Do you know that nerves work as a signal in the human body but how many nerves are in humans? If your answer is “NO” don’t worry, Follow this article to get familiar with nerves and how many nerves are in the human body.
The primary network of communication in your body is your nervous system. It regulates and maintains the numerous bodily processes along with your endocrine system. It also facilitates interaction with your environment. Therefore, a network of nerves and nerve cells make up your nervous system, which is responsible for sending and receiving signals between your brain, spinal cord, and the rest of your body.
A nerve is a group of fibers that relays information between the brain and the body. Moreover, The neurons, which are the cells that make up the nerves, change chemically and electrically to transmit the messages. In your body, how many of these nerves are there? From the top of our heads to the tips of our toes, humans are believed to have hundreds of nerves and billions of neurons, while the exact number is unknown.
If you follow this article, acknowledge yourself with what are nerves, what are the types of nerves, how many nerves are in the human being and, what are the functions of nerves.
Table of Contents
What are nerves?
Your brain sends electrical impulses to the rest of your body through your nerves, which act as cables. You may move your muscles and feel feelings thanks to these impulses. Additionally, they continue to carry out some autonomic processes like breathing, sweating, and food digestion.
Neurons are another name for nerve cells. Your body contains neurons, particularly in the brain and spinal cord. Your nervous system is built on the foundation of your nerves, brain, and spinal cord. When doctors speak to the “nerve,” they typically mean the portion of your nervous system that is not connected to your brain and spinal cord. Your peripheral nervous system is what it is known as.
Anatomically, a nerve is a sheathed, gleaming white bundle of fibers that connects the neurological system to the rest of the body. The nerves send and receive signals to and from the central nervous system. In humans, 12 pairs of cranial nerves connect to the brain, and there are typically 31 pairs of spinal nerves that connect to the spinal cord.
Individual nerves are made up of a large number of fibers, and all of them, except for those that originate in sympathetic ganglia, stretch from the brain or spinal cord to the peripheral structures that they innervate. In terms of function, nerve fibers can be categorized as either sensory (afferent) or motor (efferent). Therefore, the functional parts of the nerves are made up of the fibers in these groups and their subcategories. Individual cranial nerves have different combinations of these elements, whereas spinal nerves have more consistent combinations.
What are the types of nerves?
Your nerves fall into two categories:
- Sensory nerves: your brain receives information from your sensory nerves, which enable you to touch, taste, smell, and see.
- Motor nerves: your muscles or glands receive instructions from your motor nerves to help you move and function.
Your brain and spinal cord also have two main groupings of nerves that branch out:
The 12 pairs of cranial nerves travel from your brain through your face, head, and neck. Cranial nerves may serve sensory, motor, or both purposes. For instance, cranial nerves support your ability to move your eyes, make facial expressions, and process scents.
31 pairs of spinal nerves branch out from your spinal cord, making up your spine. These nerves can support sensory, motor, or combined functions. For instance, spinal nerves may send signals to your spinal cord from your joints and muscles. Involuntary actions like moving your hand away from a hot stove are likewise governed by spinal nerves.
How many nerves are in the human being?
The human body contains more than 7 trillion nerves, which may surprise you. The neurological system of your body is made up of all of these nerves. The nerves in your body act as electrical wiring, carrying messages from your brain, spinal cord, and other parts of your body. Find out more about these nerves’ functions and significance below.
The way the nervous system is organized
Your nervous system is divided into two groups:
- Central nervous system (CNS): this is composed of your brain and spinal cord, and serves as the body’s control center. Your skull shields your brain, while your vertebrae guard your spinal cord.
- Peripheral nervous system (PNS): Nerves that emerge from your central nervous system (CNS) make up the PNS. Axon bundles called nerves are used by the body to carry signals.
Your nervous system is divided into two groups:
It is possible to further divide the PNS into sensory and motor sections:
- Sensory nerves: Your sensory system sends data to your central nervous system (CNS) from both within and outside your body. This can include unpleasant sensations, odors, and visual images.
