INTELLIGENT DEVELOPMENT 161mone corticotropin. Th is then enters the bloodstream to reach the adre-
nal glands above the kidneys. Th e ste roid hormone cortisol is released
into the bloodstream, followed by aspects of the classic stress response,
such as feelings of alarm, muscle tension, and increased heart rate.
Again, it sounds rather like a straightforward cue- response (or refl ex)
cycle. But there are many other players in the stress- response system. One
is noradrenalin, produced in the locus coeruleus, a small nucleus in the
hindbrain. Th is center is connected with all the primary senses, and also
with cognitive and social activities. Th e noradrenaline is released via
nerve fi bers into numerous parts of the brain in response to perceived
challenge. It promotes a state of excitement and awareness (as well as the
release of corticotropin- releasing hormone from the hypothalamus, as
just mentioned).
Th e other player is adrenalin, which is released from the adrenal cor-
tex following stimulation from nerve branches terminating there, them-
selves being stimulated by fi bers from the locus coeruleus. Together the
hormone interactions produce the classic preparation for “fi ght or fl ight,”
including increased heart and respiratory rates, dilation of arteries to
muscles, constriction of peripheral blood fl ow, release of blood sugar for
energy, increase in blood pressure (to get blood to the muscles), and
suppression of the immune system.
Although superfi cially plausible, therefore, the general stress- response
concept has turned out to be too simplistic. Responses now appear to
be more variable, depending on individual histories and current con-
texts, with diverse psychological and neurological consequences in both
animals and humans. Th ese include emotional dysregulation, panic
attacks, post- traumatic stress disorder, and many other states. Th ey are
further evidence of an intelligent system attempting to learn from the
past to prepare for the future.
In contrast, more congenial conditions, permitting the systems to co-
ordinate as they were evolved to do, fosters great benefi ts for the body as
a whole. As an article in Nature Reviews: Neuroscience explains, integra-
tion “results in the stress instruments producing an orchestrated ‘sym-
phony’ that enables fi ne- tuned responses to diverse challenges.”^18
Research is making it clear that, as for cell metabolism and develop-
ment, there is deeper structure in physiology. As with pro cesses in the cell
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