What is blood pressure?

          The heart is a vital organ that pumps blood to different parts of the body. The outflow of the blood takes place when the heart’s left ventricle contracts. Then blood is forced into the arteries which expand to receive blood. These arteries have a muscular lining which resists this pressure. Thus blood is squeezed out of them into the smaller vessels of the body. By blood pressure we mean the amount of pressure that blood exerts on the walls of the arteries. The amount of pressure depends upon the strength of the heart muscle, the amount of blood in the circulatory system and the condition of the arteries. 





          There are two kinds of pressures – systolic and diastolic. Systolic is the maximum pressure that occurs when the left ventricle contracts. Diastolic is the minimum pressure that occurs just before the heartbeat which follows.



          When a doctor measures blood pressure, he uses an instrument in which a column of mercury rises or falls under the pressure. It is marked in millimeters. The average systolic pressure in a young man is about 120 mm of mercury and the diastolic pressure is about 80. These figures are usually stated as 120/80 or 120 over 80.



          Blood pressure usually rises with age because the arteries become less flexible. Anxiety or exercise may also cause pressure to rise temporarily. It is also increased by a number of diseases. A. person is said to have high blood pressure or hypertension if it exceeds the figure of 100 plus his age or if the diastolic pressure exceeds 100. High blood pressure can cause heart failure, apoplexy, or kidney diseases. It may also burst a blood vessel in the eye or the brain, thus causing blindness or a hemorrhage. Symptoms of high blood pressure are headaches, hot flashes and anger.



          Abnormally low blood pressure occurs when a person has a heart attack or loses large amount of blood because of some injury etc. When the blood pressure falls considerably, the oxygen supply to the brain and other parts also gets reduced. This can cause death. Physicians use drugs which contract the muscular walls of the blood vessels to raise the blood pressure.



          Abnormal high blood pressure may be due to the constriction of arteries or due to damage to one or both kidneys. Excessive weight and lack of exercise can also contribute to hypertension. Temporary high blood pressure can be due to excitement or emotional stresses.



 


Why do some people have a squint?

          A squint is a physical defect in which both eyes do not point in the same direction. This is also called strabismus or heterotropia – a disorder of the eye in which the alignment of the two ocular axes is not parallel.



          A person with this defect may have an inward squint (one eye may be directed towards the other eye), an upward or a downward squint. The squint is called ‘comitant’ if the deviation remains constant no matter in what direction the gaze is directed. It is called ‘noncomitant’ if the degree of misalignment varies with the direction of the gaze.



          Long-sightedness in children often causes an inward squint. On the other hand short-sightedness may produce an upward squint. If one or more of these muscles are paralyzed, the noncomitant squint occurs. 





          A squint is most often the result of some abnormality in the nervous controls. Acquired squints are usually due to nerve or muscle disease and cause double vision. In fact, the movement of the eye balls depends upon the action of six muscles – four of which are straight and two slanting. If the nerves of these eye muscles have developed some defect, the eye can develop a squint.



         With the progress in medical sciences now it has become possible to treat this defect. But it must be done at an early stage by wearing special glasses. These have a dark glass to cover the good eye to stop it from being used. This prevents the bad eye from becoming worse.



         Squint can also be treated by some orthoptic exercise which helps to strengthen the eye muscles. In some cases, an operation is necessary to strengthen a weak eye muscle or to weaken an extra strong one. The good eye is covered for some period before the correctional surgery. This is to enable the patient to use the previously unused eye and build up its vision.



          An interesting observation about squint-eyed people is that it is often difficult to judge the direction in which they look. 


What is the Iron-lung machine?


          The iron-lung machine was one of the earliest life-saving machines. It was invented by Philip Drinker of Harvard, U.S.A in 1929. This device is meant to aid those who have difficulty in breathing, either due to a paralysis of chest muscles or due to some disease or an accident.



         This machine has an air-tight chamber on wheels. The patient lies on a foam-rubber bed with an adjustable head and foot rests. It is operated by electricity, but has a safety device which gives a warning signal in the vent of power failure. The machine can then be operated by hand. It has a cover which can be opened to give access to the patient. The patient’s head is usually enclosed in a plastic dome.



