The Nervous System Christian Cosmer Meghan Mahoney Connor Myers Maïca Pichler Emily Weinstein

The Basics The nervous system is a network of cells that send electrical and chemical signals all over the body in order to coordinate our actions. These cells are called neurons (or nerves). Neurons contain vesicles that hold neurotransmitters, molecules that transmit signals to be sent from one neuron to another. The electrical signal within the vesicles need to become chemical signals when bridging the gap between the neurons. This gap is called the chemical synapse.

Electrical to Chemical In order for an electrical signal to become a chemical signal, a stimulus is required to excite the vesicles that contain neurotransmitters. The electrical stimulus gives energy for the vesicles to perform exocytosis. The vesicles perform exocytosis with the neural membrane and release the neurotransmitter, in chemical form, into the chemical synapse.

Bridging the Gap Electrical signals need to become chemical signals in order to cross the chemical synapse because neurons never touch, and an electrical signal can only be transferred through contact. The post-synaptic neuron receives the chemical signals and binds them to their receptor proteins on the dendrite. These chemical signals are then turned back into electrical signals in the post- synaptic cell by activating the sodium and potassium pumps. The gap between two neurons is similar to the gap between a plug and an outlet. The electrical current from the plug can only be transferred to the outlet when they come in contact. Only chemical signals can be sent from the plug to the outlet.

Serotonin Location: Brain Neurotransmitter linked to mood/emotion, anxiety, sleep, behavior, and appetite. Held in vesicles inside brain neurons, then released when stimulated. When there is too much stimulation, migraines occur because of the rapid fluctuation of serotonin levels. During a migraine, low amounts of serotonin are present, causing blood vessels to be larger. This increase in size irritates nerve endings and reduces blood flow. The imbalance of these neurotransmitters in the brain can also cause depression. Zoloft Commercial

Adrenaline (Epinephrine) Location: Adrenal Medulla Example of a neurotransmitter functioning within the body. Increases heart rate, blood pressure, respiratory rate. Muscles and bones communicate through tendons, which carry electrical impulses from the nervous system. Blood flows more easily to muscles, increasing oxygen intake and the muscles function at elevated levels. This can also cause anxiety. Also facilitates conversion of glycogen into glucose, giving muscles a quick burst of energy.

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