Nervous system
Study the following text:
Nerve systemThe nervous system is involved with everything you do. The nervous system process the stimuli recieved by your senses. The nervous system controls muscles and other things in your body.
The nervous system is divided into parts. The central nervous system is made up of the brains and the spinal cord. These are connected with the rest of the body through nerves. Another part is the peripheral nervous system, this is everything outside the central nervous system. Peripheral means 'around the edge'.
A nerve is made of nerve cells. There are three types of neurons (nerve cells):
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Impulses through the brainIn your nose and eyes there are sensory cells (sensory neurons). These sensory cells recieve the stimuli from our environment. When this happens the sensory cells create an impulse. An impulse is a small electric signal which travels through our nerves. The impulse travels through the sensory neurons to the central nervous system. Inside the brain the information is processed. You are able to think about the stimulus. The brain then sends an impulse back through the motor neurons to the muscles. These are the places the signal travels through: stimulus - sense - sensory neuron - spinal cord - brain - spinal cord - motor neurons - muscles - action
An example:
The central nervous system also manages other unconcious processes in your body, like your heartbeat and your breathing.
Impulses through the spinal cordA reflex is an automatic reaction to a stimulus. After recieving a stimulus, impulses are made in your sensory neurons. The impulses travel through the sensory neuron to the spinal cord. There the spinal cord reacts directly. Even before the impulse reaches the brian, an impulse is sent to the muscles. This impulse travels through motor neurons. These are the places the signal travels through: stimulus - sense - sensory neuron - spinal cord - motor neurons - muscles - action
Reflexes like the cough reflex, sneeze reflex, pupillary reflex and swallowing reflex are caused by the brain stem. Reflexes of the arms and legs, anus and urine bladder go through the spinal cord. An example:
BrainThe brain is a very complicated organ. All your feelings, your thoughts and your skills are inside your brain. The brain has two halves, which are both wrinkled. ![]()
The human brain has a couple of important parts which have different functions.
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Watch this video to learn more about the brain.
The cerebrum is the place where the impulses from the sensory neurons are recieved. Inside the cerebrum there are different locations for certain senses and other functions. In the picture below you can see different areas of the cerebrum with their functions. ![]()
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Now answer the following nine questions:
1. The central nervous system contains:
A. brain and sensory neurons
B. spinal cord and motor neurons
C. brain and spinal cord
2. What is the name of the nerve cells which bring an impulse from the senses to the central nervous system?
A. sensory neurons
B. interneurons
C. motor neurons
3. What is the name of the nerve cells which bring an impulse from one nerve to another?
A. sensory neurons
B. interneurons
C. motor neurons
4. What is the name of the nerve cells which bring an impulse from the central nervous system to the muscles?
A. sensory neurons
B. interneurons
C. motor neurons
5. You recieve a stimulus and react to it.
What is the right order of events?
A. sense - sensory neurons - brain - motor neurons - muscles
B. sense - motor neurons - brain - sensory neurons - muscles
C. sense - sensory neurons - motor neurons - brain - muscles
6. True or false?
When a reflex takes place, the spinal cord reacts to the stimulus.
A. True
B. False
7. True or false?
When a reflex takes place, you react before you become concious of the stimulus.
A. True
B. False
8. The part of the brain which processes impulses from the senses is called ... .
A. cerebrum
B. cerebellum
C. brain stem
9. True or false?
Motor neurons are part of the central nervous system.
A. True
B. False
When you have answered all the questions, make sure to compare your answers with a classmate. If there is an question you have answered differently, try and figure out who was right.