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How Many Nerves Are In The Human Body?

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How Many Nerves Are In The Human Body?

How Many Nerves Are In The Human Body? Did you ever wonder how many nerves are in the human body? Believe me or not, nearly seven trillion nerves exist in your body, mine, and others too! They are all a part of, what we call, a nervous system.

Our nervous system includes two parts – The central nervous system and the peripheral nervous system. While the former includes your brain, spinal cord, and nerves, the latter entails sensory neurons, ganglia or a cluster of neurons, and myriad other nerves connecting the different parts of your body to one another and to the central nervous system.

These nerves are what ensure the communication between your different organs and brain. Undoubtedly, each of them is crucial for normal day-to-day functioning! However, the most significant ones are as follows.

How Many Nerves Are In The Human Body?

Cranial Nerves

Cranial nerves, located at the lower surface of your brain, serve with your sensory and motor functions. There exist about 12 pairs of cranial nerves, each working for a definite task! They are what connect your brain to various body parts, such as your neck, throat, head, digestive tract, etc. They send electrical signals between these body parts for better functioning.

Olfactory Nerve

What is responsible for your sense of smell is the pair called the olfactory nerve! It sends information to the brain whenever you encounter an odor!

Yes. If and when you smell something aromatic, the molecules dissolve in your nasal cavity roof, thereby stimulating receptors to produce nerve impulses and sending them to the brain part dealing with smell recognition and memory.

Optic Nerve

No wonder optic nerves are those nerves that ensure your vision in both of your eyes, black & white images and colors, and also in darkness!

While light rays fall into your eye and meet the receptors existing in your retina, they pass along this information to your optic nerve, that in turn, channelizes the information to the visual cortex in your brain.

Oculomotor Nerve

As the name suggests, oculomotor (oculo + motor) implies eye motor or the movements related to your eyes.  It means the oculomotor nerve is the pair streamlining your eye muscle movements.

This nerve pair stimulates the movements of your upper eyelids and eyeballs, also involuntary eye functions, such as automatic lens adjustment and pupil contraction.

Trochlear Nerve

The trochlear nerve is also the cranial nerve pair working for eye movements. This nerve pair controls the superior oblique muscles in your eyes to move downward and inward. In fact, the trochlear nerve is what helps you look toward your nose and away from it.

They are also called the fourth cranial nerve. It is the smallest nerve in the human body!

Trigeminal Nerve

The largest cranial nerve in the human body, the trigeminal nerve, has both motor and sensory functions to serve!

This nerve pair help with motor-related functions like clenching your teeth or chewing. It renders sensation to your eardrum muscles as well! The trigeminal nerve connects with the sensory receptors in your face through three different parts.

Abducens Nerve

The abducens nerve pair is even involved in extraocular eye movement functioning. It particularly controls your gaze movements while moving outward. In other words, the abducens nerve regulates the lateral movements of your eyeballs!

It is the sixth cranial nerve pair and no doubt the name justifies its function right away! It performs a purely somatic motor function.

Facial Nerve

The facial nerve pair, which is the seventh cranial nerve pair, again holds both sensory and motor functions!

This nerve pair regulates the muscle movements involved in facial expression, like smiling, frowning, or raising an eyebrow.

Besides, it controls the facial gland movements. It transmits taste sensations from the tongue and your external ears.

Vestibulocochlear Nerve

The combination of two nerves in one pair, or precisely the vestibular nerve and the cochlear nerve together, is called the vestibulocochlear nerve pair.

While the vestibular nerve enables you to sense any changes in your head position so that your body can maintain a balance, the cochlear nerve allows you to hear and determine the magnitude and frequency of a sound.

Glossopharyngeal Nerve

Both sensory and motor functions lay reserved for the glossopharyngeal nerve pair in your body!

While its sensory functions involve receiving information from the tongue, tonsil, throat, and other parts in the back of your mouth, its motor function revolves around the shortening and widening of your throat via nearby muscles.

Vagus Nerve

A vagus nerve has three types of function, sensory, motor, and parasympathetic!

