NERVOUS SYSTEM
Now yet computer yet devised is a complex-or awe inspiring as a contact mass of folded and wrinkled gray and white matter that is the human brain. Seat of consciousness, reason and emotion, centre of learning and skill, and storehouse of memories, brain is truly a master organs and systems of the body. Every second of our lives, the brain receives processes and acts on information. Even while we are asleep, scientists estimate, the brain receives and sends out about 50 millions messages per second. But the brain does not work alone; it relies on our sense organs for reports from the outside world; and its need a means of communicating with the rest of body. This is where the nerves come in. Through the spinal cords and the vast network of branching nerves that make up the peripheral nervous system, nerve impulses pass back and forth between the brain and every part of the body. These crucial messages not only keep us alive but enable us to feel, think, remember and carry out act as ‘simple’ as raining a hand, or as complex as writing poem.
The brain consists of three main parts. The cerebrums interpret messages from the sense organs and control such higher functions as the ability to speak reason and remember. This activity takes place largely in the outer gray layer of the cerebrum, the cortex. The cerebellum orchestrates balance and muscle coordination. The brain stem links the brain the brain with the spinal cord and helps to regulate breathing, heartbeat and other vital functions. Deep within the brain are several crucial structures: the thalamus relays sensory nerves impulses to the cerebral cortex; the hypothalamus helps to regulate appetite and sex drive; the pituitary gland activates other glands throughout the body; the basal ganglia relay outgoing impulses from the cerebral cortex and are associated with the ability to move rapidly and smoothly.
Central and peripheral nervous system- If the brain can be compared to a computer, then the nerves can be regarded as a wiring the brain depends on for input and output. The central nervous system is made up of the brain and the spinal cord, a cable of nerve tissue, about 50 centimeters long, that run from the brain down the back inside a chain of bones called vertebrae. The spinal cords serve as the main conduit for nerve impulses to and from the brain and as the relay center for the reflex actions. With the exception of 12 pairs of cranial nerves, which connect directly with the brain, all other nerves branch out from the 31 pairs of nerves rooted in the spinal cord. This vast network of nerves, called the peripheral nervous system, consists of two parts: the motor and sensory nerves of the somatic system serve those parts of the body that are under voluntary control and enable conscious and reflex actions to be carried out; the autonomic system controls such vital involuntary functions as heartbeat and breathing.
Neuromuscular coordination- A child after birth moves its limbs to its ability without any control or purpose. But as it grows, it slowly learns to the act, of crawling towards some brighter objects. That means that the child is able to see something and wants to grab it. First in that act, it may put it hands to the object but fails to get it. It is because of lack of the coordination between the brain command and muscle action. But by practice, the baby is able to reach and grab the object. You might have noticed children trying to eat of their own. Initially, the child would try to take the food to the mouth. But, the hand may take it to the ear or the eyes. It is not the purposeful action of the baby, but due to the lack of coordination between the nerves and the muscles. Slowly the baby learns to put the food in to its mouth. This acts of learning by doing, getting a proper coordination between the stimulus and response, it popularly known as neuromuscular coordination. This is not the case that ends with babies. Till our death, we lack the ability to do certain physical activities done by others easily. Since we do not have the practice on that activity, our muscles are not able to do the activity ordered by our brain. When we want to dance after seeing other doing it, we may move awkwardly due to lack of coordination. When we try to play tabla, we may not able to do like the experts. These are examples of lack of coordination between the nerves and the muscles. This quality can be developed only by practice. It is impossible to improve our general neuromuscular coordination by regularly doing physical activities and exercises. But specific neuromuscular coordination could be achieved only by constant practice of that particular act. Whether it is specific or general, constant practice only could improve it.
Reaction time- This is one of the most important qualities of physical fitness. This is the time gap between a stimulus and response. The time gap between the stimulus and the response is called the reaction time. Shorter the time taken to react to the stimulus, the better will be your coordination. This reaction plays an important role in the field of sports and games. This is also applicable in games that involve faking and moving, jumping and throwing and jumping and catching events. The reaction time is normally better with males than females as per recent research reports.
Headaches-If it is any discomfort, it is not your brain that is aching. Although problems in the brain may cause headaches, the brain itself cannot feel the pain. While it registers pain from all other parts of the body, the brain itself lacks the sensory nerves that pickup and transmit the sensation pain.
Sensory nerves, however, do exist in and around various tissues, blood vessels and membranes in the head. These are the parts that hurt when u gets a headache, usually because of tension. Like any other tissues, those in the head transmit the sensation of pain when they are under strain. In the case of headaches, the stain may occur in the two sites; in the muscles of the neck, face and scalp, and in the blood vessels of the head area. Strained muscles cause tension headaches; swollen or enlarged blood vessels cause vascular headaches.
There are many reasons why the muscles and blood vessel in your head may become headache producers. Emotional stress can cause your muscles to tighten up. So can long hours in front of a typewriter or reading a difficult text. Infections in your sinuses, teeth or ears can also trigger headaches. Drinking too much alcohol enlarges the blood vessels in your head, and this can produce a headache.
You might say that the best way to prevent common tension headaches is to avoid stressful situations and any other type of behavior that is likely to bring them on. But this is certainly easier said than done. It is sometime difficult to recognize a stressful situation, or to avoid one that you do recognize-the report you have two present to your boss, your teenager’s discipline problems, and your three hour typing assignment. But in some cases, especially where stressful confrontation is not involved, there are preventive techniques you can try.
Do not maintain the same posture, such as sitting hunched over a desk for a long time; break the monotony by talking to someone about something that has nothing to do with your immediate chore or difficulty. If you read a lot, make sure you have plenty of light to read by. Lie down or take a warm bath to relax. If such self help methods do not work, you might consider visiting a local tension clinic.
Pain – pain often serves as an important warning signal that danger is present- and once you are alerted to danger, you may react quickly and instinctively to avoid it. In other instances, your reaction may be slower but still important. Pain may be no fun, but it often acts as a warning that prevents more serious problems.
Acute pain comes on suddenly and lasts a short time. It is caused by a stimulus – the impact of a toe stubbed against a table leg or the pressure of an infection in or under a tooth. Pain sensing nerves respond to the stimulus by sending a message through a secondary nerve cable to the spinal cord and brain. This message gets through the helps of various body chemicals, many of which have only recently been discovered. To relieve this type of pain, the pain chain reaction has to be interrupted. The first step, of course, is to try and get rid of the pain stimulus – cur the tooth infection. If this cannot be done, you can take drug, called analgesics, which interface with the chemistry of pain. Chromic or long – lasting, pain differs from acute pain in that it may not be caused by a peripheral stimulus, may not respond to analgesics, and may be permanent. Such permanent pain can cause the victim and his family great emotional distress.
Stroke-A stroke is many different things – with a single underlying cause: the cutting of the blood supply to a particular part of the brain. Deprived of oxygen and nutrients supplied by the blood, brain cells quickly die, and when they do, the parts of the body controlled by those cells stops working. A stroke victim may thus lose the ability to speak or understand, he may become paralyzed or stop breathing altogether. The location of the loss of the function and its severity depend on the parts of the brain that has been injured and how badly it has been damaged.
In the majority of the cases, the blood supply to the brain is interrupted by one or two major causes: a blood clot may block an artery leading to the brain or an artery may deliver blood to certain brain cells, but the blood it releases can itself damage and kill additional brain cells.
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