Tuesday, August 28, 2012

Taming the Mind

Recently, a mobile, one-ton nuclear powered science lab safely landed on the surface of Mars. This miracle of modern science has started sending data to receiving stations earth which is over 150 million miles away. This surely is one of the great achievements of the human mind. Mars is thought to have been a planet with plentiful water billions of years ago, today it is a dry, dusty and desolate world making human inhabitation practically impossible. If humans were to go to Mars, they would need a very robust space suit to protect against lethal radiation, lack of oxygen and extremes of temperature.

We don’t however have to land on Mars to consider ourselves space travellers. We inhabit a spherical globe we call Earth, that is hurtling through space at a speed that would cover the distance between the Earth and its moon in about 4 hours. Our awareness of the concept of life is limited to the time between the metaphorical curtain raising up heralding our birth and the curtain falling down signalling our death. Behind this curtain is a mysterious darkness that the conscious mind cannot perceive, hence no living proof of what lies beyond. When mankind finally makes the trip to Mars, the pioneering astronauts would have to carry specialized spacesuits for survival. The hard shell of a space suit protects a living being inside. Unlike manufactured spacesuits that can be replaced at a cost, this specialized spacesuit called the human body is irreplaceable.  The human body has a hard bony skeleton that supports living cells. Although life in the cells evaporates rather quickly in the matter of years, the bony skeleton can be preserved for millions of years. Going to a natural history museum and seeing skeletal remains of now extinct dinosaurs is a fascinating experience. It brings the massive scale of time into perspective. 

Sunday, August 12, 2012

Getting to the heart of a stroke - Part II

Based on a talk at the HOPE stroke support group July 2012

The word ‘stroke’ is derived from the Greek word apoplexia which means “to strike”. The first written descriptions of sudden paralysis appeared in the writings of Hippocrates, the father of modern medicine. Before the word stroke became popular, the term apoplexy was commonly used to describe this disease.

From a structural standpoint, the brain can be thought of as a house with three levels. The first floor or the lowest level is called the hindbrain. The second floor or the middle level is called the midbrain and the top floor is the forebrain. The hindbrain or the lowest part of the brain controls vital bodily functions such as breathing, heart rate and digestion. This part of the brain is connected to the spinal cord and controls many bodily functions that does not need approval from the higher centers in the brain. There is a certain amount of autonomy that is given to this part of the brain. The midbrain controls posture, movement and reflex eye movements. The midbrain is a small structure that connects the forebrain and the hindbrain. The forebrain is the largest part of the brain and most of it taken up by what is called the cerebral cortex. Of all the earthly creatures, humans have the largest cerebral cortex. The cerebral cortex fills most of the space under the skull and is divided into two halves that are interconnected. Although the two halves of the brain appear similar, they have very different functions. The right brain controls the left side of the body and the left brain controls the right side of the body. 

Getting to the heart of a stroke - Part I

Based on a talk at Dr. Purser's wellness group, July 2012.

What do economists and physicians have in common?  The world we now live in is straddled with economic woes. In the eyes of an economist, there is a sickness going around and that illness is ‘debt’. Economists make forecasts and propose fixes for the monetary structure. They look at debt from this perspective. Everyone would agree that economic growth is the best way to get out of debt. In politics, the word debt is looked at differently depending on who you talk to. One end of the spectrum, debt stands for ‘Do Everything But Tax’ and at the other end of the spectrum, ‘Do Everything By Tax’.  

The word debt has also crept into human physiology. This is an entirely different kind of debt, the kind that draws the line between health and disease, life and death. In  the human body, the stakes are a lot higher. This debt is called the oxygen debt. In simple terms, cells use oxygen. If the supply of oxygen to individual cells is interrupted, the cells don’t immediately die. They survive by other means and the cells go into debt, called the oxygen debt. If the cells don’t repay this debt by replenishing itself with fresh oxygen, cellular ‘default’ occurs. The cellular equivalent of bankruptcy called cell death then slowly sets in. Depending on the location in the body, cellular death is called different names. For, example, if cells in the heart are deprived of oxygen, a heart attack ensues and similarly if oxygen supply to the cells of brain is interrupted, brain cells die resulting in a stroke.