First, it allocates sensation to your outer ear, throat, heart, and, further, your abdominal organs. Second, it ensures that your soft palate and throat make proper movements.

And then, the vagus nerve works for your heartbeat regulation and supply of nerves to the smooth muscles in your lungs, airway, and gastrointestinal tract.

Accessory Nerve

When you flex, rotate, or stretch your shoulder and neck muscles, the accessory nerve pair comes into action! They help control the motor movements of two muscles, i.e., your neck and shoulder muscles.

It is the eleventh cranial nerve pair. It looks coiled and has cranial and spinal divisions (though debates and further studies often appear on it).

Hypoglossal Nerve

The last of the cranial nerve pair, or the twelfth one, the hypoglossal nerve, serves with necessary motor functions to your tongue muscles. Yes. This is the nerve pair that enables you to speak properly at times of your need and move substances around your mouth.

Can you make noises with your tongue, somehow like a clicking sound? This nerve pair helps you so!

Spinal Nerves

While the spinal cord begins at your brain stem and goes down to the lower back, nearly 31 nerves originate therein! Their task is to transmit messages to and from your spinal cord and different body parts.

Each spinal nerve provides sensations to a separate body part, be it skin, muscles, or any internal organ. What they do is – Functional Control and Automatic Control!

Spinal nerves are responsible for the movements in certain body parts, like your hands, arms, fingers, upper back, abdomen, etc.

Some spinal nerves are dedicated to controlling the functions of the heart, lungs, kidneys, sweat glands, and gastrointestinal system.

From our understanding, medical experts have classified the spinal nerve into five types. The classification is based on the area of the spine they are related to! They are the regional nerves, and here they go!

Cervical Nerves

Cervical nerves are those eight pairs of spinal nerves that provide control and sensation to your head, neck, arm, shoulder, hands, and face movements, whether forward, backward, or sides!

Indeed, these nerves arising from the peripheral nervous system are what help stimulate your biceps to bend the elbows and rotate the forearms. These nerves help control the muscles that allow your wrist extension.

Thoracic Nerves

Thoracic nerves are twelve of them. They originate from the back and front of the thoracic vertebrae! They serve with control and sensation to your rib cage, lungs, diaphragm, and back and abdominal muscles.

Perhaps, they are crucial for your balance, posture, and breathing. They also help expel (or cough) foreign elements from your airway.

Lumbar Nerves

Five pairs of spinal nerves are clubbed together as lumbar nerves – Those branching off from the left and right of your lumbar vertebrae.

They stimulate the sensory and motor functions of your lower limbs. They help streamline movements in your knee, feet, and toes. They enable you to sense your genital area and shake and move your hip muscles too!

Sacral Nerves

There lay five pairs of nerves originating from the lower part of the spine, the sacrum, and they are, what we refer to, as the sacral nerves.

Sacral spinal nerves help you control and sense your pelvis area and the leg. Yes. These nerves streamline the functioning of the muscles in your pelvis, i.e., the pelvic floor, bladder, and rectum.

 

Coccygeal Nerve

Last but not least, the lone traveler, the single nerve pair, the coccygeal nerve, is the one that originates from the terminating tip of your spinal cord, called conus medullaris. This nerve is what helps you control and sense your tailbone area while you sit.

The Coccygeal nerve is partially responsible for supplying nerves to some pelvic organs, like your bladder, prostate, uterus, fallopian tube, and so forth!

Bottom Line: 

Are you here? If so, you must be thinking what an unending list it is!

Well,

Think of it like the electrical wiring of your body! Don’t they seem endless too? 

I hope the blog was able to shed light on your question of how many nerves are in the human body. I hope you can now understand which are the most crucial ones from among the trillions, and I hope you have learned which nerve serves which functions.

It’s time to say goodbye today! If you have more questions in mind, the answer of which you would like to hear from us, do not hesitate to drop an email at www.healthfinder.in.

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About author
Hi, I’m Alka Tiwari, healthcare marketer at HealthFinder. I started this blog to help you provide better healthcare information directly from the doctors.
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