what is neuron:
Neuron is a nerve cell that possesses the ability to excite and propagate the nerve impulse to another neuron. Neurons are the most important cells of the central nervous system (brain or spinal cord), the transmission of electrical impulses from one neuron to another, is the beginning of the basis of the functioning of the brain.
Neurons to be thin bodies, are difficult to see and even in an enlarged image, until the end of the 19th century little was known about the neurons but in the year 1873, anatomist and Italian Camillo Golgi, identified different types of neurons, he discovered that silver salts dyed them black, and view its structure, this process is known as Golgi staining
Each neuron consists of a cell body that contains a cell’s nucleus and its key elements as: mitochondria, centrosome, liposome, among others. Also, it consists of an axon or Neurite, representing its main extension and which can measure several tens of centimetres which is responsible for driving the nerve impulse from the cell body to another cell, and by multiple branches known as dendrites, reception of stimuli and cell food, establish connections between neurons, connections that have function to transmit messages between neurons. Each neuron can approximately send nearly 300,000 dendrites to other neurons.
Without a coating, the axons could not transmit impulses quickly, because their electrical charge is lost. By virtue of this, many sensory and motor neurons are coated by a substance called myelin. Myelin is produced by Schwann cell, which is rolled up forming several litters around axons, Schwann cells are separated by small spaces known as knots and nerve impulses are dislocated, veering from a knot to another.
The main function of the neuron is the transmission of messages into nerve impulses from one neuron to another, this is done under a synapse, kind of small plate connection, contact, between 2 nerve cells and this occurs between the terminal button of an axon and the initial dendrites of another neuron. The transmission of messages into nerve impulses can be: electric type, characterized because her impulse travel along a nerve fiber, and chemical type, originated when the signal is transmitted from one neuron to another, in 2 cases involved chemicals or neurotransmitters: small molecules, released by a neuron that is set in another in contact with the first through a small structure, called the receiver. The best known neurotransmirores are: dopamine, acetylcholine, serotonin, norepinephrine, there are a number of other neurotransmitters such as: GABA, glutamate, endorphin, among others.
Neurons can be destroyed by various pathological processes, such as: infections, destruction linked to the action of toxic substances or progressive degeneration, as drugs. These conditions have resulted the death of the nerve cell. It’s strange that cells go through a process of regeneration but recently showed that this failure is less absolute than originally thought since certain neurons can in specific circumstances regenerate.
Sensory and motor neurons
There are 3 types of neurons: sensitive or efferent neurons are stimulated by physical factors, such as light, the intensity of the stimulus affects the speed at which neurons propagate the signal. Association neurons are stimulated by sensory neurons, analyzed information from sensory neurons and transmit orders. These commands are transmitted to the efferent or motor neurons that are responsible for in the responses of the different parts of the body.
Presynaptic and postsynaptic neuron
The transmission of messages between neurons process begins with shock quimico-electrico in the station cell membrane, representing the presynaptic neuron and when the nerve impulse reaches the end of the axon, the neuron produces a substance that settles in the synaptic space between neuron transmitter and receiver, the latter is the postsynaptic neuron.