          The machine helps in breathing by alternately reducing and increasing the air pressure around the patient’s body. When the pressure is reduced, his chest expands and air comes into his lungs through the normal air passages, as his head remains outside the machine. When the pressure is increased, the chest contracts and air is automatically expelled from the lungs.



          During a heart operation, a heart-lung machine is used. This takes over the function of the heart and lungs and the surgeon can perform the surgery safely. The technical name for this machine is the cardiopulmonary bypass machine, since it takes over the job of both heart and lungs. Blood returning along veins, from the body’s organs to the heart, is led out of the body along a tube to a gas exchange unit. Here carbon dioxide is removed from the blood and oxygen is added – thus doing the lung’s job. The blood then flows through a rotary pump which does the heart’s job and back into the main arteries. This is a very important device during heart surgery. 


What causes asthma?

          Asthma is a chronic disease of the lungs in which a person has sudden attacks of shortness of breath, wheezing and coughing. It is one of the most common diseases affecting respiration. It affects all races and both sexes equally. It usually begins in childhood or early adult life.

          Asthma is caused by a blocking of the bronchial tubes in the lungs. This blocking is caused by shrinking of the bronchial muscles, swelling of membranes lining these muscles and the presence of thick mucus called phlegm.



          Allergic bronchial asthma is the most common type of the disease. It is caused by adverse reaction to things like house dust, pollen, feathers, animal dandruff, drugs and certain foods. Strong odours or smoke may also cause its attacks. Asthma is often linked with however, another type of allergy. Different kinds of asthma may even harm other parts of the body. 





          Asthma attacks often occur after heavy physical work or in case of emotional disturbance. An infection of the nose and throat can trigger off an attack. A drastic change in the weather may also prove troublesome in this regard. Exposure to sudden changes in temperature and humidity or both may also cause an attack. Common symptoms of asthma are wheezing, a sense of suffocation, dry cough and an inability to expel air easily from the lungs.



          Asthmatic attacks usually last for half an hour to several hours. Prolonged or frequent attacks may prove dangerous if the patient is weak or suffers from malnutrition. Some 35-40 percent of childhood asthma cases improve at puberty.



           A physician identifies asthma by physical examination and allergy skin tests. From these tests, the substance to which the patient is allergic can be detected. Most doctors usually prescribe drugs such as epinephrine or ephedrine to treat it in the initial stages. Patients with very serious cases of asthma however may need to take ACTH or cortisone. Some doctors prescribe small doses or injections of asthma-causing substances. And they slowly increase the strength of these injections until the patient’s body develops a natural resistance to the allergic substances. Sometimes oxygen becomes essential for such a patient. To avoid asthma attacks one should avoid substances to which one is allergic and the situations that precipitate attacks.



 


What is physiotherapy?


          Physiotherapy is that branch of medicine which makes use of some physical agents or exercises to treat a disease or an injury. It is also called physical therapy. More strictly it is a branch of rehabilitation medicine. Doctors who specialize in this branch of medicine are called physiotherapists.



          Physiotherapy is helpful in treating many kinds of disabilities and diseases. It is often used to treat paralysis and muscle weaknesses, such as caused by poliomyelitis and multiple sclerosis. It is also used in treating heart and lung diseases. It can also be used as a treatment aid for amputations, fractures and other injuries. With the help of this treatment, the disabled person may lead a constructive and creative life.



          Many kinds of devices and treatments are used in physiotherapy. Radiant heat lamps are used for warming up the body to remove the pains in the backbone. Electric heating pads, diathermy, hydrotherapy (water treatment) and special baths are used to apply heat to the diseases or damaged parts of the body.



           Warming up of the body relieves the pain and improves the blood circulation in the body. Soon after certain injuries cooling methods are also used to reduce pain and swelling. Ultraviolet lamps are used to kill certain germs and to help healing because ultraviolet light has more energy and can destroy germs. Ultrasonic waves are used to treat inflammatory conditions of muscles and joints.



           Exercise is the most important part of physiotherapy. In fact, a layman believes that physiotherapy is concerned only with different kinds of physical exercises. However, the physiotherapists make use of various equipments such as pulleys, weights, parallel bars, stationary bicycles and dumb bells. Splints, braces, crutches and wheel chairs are also used to help disabled persons. Physiotherapists help people learn how to use these devices and develop confidence in doing daily tasks.



