Anti aging guide

The Other Parts of the Nervous System



What is the central nervous system (CNS) and how the brain sends message and receives various sensory signals?

The brain sends messages down the spinal cord to the various segments of the body and receives messages coming up the cord from them: the brain and the spinal cord are known as the central nervous system (CNS). The nerves which branch out from the cord to instruct the muscles to contract, or to receive various sensory signals from the skin and also from deeper organs are called the peripheral nerves. The speed of conduction of an impulse along a nerve is usually thought to be about 15 per cent lower in a person of 80 than in someone of 30. The physical reaction involved in jamming on the brakes in a car requires you to see the oncoming vehicle, transmit that message a few centimeters to the brain, make a judgement about the right thing to do, and send an impulse down the spinal cord which is then relayed down the sciatic nerve to the big muscle at the back of the calf telling it to contract and thereby depress the brake. pedal. It is very difficult to make all the measurements necessary to tease apart the various components of this rather complex process, but it is probable that what takes the most time is the central function of evaluating the information in the brain and forming a decision to act on the basis of that information. The speed of this central component appears to decline more with age than that of the transmission of the signal down the sciatic nerve. The received wisdom is that the overall reaction time is 30-40 per cent longer in old age. The example chosen was a fairly simple one, and the reactions required in sporting activities such as tennis involve more complex responses, for example turning, running, and operating the racket arm. In elderly subjects who take regular exercise the total reaction time has been found to be similar to that in younger individuals and faster than in sedentary people of the same age.

Posted by Carol Hudgens - April 29, 2012 at 8:26 am