Category Zoology

          Electroshock therapy is a method of treating certain psychiatric disorders through the use of electric current to induce shock. This therapy is generally used in treating severe endogenous depressions and some forms of schizophrenia. How it achieves its effects is still not clear?

          The electroconvulsive therapy was introduced in Rome in 1938 by U. Cerletti and L. Bini for treating psychiatric disorders. After that it has been widely used to treat manic-depressive psychosis and various other types of depression. In the electroshock therapy, two electrodes are placed in appropriate positions on the head of the patient and 50 or 60 hertz alternating current at about 70 volts is passed for about 0.1 sec. There have been modifications and variations in the basic technique. The passage of the current causes an immediate loss of consciousness and the induction of a convulsive seizure. The treatment is given three times a week for two to six weeks. In some serious cases, the doctors even resort to two or three treatments in a single day.

          This therapy can have serious side-effects and complications. Hence it should be given to a few selected patients and with great skill and proper judgement. Although, it is a valuable therapeutic method in psychiatry, in certain cases it is not effective and sometimes it may even make matters worse.  

            The term ‘Rh factor’ stands for Rhesus factor. In biology it is known as a group of antigens which exists in the red blood cells of human beings. The Rhesus system was discovered by Landsteiner in 1940 while doing research on the Rhesus monkeys regarding blood groups. The Rhesus factor in human blood involves reaction with the blood of the Rhesus monkey. In fact it refers to the presence or absence of substances or factors in the red cells. There are half a dozen Rhesus factors, but ‘D’ factor is especially important in this regard. In majority of people this factor is present and they are known as Rhesus positive (Rh+). But about 15% of the human population, however, inherits blood that lacks in Rhesus factor. Their Rh factor is thus described as Rhesus negative (Rh-).

            There is no naturally occurring anti-Rh antibody. But if by mistake Rh+ blood is transfused into a Rh- person’s system, it can stimulate production of an antibody against the foreign ‘D’ factor and this antibody may eventually destroy the donated cells. The reaction is very slow in first transfusion, but becomes fierce in second or subsequent ones.

            The Rh factor plays a significant role during pregnancy. Some or all of the children of an Rh- mother and an Rh+ father may inherit the factor from the father. When a Rh- mother conceives a Rh+ baby and the blood supplies of the mother and the baby mix during the delivery resulting in some of the baby’s blood mixing with the mother’s blood, her blood may form antibodies against the Rh factor. Although these antibodies disappear after a few months, the mother is sensitised. In subsequent pregnancies, she may produce anti-Rh bodies which would attack the baby’s red cells. As a result the child might be stillborn or may die at birth due to a heart failure or a damaged brain or jaundice. In extreme cases so many red blood cells are destroyed that the foetus may die before birth.

            It is possible to overcome the problem with an exchange transfusion, the gradual removal of the baby’s blood, a few millilitres at a time and its replacement with Rh negative blood. In this way, some 95% of the affected babies can be saved.

            The condition brought about by the Rh incompatibility is known as ‘hemolytic disease’ of the neonate. The risk has been lessened by the development of a vaccine made from the anti-Rh antibody (known as Rh immune globulin). If this is administered to the mother within 24 hours of the birth of an Rh+ baby, it removes from her blood any Rh+ cells which may have seeped in. This saves her from becoming sensitised.

            The vaccine is now given as a preventive measure to Rh- mothers and it is repeated at each pregnancy. Thus due to these precautions the number of deaths of newborn babies caused by haemolytic disease is falling rapidly.

            Cirrhosis is a liver disease which renders a part of the spongy liver tissue scarred and useless. It can be caused by excessive alcohol consumption, poor diet, poisonous fumes, hepatitis, or inflammation of the liver. Once the liver tissue gets scarred, it cannot be repaired. The liver is the largest and a very important organ in the body since it helps to digest food and keeps the blood clear. Once the liver tissue gets scarred the liver may become useless and stop making proteins and purifying the blood. 

            The commonest type of cirrhosis is known as Laennec’s cirrhosis. Although it can occur at any age, it usually affects the people between 40-60 years of age. It is more commonly found among the males than among the females. To begin with, this involves an abnormal increase in liver fat. Soon the liver starts degenerating and in the end only a little fat is left.

            Cirrhosis can block the blood vessels of the liver and cause internal bleeding. Many people afflicted by cirrhosis become weak and lose weight. In certain cases the abdomen gets swollen with excess body fluids. The patient’s skin and eyes may become yellow. 

Continue reading “What is cirrhosis of the liver?”

           The nervous system is a network of nerve cells called neurons that send information to and from all parts of the body. All animals have special cells to perform this function. The messages are in the form of electric signals or nerve impulses. They travel through the cell and are passed on to the other cells. In the animal body there are millions of nerve cells linked together to make up the nervous system. The human brain itself contains about ten thousand million nerve cells.