           Physiotherapists work in clinics, hospitals and schools for the handicapped. Nowadays the use of physiotherapy is constantly increasing.



 


Why are infants kept on milk?

          The first kind of food a baby gets is mother’s milk. Why is this so?



          Milk is a highly nutritious food substance with which the female mammals feed their young. It contains most of the nutrients needed for growth and is, for most mammals, the main source of nutrition for several months after birth. In fact the milk of each species of mammals, including human beings, is a complete, wholesome and easily digestible food for its own young ones after their birth.



          Milk is produced in special glands called mammary glands. Most of the female mammals have teats or nipples from which their young can suck milk. These teats are connected to the mammary glands by a series of tiny ducts.



          Although the same ingredients are present in the milk of all mammals, their proportions vary. Milk is 80% to 90% water. It contains proteins, carbohydrates, fats, vitamins and minerals. These constituents are needed for growth and repair of bones and tissues and of the normal functioning of the endocrine glands which produce hormones for growth. Proteins (mostly casein and albumin) supply all the essential amino acids for growth and repair. The carbohydrates (mostly lactose or milk sugar) are a good energy source and help the body absorb calcium and phosphorus. The fats are in tiny droplets. Milk is converted into soft curd in the stomach of the young due to which digestion can proceed smoothly without the disturbance that fatty foods often cause. Milk also supplies vitamins A, B, C, D, E, K and niacin. These are needed for formation of healthy bones and tissues.



          If a mother takes diet rich in necessary nutrients, her infant will invariably receive all that he requires from her milk. This will also provide certain antibodies to help build immunity to diseases. Immediately after the birth the infant needs food every three to four hours, consuming about 600 ml of milk a day. By about 6 weeks this hunger cycle will have lengthened and the infant may pass a night without needing to be fed. 



         If human babies are not fed by their mothers, they may be bottle-fed with pasteurized cow’s milk, diluted and sweetened or mixing milk powder with water. These can be a valuable substitute for breast milk, but there are hazards involved. If not properly washed, the bottle may contain many bacteria which may cause harmful diseases to the baby.



          Some mothers believe that stronger milk helps the infant to sleep and grow better. But this is a faulty reasoning. A concentrated feed will contain too much sodium and the infant’s kidneys would have to work furiously to eliminate it. This may cause dehydrations. Although the infant may appear to be growing quickly yet instead of building stronger bones and more muscles, the baby would just accumulate excess fat, which is not a healthy sign.



         Babies have also been fed on milk of goat, buffalo, reindeer, caribou, sheep, camel, llama, and mare etc.



         During the second part of the first year, the infant is gradually weaned from milk to solid food. It is important that a balanced diet is maintained for a proper healthy growth of the baby.  


What are the functions of arteries and veins in our body?

Blood must reach every cell in the body to provide it with food and oxygen, and to remove waste products. The group of organs which circulate blood through the body is called the circulatory system.



In the human beings, the circulatory system has a muscular pump called heart. It pumps the blood through long, tube-like blood vessels. Blood vessels carry the blood throughout the body to the cells. In our circulatory system there are five types of blood vessels: arteries, arterioles, capillaries, venules and veins. An artery is a large vessel that carries blood away from the heart to the cells. It branches off into the smaller arterioles which further divide into very small capillaries. The capillaries carry blood to the cells. These reunite to form larger tubes called venules. These venules merge to form large tubes called veins. Veins carry impure blood back to the heart. According to a rough estimate if all the blood vessels are joined together in a single-line they would stretch to 60,000 miles.



Blood is pumped from the right ventricle of the heart into the pulmonary artery. The pulmonary artery carries it to the lungs where it absorbs oxygen and releases carbon-dioxide. The blood returns to the left auricle of the heart through the pulmonary vein. The left auricle pumps the oxygenated blood into the left ventricle of the heart which pumps it into aorta. The aorta is the largest artery in the body. It carries blood to other arteries and arterioles. The blood absorbs food when it passes near the small intestines. The wastes from the cells are removed from the blood when it passes through the kidneys. After the blood passes through the cells of the body, delivering food and oxygen and removing wastes, it returns to the heart through the vena cava. The vena cava is the largest vein in the body. The unoxygenated blood enters the right auricle which returns it to the right ventricle. It is then pumped to the lungs to receive more oxygen.    



