HUMAN BODY : brain

 THE BRAIN :

    Remembering a face, solving a riddle or getting angry, feeling pain, all of this is possible thanks to the brain, the control center of the nervous system and the body. As soft as a soft egg, pink and wrinkled, the brain is sheltered by the skull. And although it represents only 2% of the body weight, it consumes 20% of its energy, which gives an idea of ​​its importance. Its main part, the brain: it is the seat of consciousness, thought, and personality. Sensory areas of the cortex : outer layer of the brain, receive data from sensors, such as the eye; its motor areas send instructions to muscles and organs; its zones of association analyze and store the messages that make possible thinking, understanding and remembering. The two other major regions of the brain are the cerebellum, which controls balance and coordinates movement, and the cerebral trunk, which regulates v functions.

    This front view of the brain highlights its three main parts:

 ● The largest; the brain, includes the two right and left hemispheres * pinkish and yellow*. 

 ● The * green * cerebellum, located at the back of the brain, also includes two areas called lobes. 

 ● The brainstem * pale pink *, on the other hand, connects the spinal brain.

Brain waves :

    Every second, millions of nerve impulses fly along neurons in the brain. These small electric currents produced by the incessant flow of messages can be recorded by a device that plots the diagram of the brain waves. These evolve according to our activity; there are then 3 types of waves :

 ■ Alpha waves that occur when you are awake but at rest. 

 ■ Beta waves, when you are active. 

 ■ Delta waves, during sleep. .

>> These diagrams called {encephalogram} allows doctors to check that the brain is in good condition.

The sleep !

    The metal plates placed on the head of this sleeping woman are electrodes.

They transmit electrical signals to a device that records the evolution of brain activity. During the first phase of sleep (deep sleep), brain activity slows down. It then increases during the light sleep phase : the eyes move very quickly, the sleeper dreams. This cycle, (deep sleep / light sleep), is repeated several times during the night.

 The brain thus has time to rest, to recharge, and to evacuate all the events of the day.

Active areas !

    Different parts of the cerebral cortex have different tasks. We can see it very well on these images with the scanner. 

 >> Hearing activates an area that receives and interprets nerve impulses from the ears.

 >> Speech involves an area located further forward that sends back implusions causing the production of sounds.

 >> Thinking and speaking activate both the areas involved in hearing, speaking, thinking, and understanding.

Hearing

Thinking and speaking

Speech 

An extraordinary network !

    There are billions of neurons like this in the brain. Each connected to tens, hundreds, even thousands of others. A nerve fiber, the axon, extends the neuron and transmits implusions to other neurons. The finer ramifications, the dendrites, receive the impulses from neighboring neurons. This gigantic network forms an ultra-fast communication system of incredible complexity.

Inside the Skull :

    This procedure of x-raying the head of a living person has "removed" the top of the skull and the left hemisphere to show the depths of the brain. We see a mass of whitish substance, the thalamus, which acts as a relay between the sensors of the body and the brain to send messages in both directions. This mass is surrounded by a kind of ring, the limbic system, responsible for emotions such as anger, fear, hope, and responsible for controlling our skills.