- Motor nerves: The CNS sends messages to the motor division, which then triggers an action. Moving your arm is an example of voluntary action, whereas the muscle contractions that help move food through your digestive tract are examples of involuntary action.
The PNS includes the cranial nerves. The 12 pairs of cranial nerves in your head. The cranial nerves can perform sensory, motor, or both types of tasks. For instance:
- The olfactory nerve does sensory work. The brain receives information about the smell from it.
- The oculomotor nerve is capable of movement. It regulates how your eyes move.
- The face nerve includes both motor and sensory capabilities. It also regulates the movement of several of the muscles in your face. It conveys taste sensations from your tongue.
Your head, face, and neck are served by cranial nerves that leave the brain. The vagus nerve, the longest cranial nerve, is an exception to this rule. It is related to the neck, heart, and digestive system, among other bodily regions.
Your PNS also includes the nerves in your spine. They diverge from the spinal cord. The 31 pairs of spinal nerves in your body. They are organized according to the region of the spine with which they are connected. Sense and movement are both carried out by spinal nerves.
This means that they can both transfer commands from the CNS to the peripheral parts of your body and send sensory data to the CNS. Dermatomes are also connected to spinal nerves. What’s more, a particular patch of skin called a dermatome is supplied by a single spinal nerve. The majority of your spinal nerves all but one transmit sensory data from this region to the CNS.
How many nerves are there overall then?
Your body contains several hundred peripheral nerves. The sensory branches of the cranial and spinal nerves are formed when the numerous sensory nerves that transmit sensation from the skin and internal organs combine. What’s more, The spinal nerves and cranial nerves’ motor segments split into smaller nerves, which then split into still smaller nerves. So, anywhere between 2 and 30 peripheral nerves can branch out of a spinal or cranial nerve.
How is a nerve cell constructed?
The neurons in your body function to carry nerve signals. They consist of three parts:
- Cell body: Similar to other cells in your body, the cell body houses a variety of cellular parts, such as the nucleus.
- Dendrites: Extending from the cell body are dendrites. Other neurons send signals to them. A neuron may have one or several dendrites.
- Axon: The axon extends from the cell body as well. It transports impulses away from the cell body where they can be picked up by other nerve cells. It is normally longer than the dendrites. Myelin, which helps to protect and insulate the axon, is frequently found covering axons.
There are 100 billion neurons in your brain alone. A reliable source (though one researcher argues that figure is closer to 86 billion trusted sources).
How do nerves function?
So how precisely do neurons function? Let’s examine a particular form of neuronal signaling below:
- An electrical impulse is sent down the length of the axon when one neuron signals another.
- The electrical signal is changed into a chemical signal at the axon’s end. As a result, substances referred to as neurotransmitters are released.
- The neurotransmitters fill the synapse, which is the space between the next neuron’s axon and dendrites.
- The chemical signal is again transformed into an electrical signal and travels the length of the neuron when the neurotransmitters link to the dendrites of the following neuron.
Axon bundles that makeup nerves cooperate to promote communication between the CNS and PNS. It’s crucial to remember that the PNS is meant when the term “peripheral nerve” is used. In the CNS, axon bundles are referred to as “tracts.”
A neurological illness might happen when nerves are harmed or aren’t signaling appropriately. Neurological illnesses come in a wide range and are caused by numerous different factors. You might be familiar with a few of them:
- Some sclerosis
- Parkinson’s condition
- Alzheimer’s condition
What are the functions of nerves?
It is possible to generalize that all neurons perform the same three basic activities by considering the roles of the three different kinds of neurons. To:
- Obtain signals (or information).
- The blending of incoming signals (to determine whether or not the information should be passed along).
- Send messages to the target cells (other neurons or muscles or glands).
The anatomy of the neuron reflects these neural functions.
Cranial nerve function
Your brain receives sensory data about the smells you experience via your olfactory nerve. Aromatic molecules, also referred to as smelly molecules, disintegrate when you breathe them in through your nose. Moreover, the olfactory epithelium is the name given to this lining. It wakes up receptors, which send nerve signals to your olfactory bulb.
