Monthly Archives: October 2002

Mysteries of the Brain Part – 4

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Friends, we have all heard the old saying ” a healthy mind in a healthy body”. Is this really true? Does our mental health affect our physical health? What is the relationship between the brain and the body… the nervous system and the immune system? Today in VERITAS,we explore this relationship.

There are two response systems in our bodies: the Brain’s stress response system and the immune system. The stress response system creates/controls stress resulting from stimulus which occurs both within and outside the body. The immune system kills any external organisms and protects us from disease.
The internal steady state of a body is called homeostasis. This is the state of internal well being. The stress response system and the immune system try to maintain this state. The immune system and the nervous system communicate with each other. One hormone shared by the nervous system and the immune system is the corticotropin-releasing harmone(CRH). This hormone is produced in the brain. When released
the CRH causes the pituitary to release cortisol, the best known stress harmone. Now you must remember that the immune system is an
extremely lethal system and must be controlled. If it is not controlled it can go against the body it protects. The stress harmone cortisol controls the immune system. Also cortisol prevents the release of more CRH by the brain and thus regulates the immune system as well as the stress levels.

Another important link between the nervous system and the immune system are the cytokines. The cytokines are protein molecules that send signals from the body’s immune system to the brain. This communication may be by directly going to the brain or by interacting with nerves as far away as the heart. A typical communication takes milliseconds. Activation of the brain by the cyclokines activates different stress responses
in the brain. The response is aimed at staying away from trouble as long as the body is ill. This is the reason why illness causes us to feel over sleepy or lazy. The body wants to get better before fighting again. The immune system tells the brain that the body is ill and should take care.

Of course what I have outlined above is just a small part of the vast communication that exists between the brain and the immune system. But what is clear is that stress and immunity are related. Stress is the brain’s way of controlling/reducing the effects of the immune system. The immune system and the stress response system control each other from overreacting to things.

So what happens when you get stressed because of work/society? The brain does not know if this stress is caused by illness or by something else. Short term stress is okay but if you are stressed about something for a long term then the brain thinks ” this guy is ill. I am sure the Immune system is going overboard… so lemme control it”. It sends CRH and reduces the immune system. So your immunity is lowered
even though you were stressed because of your “cranky” boss. And you get ill. So stress reduces the immunity of the body.

However very high levels of stress can sometimes increase the immune system for a short time. For example during exams students do not generally fall ill. But soon after exams when the pressure is off the illness occurs. However we must remember that different bodies have different stress thresholds and may react differently. There are several illnesses that can be caused by the break of interaction between the immune system and the nervous system. To give you an example : melancholia is a disease in which the immune system has forgotten to switch off the brain’s stress response system…. the result?
Very little sleep, not a good sense of humour, an over stressed individual.

Take another example: depression is the result of hyperactive immune system. The stress response of the brain is lessened. The person sleeps too much, eats too much and gains weight. studies have shown that people with prolonged stress are more likely to have common cold.

Interesting fact: About 20 % of patients with arthritis show clinical depression. You would think that the depression is because of their severe pain in the joints. But that is not the case! Sometimes the pain in the joints does not coincide with the depression symptoms. The reason for this is this: a disturbance in the body’s internal well being may sometimes manifest in the physical disorder(pain in joints) and sometimes in the mental disorder(depression) and sometimes in both. So if you have to remain healthy you have to take care of both your brain and your immune system.
So any problem inside the body may manifest itself as a physical disease or a mental disease.

Today there is a lot of research going on to see if medicines for the nervous system can be used to cure diseases of the body and if antibiotics can be used to cure mental disorders by influencing the immune system.

kanwar

( The information for this VERITAS has been taken
mainly from the Scientific American article ” The mind
body interaction in disease
” by Sternberg and Gold. Thanks
to Sakharwade for sharing this article with me.

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  Go, wondrous creature! mount where Science guides:
 Go, measure earth, weigh air, and state the tides:
 Instruct the planets in what orbs to run,
 Correct old time and regulate the Sun;

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The Crab Nebula

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In  July 1054 a strange and very large star mysteriously appeared in the sky. The new star was so bright that it could be seen even during the day time. The Chinese astronomers were very excited and maintained an exact record of the star’s dramatic appearance and its eventual disappearance from the sky. The Red Indians were so inspired by the new star that they drew pictures of it in their caves. However no records of
this event have been kept by Indians or the Europeans. Our ancestors may not have seen it because all this happened in the monsoon months of July and August. The Europeans may have chosen to ignore it because it would have gone against their belief that the universe created by God is perfect and the heavens do not change.

       This was a most astonishing event. New stars dont just appear! According to the Chineese the new star gave out intense rays even during the day time and it had a reddish white colour. The star remained visible at evening time for almost a year and then it faded away just as mysteriously as it had arrived.

       This mystery was forgotten for almost 600 years. The invention of the telescope helped astronomers look closely at the site where the mysterious star had appeared. In 1731 the English astronomer Charles Messier observed strings of gas and dust at exactly the same position in the sky. They called it the Crab Nebula( A cloud that looks like a crab). This was the first intergalactic cloud(nebula) to be observed. Astronomers
were fascinated by this strange object and started sudying it with their telescopes.

         In 1939 John Duncan calculated that the crab was expanding and would have have started as a point object about 800 years earlier. A few years later scientists armed with even bigger telescopes observed a much smaller star at the center of the Crab nebula. This star was emitting the most powerful radio waves compared to any other celestial body.