          The human nervous system is divided into two parts: the central nervous system and the peripheral nervous system. The central nervous system comprises the brain and the spinal cord, whereas the peripheral nervous system consists of all nerve cells and nerve fibres at the periphery. The brain is protected by the tough bones of the skull and the spinal cord is protected by the bones of the spinal column.

          There are two kinds of nerve cells or neurons: sensory neurons and motor neurons. Sensory neurons carry messages from distant parts of the body towards the brain. These relate to pain, temperature, pressure and other messages from the sense organs. The motor neurons carry messages to the muscles, telling them to contract; and to the glands, telling them to produce the secretions. The nerves of the central and peripheral nervous system are a mixture of sensory and motor neurons travelling together.

          The nervous system can also be divided on the basis of the nature of work of the neurons. If the nerves are all concerned with conscious sensations, it is called the voluntary nervous system. They carry out orders given by the brain that are directed by will. When we want to walk, write or talk we use the neurons of the voluntary system. The neurons of the autonomic system are the ones that help in carrying out the routine activities we don’t normally think about. The autonomic system regulates the heart beat, respiration, digestion, blood pressure, and other unconscious activities.

          The autonomic nervous system has two main divisions: the sympathetic and parasympathetic systems. Their activities balance each other. Nerve impulses in the sympathetic system tend to increase the rate of heart beat and the blood pressure. On the other hand the impulses in the parasympathetic system tend to have the opposite effect. Under different conditions, each system takes control of the unconscious activities.

          With the help of prescribed physical exercises, training and to some extent will power, it is possible to control some of the activities of the autonomic nervous system.

          Anaemia is a particular physical condition in which the amount of haemoglobin in the blood or the number of red blood cells in a person falls below the normal level. More specifically, it is a condition caused by the deficiency of iron in the blood. In fact, haemoglobin is a protein in the red cells that contains iron. It is carried in the red blood cells of the human blood and imparts it the red colour. Haemoglobin makes it possible for the blood to carry oxygen. The body’s tissues need oxygen to function properly. The lack of the minimum amount of red blood cells or haemoglobin would result in a poor oxygen supply to the body and hence people suffering from anaemia look pale and feel tired as they become oxygen-starved.

          In every healthy human being, haemoglobin maintains a certain level of concentration. The mean values of haemoglobin for males are 15 gm per deciliter and for females 13.5 gm per deciliter. Values which are less than 2.5 or 3 standard deviations below the mean value are indicative of anaemia. The mean values are greater for males than for the females and again greater in adults as compared to children.

          To detect anaemia, the concentration of three things in the blood is measured. These are: the haemoglobin, the red-cell count and hematocrit. If the values of these things are below the normal level, the person is said to be anaemic.

          This disease may have several causes. The major ones are: (i) defective blood formation, (ii) cell destruction, and (iii) extensive loss of blood. Moreover there are a number of physical disorders, any of which can cause different types of anaemia. Some of the specific types of anaemia are: (i) microcytic anaemia (red cells are smaller than the normal size), (ii) macrocytic anaemia (red cells are larger than the normal size), (iii) normocytic anaemia (red cells are of normal size), and (iv) hypochromic anaemia (cells contain very little haemoglobin). Anaemia resulting from sudden blood loss are generally normocytic in nature.

          Red cells have an average lifespan of 120 days in the circulation. Each day about 45,000 red cells per microlitre are removed from the blood circulation in a healthy person. They are replaced with new cells from the bone marrow. Anaemia occurs when this rate of removal of red cells from the circulation exceeds the replacement or when the production of red cells is impaired or is ineffective in delivering cells to the circulation. Anaemia also occurs due to the lack of iron in the diet. Some kinds of anaemia can be treated by eating iron-rich foods. Medicines are also available to supply iron required to maintain the desirable level.

          Anaemia which results from the increased red blood cell destruction is known as hemolytic anaemia. This may be caused by poisoning, a kind of malaria, poor diet, allergy or some hereditary condition. 

          Belly button is the little dent that we have in the belly. Though it does not serve any purpose in our daily life, yet it is a matter of interest to know what it is and why we have it.

          Before birth, a child passes through embryo and foetus stages. In these stages, its abdomen is connected to the mother’s body by a rope-like tube called the umbilical cord. Everything which an embryo or a foetus needs to survive and grow during the pre-natal phase of nine months is supplied to the unborn baby from the mother’s body through this cord. Oxygen and food from the mother’s blood are carried to it through the vein in the umbilical cord. And the wastes are excreted through the two arteries in the umbilical cord. The cord remains attached to the spot where the belly button is.

          After the child is born the role of the umbilical cord ends because the child can now eat, drink, breathe and get rid of the body’s waste by itself, using the specific organs. Hence at the time of delivery, the cord is carefully cut off as close to the belly as possible. It does not hurt the mother or the baby. A tiny piece of cord left after cutting the long umbilical cord dries within a week and falls off, leaving a scar or a dent on the abdomen. It is called the navel or belly button.