The muscular walls of the arteries are thick and elastic. They carry bright red, oxygen-rich blood. As the heart pumps, a wave of pressure travels along the walls of arteries and can be felt as pulse. Their walls can contract and release and can regulate the amount of blood flowing to the body tissues.



The walls of veins have three layers: elastic, muscular and lining. The veins are thinner and less muscular than the arteries. In the arms and legs the veins have valves that prevent the back flow and pooling of blood due to gravity. The veins that are swollen, stretched or coiled on themselves are called varicose veins. These can sometimes be found on the legs of older people as well as those whose jobs involve a lot of walking. Blood in the veins is under low pressure and flows slowly. Since it contains less oxygen, it turns purplish red in colour. 




What is electrocardiography?

          Electrocardiography is a system of tracing graphically, the electric impulses generated by the heart muscles during a heartbeat. The graphic record is called electrocardiogram (ECG).

          The working of the heart is regulated by electrical impulses. It’s each part including the various valves from where the blood flows in and out produces its own electric wave pattern. These electrical impulses are recorded by a machine called electrocardiograph.



          Electrocardiogram provides extremely useful information regarding the condition and performance of the heart. It is very useful in the treatment of heart ailments.



          Electrocardiograms are made by attaching electrodes to various parts of the body. These lead off the feeble heart current to the recording instrument. The four extremities and the chest become standard places for attaching the electrodes. When the electrocardiogram is switched on, an automatic pen recorder moves up and down on a chart paper and records each wave impulse. 


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Why don’t people have identical voices?

          No two persons in the world have exactly the same voice! Do you know why it differs from person to person?

          The act of speaking involves movements of hundreds of muscles in split-second co-ordination. The speech organ called larynx or voice-box is capable of producing an infinite number of sounds. It is part of the throat through which air passes. When we breathe, air passes through the larynx downwards through mouth and nose into trachea (windpipe) and finally to the lungs.



          The larynx is made up of a tough wall of cartilage. It’s inside lining has two folds of tissue stretching on each side and leaving a gap between them. These are called vocal cords. In case of simple breathing, the gap between the cords remains wide open. The cords are slack. But talking, singing or shouting involves tightening of the cords. The exhaled air causes the cords to vibrate and produce sound. Our vocal cords can be found in any of about 170 different positions.



          If the vocal cords are slack, they may vibrate about 80 times per second and the result is deep tones. If they are tensed, they vibrate rapidly, perhaps thousand times a second, and produce short sound waves or high tones or high pitch sounds.



          As a child has short vocal cords, they produce short air waves and consequently a high pitched voice. As a child grows, the vocal cords become longer and that causes the voice to become deeper. Thus the voices of adults are heavier and deeper than children’s voices.



          Similarly the voices of most adult men are deeper than those of women. This is because a man’s larynx is larger than that of a woman with longer cords.



          The pitch of a voice depends upon the length of the vocal cords. Each voice has a certain range of frequencies. It is this range that determines what kind of voice a person has. Voices can be divided into six groups: bass, baritone, and tenor for men; and alto, mezzo-soprano and soprano for women.



          The quality of human voice also depends on many other things, such as resonating spaces, lungs, nasal cavities etc. The nose, sinuses, pharynx and the oral cavity act as resonating chambers, and modify the vocal tone produced by the vocal cords. The movement of the tongue against palate, the shaping of the lips, and the arrangement of teeth also produce changes in the voice.



           Since the structures and movements of all these organs are different in different persons the voices of no two persons in the world can be the same.



 


What causes leprosy?

            You must have heard of the great service, Mother Teresa of India, the Nobel Prize winner, is rendering to lepers. Even international organizations such as the World Health Organization, UNICEF, etc are engaged in a continuous worldwide fight against leprosy. What is leprosy and how is it caused?