       Today we know that the bright “new” “star” that appeared mysteriously in July 1054 was actually the death of a star. A star almost 50 times larger than our Sun had exploded. This phenomenon is called a Supernova( nova means new). All the mass that this star contained became clouds of dust ( the nebula). And the core of the star turned into a neutron star( a star having no electrons…just neutrons). It emits powerful radio waves. So what happened in the year 1054 was a cataclysmic explosion.

       The explosion took place almost 6500 light years from the earth. So if it was visible during daytime on earth you can imagine its power. If it had happened even as far as 50 light years from earth life on earth would have been destroyed because of the intensity of the radiation

       Everything in the universe is very far from us. Light takes 6500 years from the crab nebula site to reach the earth. So the actal explosion started in the year 5446 BC. The filaments of the nebula are still expanding at the rate of 1000 Kms per second. The diameter of the crab nebula is 6 light years! The pulsar (the small neutron star at the centre) is about 12 Kms across and rotates about its axis at 33 times per sec.

       When we fight with each other we do not realize that the earth is just a small insignificant dust particle in the universe. The universe outside is MUCH MUCH bigger and so many more exciting things happening. There is so much going on…. How can we fight with earh other over insignificant things????

       When everybody is making a face
       and calling each other names
       And the whole world is ajangle and ajar….
       I meditate on interstellar space
       And smoke a mild cigar…. 😉

kanwar

( References: Todays VERITAS has been inspired by the book “Violent Phenomenon in the UNiverse” by Jayant Narlikar. The little poem at the end has been taken from the poem Canopus written by Bert Leston Taylor. )

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 Go, wondrous creature! mount where Science guides:
 Go, measure earth, weigh air, and state the tides:
 Instruct the planets in what orbs to run,
 Correct old time and regulate the Sun;
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Veritas by Kanwarpreet Grewal is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.

The Brachistochrone Problem

 

      You should be very careful when you talk about a scientist named Bernoulli. Because  Bernoulli was not one famous scientist. The Bernoullis  were a family of mathematicians and  scientists.

In three generations the Bernoulli family produced 8 eminent mathematicians. Most of them did not choose mathematics as their profession but “drifted into it inspite of themselves as a dipsomaniac returns to alcohol”(E.T Bell). They fought with each other over mathematics. Once Johannes Bernoulli threw his son out of the house because the son had won a mathematics prize for which the father had also competed! “After all, if rational human beings get excited over a game of cards, why should they not blow up over mathematics which is infinitely more exciting?”(E.T Bell) 🙂

        In the year 1696 Johann Bernoulli challenged the mathematicians of Europe with a problem:”If two points are fixed at random(one at a lower height than the other but not vertically below) then what is the shape of the incline along which a body should slide so that it reaches the other point in the least possible time?” The answer, VERITAS readers is not a straight line! The mathematicians spent six months trying to solve this problem but they all failed. One evening this problem reached the great Newton. Newton had just returned from his duties as the warden of the royal mint. He was tired but not tired enough for mathematics. The problem was solved after dinner and the correct answer was despached anonymously to Bernoulli.

Bernoulli on reading the solution immediately recognised that it was Newton who had solved the problem. He said “one can recognise the lion by the impression of his paws”!

     The problem is known as the brachistochrone(“shortest time”) problem . And the correct answer to the problem is a cycloid. So if the shape of the curve between the two points is a cycloid then the body will take the least time to travel between the two points. See attached file to find what a cycloid looks like.  The cycloid and similar curves were studied extensively by the Bernoillis. They also found that the cycloid is also a tautochrone i.e a body placed at any height on a cycloid would take the same time to come down! See attached figure:

if a body is placed at the highest point A or a point lower than A (near B) the time taken to come to the bottom of the curve under gravity would be the same!

      The branch of mathematics that deals with finding the path of least/most length or least/most time between two points under various conditions is called the calculus of variations. The Bernoullis laid the foundations of this branch of mathematics.

      Now I shall attempt to shock you, VERITAS readers.  There is a principle in Physics called “Fermat’s principle of least time”. According to this principle light travels along a path between two points which takes it least time. Note that this is true even if light has to bend or pass throught objects of different kinds. Light chooses the path that will take the least time! This principle is so deep and fundamental that you can derive the laws of reflection and refraction of light using this principle alone! How much does light bend when it goes into a material such as water. It will take the path that will minimise time and you will know how much it will bend! How does light decide which path to take? Surely light cannot select paths! Is there intention in nature? Does light make decisions? The answer to this question lies deep inside the laws of Quantum Mechanics. Such minimum principles are fundamental in nature and surprise everyone including most Physicists. 

                  Give me to learn each secret cause;

                  Let number’s, figure’s, motion’s laws

                  Reveal’d before me stand;

                  These to great Nature’s scenes apply,

                  And round the globe, and thro’ the sky,

                  Disclose her working hand

                              –Mark Akenside

(Most of the material for this VERITAS has been taken from the book “Men of Mathematics” by ET Bell and the book “Classical Mechanics” by Herbert Goldstein)

 

Kanwar

 

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  Go, wondrous creature! mount where Science guides:                 

  Go, measure earth, weigh air, and state the tides:                 

  Instruct the planets in what orbs to run,                          

  Correct old time and regulate the Sun;                              

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