The Nervous System

Where the  mystery all begins...

The neuron is the most basic building block of the whole nervous system. Here this image shows an example of an interneuron from the cerebral cortex. Neurons are located all throughout the nervous system and allow for the rapid communication between different organs, tissues or even cells throughout our whole body. Currently my neurons are communicating to help me type these words.

This image shows the three major parts of a neuron: the dendrites, the soma (cell body) and the axon. In the neuron, the electro-chemical message known as the action potential, is received in by the dendrites. The message then travels through the soma where it is processed by the nucleus. The message then travels down the axon where it passes on to the other neuron through the axon terminal. The myelin sheath is composed of Schawnn cells and this sheath helps prevent the loss of the electrochemical message traveling down the axon. Here is a video than can help you visualize this amazing phenomon...

After a message travels through a neuron, the neuron then communicates with other neurons through a synapse. This synapse is where the neurotransmitters travel across a synaptic gap from the axon terminal of one neuron to the membrane receptors of a receiving neuron's dendrites. The synapse was discovered by Sir Charles Sherrington who noticed neural impulses took a long time to travel a neural pathway. Here is a video of the communication between neurons.

The Brain

Also known as the most interesting organ ever known to man kind, the brain, is the basis to our existence and success as a species. The cerebrum is the main part of the brain and is composed of four lobes along with a motor cortex and sensory cortex. The four lobes of the brain are frontal, parietal, temporal and occipital. Each lobe and cortex has a different function.

Another major part of the brain is the cerebellum. This sponge looking part of the back of the brain plays a huge rule in helping control your balance and kinesthesis.  Here is an image of the cerebellum

Another major part of the brain is the limbic system. This system is located in the center of the brain and is responsible for emotions and homeostasis. Here is a diagram of the limbic system and nearby structures.

The Amygdala's function was confirmed by Heinrich Kl├╝ver and Paul Bucy who surgically lesioned the brain of a rhesus monkey. The result? The normally ill-tempered monkey turned into the most mellow of creatures. Poke it, pinch it, do virtually anything that normally would trigger a ferocious response, and still the animal remained placid.

The Peripheral Nervous System

Autonomic nervous system controls our glands and the muscles of our internal organs, influencing such functions as glandular activity, heartbeat, and digestion.

It is broken up into the sympathetic and parasympathetic divisions. The sympathetic arouses the body and the parasympathetic calms the body. Specific examples are shown in the diagram below.

The Autonomic and Somatic

The Somatic nervous system enables voluntary control of our skeletal muscles. For example, as the bell signals the end of class, your somatic nervous system reports to your brain the current state of your skeletal muscles and carries instructions back, triggering your body to rise from your seat.

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