            Leprosy is caused by certain bacteria called Mycobacterium leprae bacillus. They attack the skin and nervous system, causing lumps and patches of discolouration on the skin. These occur mainly on the ears, face, testes and the limbs. The inner surface of the mouth and nose also get affected. When the disease spreads to the eyes, it causes blindness. The affected nerves are destroyed. The fingers and the toes may lose all sensation and become paralyzed. 



            Leprosy is mainly of two types: Lepromatous or Cutaneous; and Tuberculoid. Lepromatous is marked by wide-spread infiltration of grainy masses of inflamed tissue under the skin, face, testes and mucosal membranes of the upper respiratory tract. But the tuberculoid is marked by stain-like lesions with raised, reddish borders and patches that become insensitive to physical stimulus as they spread. The symptoms of this disease are thickening of the skin, loss of hair, deformities of bones and joints and loss of sensation in various areas of the body.



            Leprosy’s treatment involves a long-range use of Sulfone drugs to bring an immediate stop to the infection. Severe cases, however, might also need surgery. Other drugs used to treat it are sulfoxone and solapsone. An ointment named ditophal ointment is also used with some success by rubbing on the affected areas in the body. This is a volatile substance which is lethal to the leprosy bacteria. It is generally used with another therapy which is called dapsone therapy. These drugs are fairly inexpensive. According to rough estimates one in every five patients ever receives proper treatment.



            Today the reported cases of leprosy throughout the world number at least 2,000,000 and the actual number of infected-people may be as large as 10,000,000. It is still not clear how its germs spread the infection. It appears that prolonged, close physical contact with an infected person usually precedes active infection in susceptible persons. According to the experts the disease is mildly contagious. Infants born of infected parents do not develop the disease if separated from them at an early stage.



            Leprosy occurs mainly under humid, tropical and subtropical climates. The majority of lepers are found in different parts of Asia that include Japan, Korea, and the Pacific Islands.





 


What is the function of liver in our body?

          The liver is a large and vitally important organ in the abdomen. It can be thought of as a living laboratory and a chemical plant. More than hundred different processes are known to take place in it. It is reddish brown in colour and located in the upper abdominal cavity beneath the diaphragm and ribs.

          The liver is basically concerned with the digestion of food, excretion, storage and conversion of food materials, the regulation of the composition of blood and the destruction of poisonous substances. If it stops working, death is imminent within a few hours.



          In an adult person, the liver weighs about 1.5 kg. The liver is divided into two lobes – right and left. The right lobe is about three times the size of the left lobe. Pressed tightly against it is the gall-bladder. 


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What is chicken pox?

          Chicken Pox is a contagious disease that mostly affects children generally in the age group of two to six years. Adults rarely get affected by it. This disease usually occurs in epidemics.



          Chicken pox is caused by a virus, an organism too small to be seen under an ordinary microscope. It spreads easily as the virus can be carried by moisture in the air. It is transmitted by direct contact. 



          When a child gets infected with chicken pox small red spots appear on his skin. These red eruptions look like blisters and are filled with a clear fluid. There are practically no premonitory symptoms, though slight fevers for about 24 hours may precede the eruptions. Blisters keep on appearing for the first three days. However after 36 hours of the first ones having appeared, they start becoming opalescent. So by the end of three days, they can be seen in various stages of growth and decay. The blisters are more marked on the covered areas of the body, but also occur on face, limbs and on the mucus membrane of the mouth. 





          When the blisters are filled with fluid, the disease can be spread most easily because the virus particles are in the fluid. If the blister is scratched, it releases the virus and can infect other children.



          During this disease, the patient does not feel too sick. The temperature rarely goes above 39°C (102°F). However, sometimes he may feel tired and lose his appetite.



          Chicken pox does not last for very long. After four or five days, the blisters dry up and small scabs are formed. These scabs should not be scratched as they may become ulcerated.



 


What do we mean by right-eyed or left-eyed people?


We all know whether we are right-handed or left-handed. But only a few of us know whether we are right-eyed or left-eyed. This means that we do not use both our eyes equally. One eye is dominant or stronger than the other. It has been found from several studies that 65% people have an unconscious preference for the right eye, 32% for the left eye and only 3% are ambicular i.e. they use both eyes equally.



By the following experiment, you can know whether you are a right-eyed person or left-eyed.



