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Q: shock to the organism ( Answered 5 out of 5 stars,   0 Comments )
Subject: shock to the organism
Category: Miscellaneous
Asked by: qpet-ga
List Price: $20.00
Posted: 23 Mar 2003 21:58 PST
Expires: 22 Apr 2003 22:58 PDT
Question ID: 180168
What happens when the human organism goes into shock? What is the
explanation from an evolutionary viewpoint?

Request for Question Clarification by pinkfreud-ga on 24 Mar 2003 07:56 PST

I've been working on this question, but I'm not sure what is meant by
"What is the explanation from an evolutionary viewpoint?"

Do you require specific data discussing the evolutionary history of
shock, or would it be satisfactory to describe the ways in which shock
can enhance the likelihood of an individual's survival?


Clarification of Question by qpet-ga on 24 Mar 2003 10:09 PST
Hi pinkfreud
It would be satisfactory to describe the ways in which shock
can enhance the likelihood of an individual's survival!
Subject: Re: shock to the organism
Answered By: pinkfreud-ga on 24 Mar 2003 11:59 PST
Rated:5 out of 5 stars
We'll start with a look at the medical meaning of the term shock.

The first clinical definition of shock was put forth in the 1800s by
John Collins Warren, who described shock as a "momentary pause in the
act of death." Samuel Gross continued this concept in 1872, calling
shock a "rude unhinging of the machinery of life."

American Association of Critical-Care Nurses

Shock (acute stress reaction) is not a disease in itself. It is a
clinical condition characterized by symptoms that arise when cardiac
output is insufficient to fill the arteries with blood under enough
pressure to provide an adequate blood supply to the organs and

Wilderness Survival 

Shock is the slowing of blood flow to the vital organs (brain, lungs,
heart, kidneys and others). Shock occurs when blood pressure and flow
are not strong enough to force blood through to the vital organs...
The clinical term is as defined above and differs from common,
non-medical usage of the term 'shock'. For example, when a person is
unexpectedly given tragic news, such as the death of a loved one, we
often say that person 'is in a state of shock.' This state of mental
anguish, disbelief and temporary confusion is very different and much
less serious than the medical definition of shock.

Society of Critical Care Medicine

Here is an article that describes different kinds of shock (including
haemorrhagic shock, cardiogenic shock, neurogenic shock, and septic

Santa Chiara Hospital

Another page describing the various kinds of shock:

This emergency medicine site offers a concise description of the
symptoms which characterize shock:

Definition of shock: 
Tachycardia; altered level of consciousness; weak central pulses; weak
or absent peripheral pulses; prolonged capillary refill (> 4 seconds);
Late signs of shock: 
Bradycardia; hypotension; irregular respirations.

County of Sacramento Emergency Medical Services

Shock greatly reduces bloodflow to the body's tissues. This can result
in cellular damage that leads to death, which leads one to wonder how
the phenomenon of shock has persisted through generation after
generation of natural selection.

One explanation is that our ancestors experienced shock primarily in
reaction to catastrophic injuries, particularly injuries that involved
great loss of blood. A condition of shock helps to reduce blood loss,
and protecting blood volume appears to be a survival mechanism, even
if that protection itself may put the body at risk. Here's a good
description of the bodily changes that occur in hypovolemic shock that
occurs as a result of a sudden, massive loss of blood:

The human body responds to acute hemorrhage by activating 4 major
physiologic systems: the hematologic, cardiovascular, renal, and
neuroendocrine systems. The hematologic system responds to an acute
severe blood loss by activating the coagulation cascade and
contracting the bleeding vessels... The cardiovascular system
initially responds to hypovolemic shock by increasing the heart rate,
increasing myocardial contractility, and constricting peripheral blood
vessels... The cardiovascular system also responds by redistributing
blood to the brain, heart, and kidneys and away from skin, muscle, and
GI tract. The renal system responds to hemorrhagic shock by
stimulating an increase in renin secretion from the juxtaglomerular
apparatus. Renin converts angiotensinogen to angiotensin I, which
subsequently is converted to angiotensin II by the lungs and liver...
The neuroendocrine system responds to hemorrhagic shock by causing an
increase in circulating antidiuretic hormone (ADH)... These intricate
mechanisms are effective in maintaining vital organ perfusion in
severe blood loss.


Another theory on the evolutionary value of shock was given to me by a
Professor of Biology at the University of Tulsa, who believes that
shock falls into the same category as near-death experiences: it helps
to induce a state of calm and acceptance in the individual at a time
when fear and panic might eliminate any chance of surviving. And the
fact is that, although shock is an extremely serious medical condition
which can result in death, there are nevertheless some survivors, even
in areas of the world where modern medicine is unknown.

Search terms used:

"definition of shock"
"human body" + "shock"
"traumatic shock"
"survival benefit" + "shock"
"evolutionary benefit" + "shock"

Please request clarification if it is needed. As always, I am more
than willing to focus my research to target your specific

Best regards,
qpet-ga rated this answer:5 out of 5 stars
Simple and complet, Thank you!

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