BF - The Nervous System Lesson

 

The Nervous System

When you woke up this morning, your heart was beating and your lungs were inhaling and exhaling air. You probably took just a moment to use your senses to become aware of the environment around you - the temperature, the lighting that indicated the time of day, the smell of breakfast in the air (hopefully!). At the same time, you were already starting to make decisions like whether you should turn off the alarm and go back to sleep or get up and face the day. All this was possible because of your nervous system.

Your brain and spinal cord together form your central nervous system, where all your decisions are made and sensations are interpreted through interneurons.

The peripheral nervous system collects information from your senses through sensory neurons and sends it to the central nervous system for processing; it also sends directions from the central nervous system out to the rest of the body through motor neurons.

The peripheral nervous system is divided into two parts: somatic and autonomic. Through the somatic nervous system, you are able to control your voluntary body movements. Your autonomic nervous system controls automatic functions like digestion and hormone production.

The autonomic nervous system has two important functions. The sympathetic nervous system arouses you when you are upset or afraid, increasing your heart rate and blood pressure, dilating your pupils, and slowing digestion to make it easy to fight or run to avoid danger. When the stressful situation is over, the parasympathetic nervous system counteracts those effects, decreasing heart rate and blood pressure, constricting pupils, and jumpstarting digestion.

 

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