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| No life ever grows great until it is focused, dedicated and disciplined." ~Harry E. Fosdick |
16th January 2012
Chapter on General Medical topics
This is a work in progress and will be published when 100 questions are available. This book is meant to help young doctors answer often-asked questions in the medical wards. It is meant to teach both content and style of answering. Your comments on this book are welcome. Please use the comment box below to do so. You can also write to moc.liamg|todikiwrotutdem#moc.liamg|todikiwrotutdem with your name and email address if you wish to order a copy of the book when it is published. Contributors to the book will be informed separately about their stake in this book.
23rd January 2012
The secret of the heart
The heart is an organ in the human body that continuously keeps pumping in order to supply blood to all tissues and cells. Our survival depends on the heart working in this manner. Over a life span of 70 years, it would contract approximately 7.5 million times. How does the heart do this so efficiently?
Each cardiac cycle consists of a contraction called systole and a relaxation called diastole. For a heart rate of 75 beats per minute, each cardiac cycle lasts 0.8 seconds. Of this, 0.3 seconds is systole and 0.5 seconds is diastole. During systole the heart pumps out blood while during diastole it receives blood into its chambers.
There are three things that scientists have learnt about the working of the heart. These are:
1. The heart knows what it must do – that is, it knows it must pump blood.
2. The heart works (that is, systole) for only 0.3 seconds while it relaxes (that is, diastole) for a longer period of 0.5 seconds during each cycle of 0.8 seconds.
3. The blood that the heart must pump out is given to it by the body; the heart does not need to do anything other than to relax in order to receive it.
Based on these three facts about the heart, it is possible to deduce some secrets for living effectively in this world: We must know the purpose for which we are born on earth and we must do that work, whatever it may be. Our life needs to be balanced in a 3:5 ratio between work and rest if we want to work effectively for many years. Here it is important to know that what constitutes work and what constitutes rest cannot be generalised because it depends on the individual. Finally, if we can truly relax, the intelligence that runs this universe will give us ideas for the work we are meant to do, just as the body supplies the heart with the blood that it needs to pump out.
Dr Vela Menon, MD
Faculty of Medicine, International Medical University, Malaysia
MedTutor is an online tutoring site for medical students and young doctors in Internal Medicine. Write to MedTutor at: moc.liamg|todikiwrotutdem#moc.liamg|todikiwrotutdem
