PDC Test - The Biology of Stress
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The Biology of Stress
by Renée Cohen
Whether you’re racing the clock to perfect an expedited transcript, sitting amidst rush hour traffic’s exhaust fumes or facing any number of modern life’s challenges, you are under stress. We have all experienced stress, and some of us are painfully familiar with it. While a certain degree of physical and emotional stress can be perfectly healthy, repetitive and constant stress can seriously damage our bodies on microscopic levels and on the larger muscular and skeletal levels.
Luckily, the bulk of our stress can be minimized if it is regarded as a maintenance issue, like teeth brushing, nail clipping or weight management. As with most other types of body maintenance, simple and consistent preventative self-care can keep us happier and healthier than if we ignore our symptoms of excessive stress. Having an indepth understanding of the biology of stress may assist us in this routine management of stress and lead us to improved physical and emotional health.
To most of us, it is abundantly clear that excessive stress can cause personal problems, such as irritability, fatigue, anxiety and despair. On a smaller scale, we probably recall instances from life when stress has caused headaches, muscle tension, digestive problems and increased vulnerability to infections and viruses. In fact, all of these symptoms of stress are grounded in the chemistry of our bodies, which changes when our brains recognize a situation as stressful, when the environment challenges the body’s defenses.
Most of this body chemistry is triggered by the adrenal glands, specifically the adrenal medulla. The adrenal medulla is the organ that secretes the hormone epinephrine, which is more commonly known as adrenaline. Epinephrine, a catecholamine compound, is secreted by the adrenal medulla as a response to any sort of stress, including discomfort and danger, or any anticipation of discomfort. The adrenal medulla is literally where the “fight or flight” instinct comes from in humans.
As epinephrine is delivered by the bloodstream into the receptor sites of cells, the body makes every effort to supply blood to the brain, heart and skeletal muscles. This extra blood, which carries oxygen and little energy packets of glucose and fatty acids from various muscles and the liver, gives the body an extra boost that will help it fight off or escape the danger intelligently and quickly.
On a larger scale, the rest of the body’s muscles are working hard to relieve the body of the stress it feels. Muscles throughout the body contract for a variety of purposes. (This may be why your neck and back get tense when you are under stress.) Some muscles contract in order to increase the intensity
of the heartbeat rate and stroke. This, of course, will lead to quicker distribution of blood throughout the body so that the most important “fight or flight” cells in the brain, heart and skeletal muscles get the oxygen and energy they need. While this is great in the short term, you can imagine that over a prolonged period of time, this elevated intensity of heart rate could lead to an increased risk of coronary disease. In fact, it does just that. High blood pressure, heart attacks and other coronary problems are all associated with intense stress over a long period of time.
Another way that the body responds to epinephrine’s stress alarm is to trigger smooth muscle contraction. The purpose of this is to take blood away from the parts of the body that are not directly
concerned with fighting or fleeing the stressful situation. Thus, blood from the skin, gut and kidneys will all move into the heart, brain and skeletal muscles. Smooth muscles are found mainly in the walls of hollow organs, like blood vessels and digestive organs. While smooth muscles cannot contract as tightly as the skeletal muscles (which help us run, swim, stand, etc.), they can contract over long distances. Since it is the smooth muscles that push food through our digestive system, it is not hard to imagine how a release of epinephrine can indirectly cause a cramp or other discomfort in the digestive process. In the short term of overcoming an immediate threat, such discomfort might not be a problem. If the body is routinely stressed, however, the groundwork for ulcers and other smooth muscle ailments
is laid while the body repeatedly tells the smooth muscles to do work related to overcoming stress, rather than its regular functions.
Aside from all of these blood diversions and chemical deliveries that occur as a body reacts to the brain’s stress, the immune system is compromised too. White blood cell production is suppressed by other panic-related hormones. Ultimately, when the brain reacts to the outside world by panicking, it trips a chemical alarm, epinephrine, which demands a full body response, even if the full body is not endangered.
Now, take a moment to visualize the effect of that alarm. Imagine a company with workers split between two buildings. About every half-hour, in Building A, someone trips the fire alarm and all
of the workers must go outside forsafety. The first few times this happens, the fresh air and short walk outside might be a welcome relief to these workers. After a few times, however, the alarm would start to hurt the production of the company because so much attention and energy gets diverted into responding to the alarm.
In your body, stress is that alarm. Every time your brain panics at some outside stimuli, you trip that alarm again, and every cell in your body must stop what it was doing to respond. In Building B of the same company, the workers are involved in much less activity because they are not constantly running
up and down stairs to respond to the alarm. Then the question becomes how much more are they accomplishing? Theoretically, by measuring their increased productivity, we may be able to get an idea of how stress affects the lives of our work force.
A few deep breaths to oxygenate the blood and a few seconds of stretching tense muscles will relieve some degree of stress immediately. So when you notice yourself becoming stressed, i.e., entering
Building A, just apply these simple techniques and switch to Building B, where less anxiety and a more relaxed lifestyle exists.
Renée Cohen, BA, RPR, is a JCR Contributing Editor.
Campbell, N., Ed. Biology. Redwood City, The Benjamin/Cummings Publishing Co.: 1993.
Pough, F. Vertebrate Life. Upper Saddle River, Prentice Hall: 1999.
The Boston Women’s Health Book Collective. Our Bodies, Ourselves.New York, Touchstone Press: 1992.
1. Repetitive stress can damage a person’s skeletal system, muscular system and circulatory system.
2. Stress can oftentimes be managed by changing one’s outlook on a situation; e.g., by bringing humor into a situation.
3. Stress management is an activity that is best saved for periodic vacations.
4. Making a conscious decision to remain calm in a stressful situation can prevent a temporary change in body chemistry.
5. The “fight or flight” instinct can be traced to a physical location in human biology.
6. Catecholamines are:
a. made up of hydrogen and zinc
b. glucose and fatty acids
d. adrenal glands
7. Skeletal muscles are the muscles that:
a. make up our bones
b. are stretched between the rib cage and pelvis to cradle the digestive tract
c. line digestive organs
d. aid in locomotion
8. Under stress, the brain gets ______blood.
a. the same amount of
c. slightly less
d. dramatically less
9. Heart problems are often associated with a long-term stressful lifestyle.
10. When stressed, the body diverts blood and oxygen to all of the following, except:
d. skeletal muscles
11. Adrenaline is also known as:
a. adrenal medulla
c. fatty acid
12. Smooth muscles:
a. aid with locomotion
b. line the digestive organ walls
c. act as receptor sites
d. release hormones
13. The release of epinephrine is analogous to:
a. a fire alarm
b. loud rock music
d. pleasure sensation
14. In an emergency, _________ helps the body ignore physical pain.
d. smooth muscle tissues
15. Deep breaths relieve stress by:
a. releasing adrenaline
b. oxygenating the blood
c. diverting glucose
d. creating water molecules
16. Stress can cause all of these except:
b. muscle tension
17. The release of epinephrine causes the body’s chemistry to:
a. speed up
b. slow down
c. remain constant
d. release receptor cells
18. Blood loss from the kidneys during a stressful situation can be attributed to:
b. release of epinephrine
d. smooth muscle functions
19. The immune system can be compromised due to:
a. phases of the moon
b. tidal changes
d. excessive sunlight
20. The “fight or flight” instinct is present in:
c. the food chain
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