want a sustained signal, or some signal that all parts of the body will perceive. If you want speed you need to communicate via nerves.

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    $\begingroup$ Vasoconstriction in peripherals is probably more important to the system, in fact, so this would likely slow reactions due to the delay in efficiency buildup for pumping. The heart rate is only indirectly affected by adrenaline, after all. The body can and does regulate heart rate up when risks are noticed. It doesn't wait for adrenaline to circulate to beat faster. $\endgroup$ – The Nate Feb 27 '17 at 0:32
  • $\begingroup$ Damn backward compatibility is slowing our evolution! $\endgroup$ – PTwr Feb 27 '17 at 20:57
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First, the adrenal glands do a bit more than just producing adrenaline. The hormones produced in the adrenal cortex help to regulate pressure and electrolyte balance in the blood, and they produce metabolic precursors to sex hormones (testosterone, estrogen, etc).

Secondly, the adrenal glands have a pretty good blood supply, including a direct connection to the aorta, the largest artery in the body coming directly off the left ventricle.

Since the adrenal glands are doing a lot more than just adrenaline, there might be a good reason they are attached to the kidneys and not the heart. For example, electrolyte management is a primary job of the kidneys as well, and the proximity may help the two work together. Then, given that the adrenal glands are getting a nearly direct blood supply from the heart, it doesn't seem like moving them is likely to do what you want.

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