Fun Facts About The Nervous System: The human body is made up of a system that enables us to access our five senses, and interpret information according to what we see, smell, taste, hear or touch. Imagine not being able to interpret information that is gathered by our eyes or our sense of touch. We are incomplete without our senses, and thus incomplete without the vital system that governs them, known as the nervous system.
The nervous system is a complicated web of nerve fibers and cells that run to and from the brain and spinal cord throughout the body. It innervates every organ in the body and is responsible for carrying messages to the brain to be interpreted.
There are two parts to the nervous system – the central nervous system and the peripheral nervous system. The peripheral nervous system is further comprised of two subdivisions – the somatic and the autonomic nervous system.
The basic functional unit of the nervous system is the neuron. There are billions of neurons in the nervous system, most of them in the brain. The neuron consists of long cables like extensions that protrude out of its body termed as axons and short, thick extensions termed as dendrites.
Together, axons and dendrites act as cables to carry messages to and from the brain and spinal cord.
Billions of these neurons work in conjunction with the brain to provide information about the surroundings to the human body.
Top 25 Fun Facts About The Nervous System
The nervous system is a wonder in itself, a complicated system without which other systems would not function fully. Here are 25 fun facts about the nervous system:
1. The brain requires and utilizes more energy than any other organ in the body
The brain uses more than 20% of the body’s total energy production. Most of this energy is channeled through the brain towards the transmission of electrical impulses whether we are awake or asleep. It is a well-known fact that the brain works tirelessly even during sleep.
2. The brain’s structure is not static; it changes with acquiring new knowledge
The structure and density of the brain of an infant vary significantly with an adolescent or an adult. This is due to the learning process which contributes towards the development of new neuronal connections in the brain. The more we learn, the more electrical connections are generated in our brains. These connections help in establishing memory, and the more they are reinforced, the stronger the memory. As they say – practice makes perfect!
3. The transmission rate of the axon in a neuronal cell is about 2500 per second
The axon, which is the elongated cable-like protrusion from the neuronal cell responsible for transmitting signals, can transmit a large 2500 signals per second. The path of the signal transmitted is directed by chemical messengers which allow it to switch to different parts of the neuronal circuit.
4. The average length of the spinal cord measures to about 19 inches, but holds 10 million neurons
The spinal cord works together with a brain as well as independently. Some reflexes are handled by the spinal cord alone, and it contains 10 million neurons. The bunch of nerves that arise from the spinal cord are known as spinal nerves.
5. In reality, brain control is opposite of what is typically thought
The left part of the brain controls the right side of the body, and the right part of the brain controls the left side of the body. It was also previously believed that dominantly left-brained people, which means the left brain is more active and dominant than the right, tend to be more creative and artistic, whereas dominantly right-brained, which means the right brain is more dominant and active than the left, tend to be more rational and logical. However, scientific research has proved that it is not all that simple.
6. The messages in the nervous system are conducted and transmitted at an incredible rate
Electrical impulses in the nervous system travel at a speed of 180mph. This speed enables us to interpret information in the blink of an eye.
7. Reflexes that are involuntary are not interpreted and processed by the brain
Certain reflexes are involuntary, which means they are automatic and do not require the intervention of a thinking process. For example, when you touch something hot and pull your hand back away immediately. This reflex is controlled by reflex arcs, and the brain is not involved in this pathway.
8. Electrical impulses are chemicals
Current electricity is transmitted from one point to another due to the flow of electrons. Similarly, electrical impulses that flow through neurons and nerve cells are conducted by the flow of tiny chemical.
9. Potassium and sodium ions are indispensable to the functioning of the nervous system
Potassium and sodium ions are very vital for transmission of electrical impulses in the nervous systems.
10. Only a small part of the brain is active
There are over 100 billion cells in the brain. However, only 4% of these cells are active and involved in electrical impulse generation and transmission. The rest of the cells are in a dormant or resting phase.
11. There are more cells in the human brain than human beings on the planet
The number of nerve cells or neurons in the human brain is over 100 billion. However, the current world population stands at 7.8 billion individuals.
12. As we grow, our brain shrinks
Inside the womb, neurons grow at the rate of 250,000 neurons a minute in the brain of a child. The brain of a newborn grows over three times its size in the first year of growth. In adults, every year a gram of the brain’s weight is lost.
13. The nervous system cannot efficiently repair itself
The nervous system has limited regenerative or repair potential. Scientists are now looking at stem cells in the nervous system to uncover their potential in neuronal repair and regrowth.
14. The hypothalamus helps in regulating body temperature
The hypothalamus is a small part of the brain that regulates body temperature. When the body gets too cold, signals are sent to the brain which helps warm the body and maintains body temperature. Refer to homeostasis for more details.
15. The weight of the brain varies between the sexes
The adult male brain weighs about 1375g whereas the adult female brain weighs about 1275g.
16. The composition of the brain varies between the sexes
Male brains have more gray matter content, whereas female brains have white matter content. The gray matter consists of whole neuronal cells while white matter contains neuronal connections.
17. A cross-connection exists in the case of vision
The optic nerve carries information from the eyes to the brain for it to be interpreted. However, the right optic nerve crosses over the left and transmits a signal to the left side of the brain, while the left optic nerve transmits signals to the right side of the brain. Together these signals enable to brain to interpret the image formed at the retina.
18. There are other cells that aid the neurons in signal transmission and maintenance
Glial cells are support cells that help create myelin – a substance that coats the neurons and the nerve fibers. Myelin helps insulate the fibers, preventing leakage of electrical impulses and provides protection to the nerve fibers. It helps in efficient and fast transmission of signals.
19. The existence of mirror neurons
Scientists have found a group of neuronal cells in primates that help enable them to mimic the action of other animals. These neurons are called mirror neurons and are not found in human beings.
20. Neurons have different functions
Neurons are of different types, morphologies and perform different functions. Neurons that gather information from the immediate surroundings and stimuli are known as receptor neurons. Those that carry signals to the nervous system are called sensory neurons, and those that bring signals or information back to the effector organ are termed motor neurons.
21. The autonomous nervous system has two important functions
The autonomous nervous system has an interesting feature. It is activated under emergencies and stress conditions and transmits signals to either “fight” or “flight” (run away). It is also activated in normal conditions such as rest and digestion.
22. The Sciatic nerve is the longest nerve in the body
The sciatic nerve runs from the spine to the toe and is a continuous length of fibers. In certain individuals and pregnancy, this nerve can be pinched, either due to the weight of the baby carried in the womb, or due to a spinal disc problem that pinches the nerve; and can cause pain originating from the lower back to the toe. The condition is called sciatica.
23. Neuronal cells do not divide
Neuronal cells do not undergo the process of mitosis or cell division; hence they do not have growth or repair capacity. Nerve damage is usually irreversible and can result in loss of function. Today, researchers are exploring the potential of neuronal stem cells or pluripotent stem cells in neuronal repair and regeneration.
24. There are 43 pairs of nerves in the peripheral nervous system
In total there are 43 pairs of nerves in the peripheral nervous system. Out of the 43 pairs of nerves, 12 pairs are connected directly with the brain, and 31 pairs are connected to the spinal cord.
25. Nerve endings act as receptors
Receptor neurons are located in the nerve endings, which acquire a signal from the environment. For example, the nerve endings in the tips of the fingers can signal an individual to pull back their hand upon touching a hot object. In a matter of milliseconds, information is processed to perform the required action.
Without the proper functioning of the nervous system, all other systems would not be able to function optimally. The nervous system is indispensable to the human body and gives us the ability to interact with the world.