Category Zoology

            Influenza is a common ailment caused by different kinds of virus and spreads very rapidly from one person to another. When a large number of people in the same area are affected it is called an epidemic of influenza. Do you know what causes influenza?

            Influenza is caused by three types of viruses, categorized as groups A, B and C. These groups also have some subgroups. Influenza of ‘A’ group virus tends to reappear in cycles of two to three years and influenza of ‘B’ in cycles of four to five years.

            Influenza may affect individuals of all ages and is generally more frequent during the colder months of the year. The infection is transmitted from one person to another through coughing and sneezing. The influenza virus settles in the lining of nose and throat. It causes sneezing, coughing and sore throat. It also causes fever, sudden chills and headache. Often the patient has pain in the body. People with influenza feel weak, their muscles and joints ache and they have a dry painful cough. In most cases, influenza lasts from three days to a week. Mortality is usually low and those who die die from other complications such as pneumonia etc.

            Some kinds of influenza are very mild but others even fatal. The epidemic ‘Spanish flu’ after World War I killed more people than the numbers of people killed in the war itself. Fortunately there has not been a recurrence of such epidemic.

            There is no specific treatment for influenza. If subsides on its own after a few days. However, drugs such as aspirin and codeine sulphate are used to relieve discomfort and control the fever. People who are usually susceptible to influenza and of weak constitution may develop serious complications in case of infection. Normally it is not a serious disease and one should not worry much about it.

          Genetics is the science of heredity, dealing with resemblances and differences between parents and their offspring. In genetics we study inheritable characteristics of plants and animals.

          The serious studies in genetics started during the last two centuries. In 1860, Gregor Mendel, an Austrian monk, made various experiments on pea plants and drew certain conclusions. He concluded through his studies that certain characteristics passed on from one generation to the next.

          The Danish Biologist Wihelm Johannsen called these factors Genes. It is now known that genes not only transmit hereditary traits but also control all the processes of life.

          In 1910, an American geneticist Thomas Hunt Morgan proved that genes are located in chromosomes and they are passed on to the offspring along with chromosomes. After this, Edward Tatum, Hargobind Khurana and others made significant contributions to the science of genetics. The scientists have discovered that nucleic acids (DNA and RNA) determine the characteristics of an organism.

          Today better varieties of food plants with stronger and more productive abilities have been developed by using genetic methods. Even better breeds of animals have been produced by this method. The study, named as ‘Genetic Engineering’ is now a modern branch of biological science.

          By using genetic engineering, the genetic structure of an organism can be changed. Subjects in modern genetic engineering include deletions, inventions, and transpositions of genes including micro-surgery. Pioneer attempts in this direction have been successful.

          By adding DNA from certain animal cells to the DNA of bacteriological cells we can even produce insulin. Genetic screening helps in determining several diseases. By taking some fluid from the uterus of a pregnant woman it can be determined whether the unborn child is a male or a female. Diseases such as haemophilia and sickle cell anemia can often be diagnosed in uterus by genetic counsellors. Early detection of genetic diseases helps doctors to treat the child for these diseases shortly after his birth.

               It is well known that vitamins are chemical substances that our body needs to stay healthy. Vitamins are found in different kinds of food. Scientists call the six kinds of vitamins as ‘A’ ‘B’ ‘C’ ‘D’ ‘E’ and ‘K’. In fact vitamin ‘B’ is a group of vitamin.

               Do you know who pioneered the discovery of vitamins? The need for vitamins was discovered accidentally by the Dutch Bacteriologist, Christiaan Eijkman (1858-1930). He first identified that chickens fed on polished rice became ill. He realized the reason that after removing the outer layer of the grains, the polished rice lacks substances now we call vitamins. His reasoning was further confirmed when Eijkman visited Indonesia in 1886 to investigate the causes of the epidemic disease ‘Beriberi’ that took a heavy toll there. He was able to show that the disease ‘Beriberi’ was caused due to a dietary deficiency. This led to the discovery of vitamins and also the recognition of vitamins as essential to health.

               Eijkman, however, did not fully realize the wider perspective of the importance of vitamins. It was Fredrick Hopkin, the British Scientist, who put forward the theory that human beings need certain amount of such substances to keep them healthy. He suggested that diseases such as rickets or scurvy could be cured by providing necessary substances in food or by other methods containing different vitamins. This was found to be true and names of vitamins were given accordingly. 

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            It is a matter of common experience that we see spots of light when hit on the head or eyes. This is referred to as seeing the stars. In fact these are flashes of light produced when our brain gets confusing signals from our eyes, after being hit on the head or eye.

            When a nerve carries a signal, it has an electric current flowing through it. And thus every signal is in the form of an electric current. But its meaning depends upon its place of origin and destination.

            When we are hit on the eye, the pressure on the eye ball upsets the nerve cells. These nerves are connected with parts of the brain that receive eye signals. Normally these signals mean light. In this case they are caused by pressure, but our brain cannot identify them. It interprets the signals as light and we see the flashes or stars.

            If you want to confuse your brain and see lights or stars, close an eyelid and press your finger gently in the corner of your eye. You would see a patch of light on the side opposite to the finger. Similarly by pressing the eyelid we can see stars. Same is the case when we are hit on the head. 

               Pain is an unpleasant feeling that is usually caused by an injury, disease or other abnormality of the body. It is a warning that something is wrong somewhere in our body. Do you know why do we feel pain?

               We feel pain if something burns or presses hard on the end of certain nerves which are known as pain receptors. These receptors are located throughout the body as well as in the skin. Each pain receptor is a part of a nerve which carries pain impulses to the brain.

               Superficial pain is caused by receptors in the skin. A person can tell the location of the superficial pain as the skin has a large number of pain receptors. It is very difficult to pin-point the location of pain in internal regions because there are only a few pain receptors there. Sometimes deep inside the body, pain may be experienced that might get transferred to some other part of the body at some distance from the actual source of the pain. Toothache is one example of such pain.

               The best treatment of pain is to treat its cause. It can be controlled by some drugs called pain killers. Aspirin is one such drug. For controlling severe pain narcotics are usually used. Long term or chronic pain is treated by interrupting the pathways of the brain or spinal cord. Opium, morphine and heroine are the important narcotics used for this purpose. These drugs cut off the paths of the nerves which carry the pain messages to the brain. The biggest disadvantage of these drugs is that they lead to addiction. In modern times, chemists have invented anaesthetic drugs and other pain killers having fewer side effects to deaden pain caused by any disease and injury.