The nervous system is anorgan systemthat handles communication in the body.
It has all four types of neurons and is the only place where inter-neurons can be found.
There are also blood vessels inside the skull and supporting structures such as glial cells.
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The central nervous system is pretty well insulated from the outside world.
It gets nutrients from cerebrospinal fluid, a clear liquid that bathes the brain and spinal cord.
It’s possible to get an infection from viruses or bacteria in the meninges called meningitis.
The central nervous system is like the guts of your system.
Your brain makes all the calculations and stores information.
You need some sort of input and output devices.
your box uses a mouse, a touchscreen or a keyboard to sense what you want it to do.
It uses a screen and speakers to react.
Your body works very similarly.
You have sensory organs to send information to the braineyes, ears, nose, tongue, and skin.
Your input/output devices are part of your peripheral nervous system.
It has motor nerves, sensory nerves, and autonomic nerves.
Autonomic nerves act automatically, which is a way to remember them.
They are the nerves that regulate our bodies.
They are the body’s version of a thermostat, a clock, and a smoke alarm.
Autonomic nerves are loosely split into either sympathetic or parasympathetic nerves.
Think of the sympathetic nerves as the body’s accelerator, and parasympathetic nerves as the brake pedal.
Motor nerves start from the central nervous system and go out toward the far reaches of the body.
They’re called motor nerves because they always end in muscles.
Walking, talking, fighting, running, or singing all take muscles.
Sensory nerves go the other direction.
They carry signals from the outside toward the central nervous system.
They always start in a sensory organeyes, ears, nose, tongue or skin.
Inside the spinal cord are some of those inter-neurons mentioned above.
In the spinal cord, inter-neurons have a different function.
Sending Signals
Nerves carry messages via signals called impulses.
Like a computer the signal is binary; it’s either on or off.
A single nerve cell can’t send a weaker signal or a stronger signal.
It can change frequencyten impulses per second, for example, or thirtybut each impulse is exactly the same.
Impulses travel along a nerve in exactly the same way as muscle cells contract, through chemistry.
Too much or too little of any of these and neither muscles nor nerves will function properly.
The cells don’t touch each other.
Adding neurotransmitters to the bloodstream can cause nerves to send signals.
It’s also easier to understand howstrokesorconcussionsaffect the brain.
The body is a dynamic collection of chemicals constantly interacting.
The nervous system is the most basic of those interactions.
This is the foundation for understanding physiology as a whole.
StatPearls.Anatomy, central nervous system.
2021;15:703944. doi:10.3389/fncel.2021.703944
National Institute of Neurological Disorders and Stroke.Meningitis and encephalitis fact sheet.
Merck Manual (consumer version).Overview of the peripheral nervous system.
Merck Manual (consumer version).Overview of the autonomic nervous system.
Society for Neuroscience.Sending the right signals.
Stachowski NJ, Dougherty KJ.Spinal inhibitory interneurons: gatekeepers of sensorimotor pathways.Int J Mol Sci.
2021;22(5):2667. doi:10.3390/ijms22052667
StatPearls.Physiology, nerve.
Endocrine Society.What is adrenaline?