Hold a pencil in your hand and stretch the arm in front of you at eye level. Keep both your eyes open and line the pencil up with a picture or shelf or some object on the wall. First close one eye and see the object. Then close the second eye and see the object with first. If the object remains lined up with your right eye opened, and seemed to move to the left when your left eye was opened, then your right eye is dominant and if it happens the other way, then you are left-eyed.



There are some other methods too by which the eye dominance can be determined. In this respect, one Stanley Coren conducted some experiments at the University of British Columbia. He concluded that when we see objects with the dominant eye, they appear somewhat bigger. He selected 45 people and tested them for eye dominance. It was found that 25 people were right-eyed and 20 people were left-eyed. It was interesting to note that 17 of the right-eyed subjects viewed the object bigger with their right eyes whereas 13 of the left-eyed persons felt the same difference in size with their left eyes.



According to scientists all individuals have equal refraction for both eyes; the difference in size felt by the right-eyed and left eyed persons was only psychological. It is just a matter of unconscious individual preference practiced from the beginning that leads to the dominance of one particular eye and makes people right-eyed or left-eyed. 


What is allergy?

          Hay fever, rashes on the skin, reactions to certain injections (anaphylactic shock) and some types of asthma are the more common forms of allergy in man. What is an allergy?



          An allergy is an abnormal sensitivity of the body to certain substances especially proteins. In our environment different substances causing allergic reaction are present in countless forms. They may be in pollen or dust that enter the nose or eyes, in the serum of a vaccine or an antibiotic (such as penicillin), or in some food article. Some people are also allergic to feathers and bee stings. There are literally hundreds of allergens. 



          In an allergic reaction the substance causing the reaction is called allergen or antigen, and substances formed within the body during the processes of sensitization are known as antibodies. Though antibodies are one of our main defences against infection but in the event of an allergy they produce unpleasant reactions. The abnormal antibodies on coming in contact with an allergen such as a pollen or fungus, release chemical agents such as histamine, serotonin and other slow reacting substances. The release of these substances produces symptoms of allergy characterized by a running nose, rash and breathing difficulty. Some allergic reactions take several hours to develop while there are others which occur promptly and may cause unconsciousness or even death. They produce fall in blood pressure, difficulty in breathing and a bluish tinge in the skin. 





          It is believed that an allergic substance combines with its antibody and releases a substance called ‘histamine’ in the body. It is this histamine which acts on the blood or other parts and causes allergic symptoms such as sneezing, wheezing, shortness of breath, itching, swelling and redness of the skin. On the basis of this theory antihistamine drugs have been developed for the treatment of several types of allergic reactions. The first antihistamine drug was phyrilamine maleate and today there are wide ranges of similarly acting drugs. They block the action of histamines through their chemical structure.



          Antihistamines can be used to combat hay-fever, asthma, drug rashes, reactions to stings and vaccines. So far, scientists have not succeeded in developing medicines for acute allergic reactions. Development of specific antagonists of chemical mediators of the allergic reactions is required for rational therapy of these diseases. It is important to note that allergic diseases attributable to antigens in the environment are best controlled by avoiding or eliminating the offending substance.



          Medical sciences have yet not been able to explain why certain people are allergic to certain agents, and not others. According to many doctors and scientists heredity has a role in deciding who would be allergic and to what. 


What is blood cancer or leukemia?

          Leukemia or blood cancer is a fatal disease of the blood-forming tissues wherein abnormal white blood cells are found in the blood stream. It can occur at any age and in either sex. It is even more dangerous because its cause is still unknown. Do you know what happens in this disease?



          Blood is a vital body fluid and all its constituents have a specific function. Blood has a large number of red blood cells and a comparatively smaller number of white blood cells. The red blood cells carry oxygen to all the tissues of the body. The white cells defend the body. White blood cells are produced mainly in the bone marrow and lymph glands. In the case of leukemia, something goes wrong with the tissues that produce white cells. So these cells start multiplying at an abnormal rate. A person afflicted with leukemia may have 30 to 60 times the normal number of white blood cells that a healthy person has. Simultaneously, the rate of production of red blood cells becomes extremely slow and this causes anaemia. 


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