OUR NERVOUS SYSTEM: The nervous system is a net of specialized cells called neurons that coordinate the actions and transmit signals between different parts of the body. It has two parts: .-The central nervous system contains the brain and the spinal cord. .-The peripheral nervous system. consists of nerves connected to the central nervous system. 1.- THE CENTRAL NERVOUS SYSTEM: It is composed by the brain and the spinal cord. 1.1.- The brain: weighs about 1.3 Kgs There are about 40 billion nerve cells, known as neurons, in the brain. Brain controls our body, receives, analyzes and stores information. The brain has three main parts: the cerebrum, the cerebellum, and the brain stem.
.- The cerebrum: is the largest part of the human brain, it gets information from the sense organs and controls intelligence, language, thinking, memory voluntary responses‌ .- The cerebellum: is the responsible for the the coordination of voluntary motor movement, balance and equilibrium and muscle tone (for example: for walking). .- The brain stem: is the region of the brain that connects the cerebrum with the spinal cord. The brain stem also controls life supporting autonomic functions like heart movements, breathing, digestion‌
1.2.- The spinal cord: The spinal cord is the main way for information connecting the brain and peripheral nervous system. It is protected by the spinal column. It is the responsible for the involuntary responses or reflexes. They permit to react very quick without thinking. For example when we cut or burn a finger, we remove it very fast.
2.- THE PERIPHERAL NERVOUS SYSTEM: It is formed by the nerves. They are like cables that link the central nervous system with the rest of the body (organs, sense organs, muscles‌). For example if the eye receive information about something dangerous for the person, the nerves carry this information to the brain that gives the order of moving to the muscles. This order is transmitted to the muscles by the nerves too.
Spinal column
3.- NEURONS: Neurons are the cells that form the nervous system. They form brain, spinal cord, nerves‌ They carry chemical and electric impulses from one neuron to another, and this is the way they transmit information.
A typical neuron possesses: .- A cell body that has a nucleus. .- Dendrites: they are like branches that connect with other neurons. They receive chemical and electric impulses from axons from other neurons. .- Axon: It’s the longest part of the neuron. It send chemical and electric impulses to dendrites from other neurons. A neuron has lots of dendrites but never more than one axon. At the majority of synapses, signals are sent from the axon of one neuron to a dendrite of another.
NERVOUS SYSTEM:
GLOSARY-VOCABULARY:
Neurons: neuronas
brain: encéfalo
spinal cord: médula espinal
Peripherial nervous system: sistema nervioso periférico
cerebrum: cerebro
brain stem: bulbo raquídeo o tronco encefálico
Cerebellum: cerebelo
voluntary responses: respuestas voluntarias
thinking: pensamiento
movement: movimiento
balance: equilibrio
main way: vía/camino principal
spinal column: columna vertebral.
Involuntary responses,réflex: respuestas involuntarias, reflejos.
Nerves: nervios
to link: unir, conectar
cell body: cuerpo cellular
Dendrites: dendritas
axon: axón o cilindroeje
synapses: sinapsis
to send electric impulses: enviar impulses elécticos.
chemical: químico
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LINKS TO LEARN MORE (BIBLIOGRAPHY and ACKNOWLEDGMENTS): http://www.nlm.nih.gov/medlineplus/ency/imagepages/8679.htm
http://kidshealth.org/PageManager.jsp?lic=1&article_set=59295&cat_id=20607 http://faculty.washington.edu/chudler/spinal.html
http://en.wikipedia.org/wiki/Neuron