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The length of the spinal cord has a shape of the column at approximately 40-45cm.
The top of the lower part is pointed and it is like a cone.
Since the spinal cord is an important organ like brain, it is wrapped in bones and membranes to several folds. At first a spinal column protects the outside most. The spinal cord in the spinal column is protected in spinal membrane. The spinal membrane is three folds, and, from the inside, there are a buffy coat, arachnoid, and dura mater.
The spinal fluid enters between a buffy coat and the arachnoid.
Even if a spinal column receives a big shock from the outside, the spinal fluid works to moderate the shock. |
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How many nerves come out from a spinal cord? |
31 pairs of spinal cord nerves come out from the spinal cord, and they are connected with hands and feet, muscles and joints of body, and internal organs such as the stomach, the heart and a lung.
The nerve fiber of the spinal cord goes up and down, and the top leads to cerebral cortex.
The spinal cord is divided into cervical spinal cord, thoracic spinal cord, lumbar spinal cord, sacral cord. In the spinal cord, nerve cells and a nerve fiber become the bunch.
Reference URL:http://contest.thinkquest.jp/tqj1999/20151/seki11.htm |
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The whereabouts of motor nerves? |
When the right hand moves, an electrical signal comes out from the place called the motor area of the left brain and stimulates motor nerves.
These motor nerves intersect in the place called the bulbar pyramidal tract which is a cerebral part and go along the right spinal cord downwards and go to the muscle group of the right hand. |
The organization which the left foot moves is similar.
The stimulation from the right brain becomes the electrical stimulation, and it leads to the motor nerve intersected at the pyramidal tract, and go downwards the inside of left spinal cord and go to the muscle group of the foot. |
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What is sensory nerve? |
When a bee bites a right hand, an electric signal comes out from the place which feels the pain of the skin. The signal is transmitted the sensory nerve on the right side of the spinal cord, and strides over to the left side of the spinal cord for a while in a top, and goes upwards. It reaches the sensory area of the left brain, and we feel pain. |
When a bee stopped and bites a left leg, it happens that it is the same as that of a right hand.
The stimulation is transmitted the left side of the spinal cord, strides over, and we feel pain with the right brain. |
How are a sensory nerve and motor nerve running in the spinal cord? |
the back side
the stomack side |
The motor nerve indicated in light blue and blue come out to the front of the spinal cord.
Stimulation gets down from the cerebrum to each place the inside of the spinal cord.
The sensory nerve indicated in red and yellow is behind the spinal cord.
The stimulation to be painful goes to the top to the cerebrum along this nerve. |
If the accident that a nerve breaks off around a neck occurs, what will happen? |
A hand and a leg will stop moving and we will not feel a pain etc.
Let's be careful not to be injured by sports. |
