Our body is made up of several biological systems like the digestive system, respiratory system, excretory system, integumentary system, etc. Each system of our body has its own set of functions and roles to play.
The nervous system communicates with other systems of our body. Today let us learn about nervous system facts.
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Before jumping into facts, we will talk about the nervous system, the parts of the nervous system in brief.
What is the Nervous System?
The nervous system is a system of our body that receives sensory information from different organs and commands them how to act.
For example: If you touch something hot (consider a hot coffee mug), you immediately withdraw your hand. Why? What happened?
When you touched a hot mug, the sensory neurons in the skin send a signal to your central nervous system (CNS) about touching something hot. The CNS processes the information, finds out a solution, relays the solution (in this case, removing your hand) back to the skin via motor neurons.
It is only then that you will remove your hand. It looks complex, and it is complex. It looks long, but it takes mere milliseconds for the whole thing to take place.
It even understands the changes in the surroundings. It directs other organs to respond to the surroundings in a particular way to maintain equilibrium.
For example: During extreme hot weather(surroundings), your brain sends signals to your skin to start sweating. As the sweat evaporates, your body starts to cool down (reaction to counter the effect of surroundings).
The same is the case when you are feeling cold; your body starts shivering whereby energy is released, and you start to feel warm.
Parts of the Nervous System
There are two significant parts of the nervous system – the central nervous system and the peripheral nervous system.
The central nervous system is the command center of our body. It consists of the brain and spinal cord.
The peripheral nervous system (PNS) is the communicative or relay system between the central nervous system and our body. It is again divided into two parts – the somatic nervous system and the autonomic nervous system. It consists of cranial and spinal nerves.
The somatic nervous system consists of the neurons that perform voluntary movements of our body. These neurons stimulate skeletal muscles in our body.
The autonomic nervous system consists of the neurons that perform involuntary movements of our body. These neurons stimulate involuntary muscles.
Again, the autonomic nervous system is divided into two parts. They are the sympathetic and parasympathetic nervous systems.
The sympathetic nervous system (SNS) forms to fight, flight, or freight response of our body in response to danger, stress, exercise, embarrassment, excitement, etc.
The parasympathetic nervous system (PNS) is exactly the opposite of the sympathetic nervous system.
It activates our ‘rest and digests,’ ‘feed, and breed’ activities.
It undoes the effects of the sympathetic nervous system. It increases digestion and restores standard heart rate and respiration rate.
The enteric nervous system consists of the fibers of both SNS and PNS. It controls the activities of the digestive system, including peristalsis.
Now that we understood more or less about our nervous system let us start our facts.
Nervous System Facts 1-5
1. The brain alone has 100+ billion neurons. There are another 13.5 million neurons in the spinal cord.
2. Just like cells in general, neurons come in different shapes and sizes. The shape and size mostly depend on the location of the neurons in the body.
3. There are four types of neurons. The four types of neurons are briefly described below.
- Sensory neurons – These neurons collect information from different parts of the body and send them to the brain or spinal cord.
- Motor neurons – These neurons send information from the central nervous system to the different parts of the body.
- Interneurons – These are the neurons that send information from one neuron to the other neuron.
- Receptors – They sense external stimuli (sunlight, chemicals, etc.) and convert them into electrochemical energy and ultimately sends to the sensory neurons.
4. The body can send messages to our brain at a speed of 200 mph or miles per hour.
5. The nervous system starts shrinking as we age. The system shrinks 1 to 2 grams each year. The leading cause of shrinking is the loss of neurons.
Nervous System Facts 6-10
6. The slowest signal transmission takes place in the skin. Skin sends signals to the brain at a speed of 1 mile per hour.
7. Damage to the nervous system is one of the reasons of malfunctioning of other systems of our body.
8. The longest nerve of our body is the sciatic nerve. It starts from the lower back and ends at the toe. It is also the widest nerve of our body.
10. Most of the damages to the nervous system is irreversible because the neurons can’t divide or repair themselves.
Nervous System Facts 11-15
11. The optic nerve, a cranial nerve, is the single most important nerve of the eye. The structure of the eye contains million to billion optic nerve fibers and sends sensory information to the brain.
12. Alpha motor neurons come first in the race of the fastest signal transmission. They send signals to the brain at a rate of 260 to 280 miles per hour.
15. If we line up all the neurons of our body, it would be over 965 kilometers long!
Nervous System Facts 16-20
16. The brain of a newborn baby triples its size in the first year.
17. The right side of the brain controls the left side of the body, and the brain’s left side controls the right side of the body.
18. Apart from neurons, glial cells are present in the brain. They support neurons. They produce myelin, which helps in transmitting the signals faster with less loss of energy.
19. Glial cells also kill microbes and supply nutrients to the neurons.
20. Primates have neurons that are called mirror neurons. These neurons are responsible for behaviors being contagious, like yawning.
Nervous System Facts 21-25
21. We start losing neurons from the age of 20. One-tenth of our neurons are lost by the age of 75!
22. Some actions are called reflexes. The sensory neurons send the information to the spinal cord and not to the brain; the spinal cord quickly sends the signal via spinal motor neurons. This neural pathway is called the reflex arc.
23. The brain keeps on working even after you sleep.
24. The brain uses over 20% of the energy reserves of our body.
25. As we keep on learning new things, the structure of our brain changes. New neural connections form, and this causes an increase in the density of the brain.
Nervous System Facts 26-30
26. As crazy as it may sound but scientists are trying their level best to hack brains! They are developing ways to hack our immunity so that they can control brains.
27. If successful, the cells would be programmed to react to light. This would help in understanding more about the brain. It may even help in treating autoimmune disorders.
28. There are several disorders and diseases related to the nervous system. One of the common symptoms of nervous system damage is pain.
29. Epilepsy, Alzheimer’s disease, Multiple Sclerosis, Huntington’s disease, Parkinson’s disease, and Amyotrophic Lateral Sclerosis are some of the brain diseases and disorders.
30. The branch of medicine that deals with the nervous system is neurology. Doctors and surgeons who practice in this field of medicine are called neurologists and neurosurgeons.