The oval-shaped olfactory bulb in your nose is made up of specific nerve cell clusters. Your olfactory tract, which is situated beneath the frontal lobe of your brain, receives nerve signals from the olfactory bulb. Therefore, the parts of your brain responsible for memory and smell identification then receive nerve signals.
The sensory nerve involved in seeing is the optic nerve. Rods and cones are specialized receptors in your retina that light contacts as it enters your eye. Rods are abundant and have a great sensitivity to light. For night vision or black and white, they are more specialized. Therefore, there are fewer cones overall. Compared to rods, they are less sensitive to light and play a larger role in color vision.
Your rods and cones receive information, which is transmitted from your retina to your optic nerve. The optic chiasm is where the two optic nerves converge once inside the skull. What’s more, two distinct optic tracts are formed at the optic chiasm by nerve fibers from each half of the retina. The nerve impulses finally go through each optic tract to your visual cortex, which then interprets the data. The back of your brain contains the visual cortex.
Muscle response and pupil response are two distinct motor functions of the oculomotor nerve.
- Muscle activity: Four of the six muscles around your eyes receive motor control from your oculomotor nerve. Your eyes benefit from the movement and focus of these muscles.
- Pupil response: Student response by controlling the size of your pupil as it responds to light is also helpful.
Your midbrain, which is a section of your brainstem, is where this nerve begins. From there, it advances until it reaches the region around your eye sockets.
Your superior oblique muscle is controlled by the trochlear nerve. The eye’s downward, outward, and inward movements are controlled by this muscle. It comes out of your midbrain’s rear region. It advances, much like your oculomotor nerve, until it reaches your eye sockets, where it activates the superior oblique muscle.
The largest cranial nerve in your body, the trigeminal nerve performs both sensory and motor activities. The three divisions of the trigeminal nerve are as follows:
- Ophthalmic: Your forehead, scalp, and upper eyelids all convey sensory information to the ophthalmic division of your brain.
- Maxillary: This area transmits sensory data from your cheekbones, upper lip, and nasal cavity, which are in the center of your face.
- Mandibular: Both sensory and motor functions are performed by the mandibular division. It transmits sensory data from your chin, lower lip, and ears. It also regulates the function of the jaw and ear muscles.
The midbrain and medulla sections of your brainstem contain a collection of nuclei, or groups of nerve cells, from which the trigeminal nerve develops. What’s more? These nuclei eventually split into a sensory root and a motor root? Your trigeminal nerve’s sensory root divides into the ophthalmic, maxillary, and mandibular divisions. Hence, your trigeminal nerve’s motor root only links to the mandibular division and travels below the sensory root.
The lateral rectus muscle, which is linked to eye movement, is controlled by the abducens nerve. What’s more, this muscle controls how the eyes move outward. You might employ it to look to the side, for instance. The pons region of your brainstem is where this nerve, also known as the abducens nerve, begins. Hence, the lateral rectus muscle is eventually controlled by it as it enters your eye socket.
The facial nerve performs both motor and sensory activities, such as the following:
- Moving jaw muscles as well as your face’s expression-making muscles
- Allowing the majority of your tongue to taste
- Supplying glands, including salivary and tear-producing glands, in your head or neck
- Sending signals from your ear’s outer parts
Your facial nerve travels over a rather convoluted path. It has both a motor and a sensory root, and it starts in the pons region of your brainstem. The facial nerve is created when the two nerves eventually combine. What’s more, the facial nerve divides into smaller nerve fibers that stimulate muscles and glands or transmit sensory data both within and outside of your skull.
Hearing and balance are two sensory functions of your vestibulocochlear nerve. The vestibular and cochlear portions make up this structure:
- Part of the cochlea: Based on the sound’s loudness and pitch, specialized cells in your ear sense vibrations caused by sound. This causes nerve impulses to be produced and transmitted to the cochlear nerve.
- The vestibular part: This area also has a different collection of unique cells that can monitor the rotation and linear movements of your head. Your vestibular nerve receives this information, which is then used to correct your balance and equilibrium.
Your vestibulocochlear nerve has different origins in the cochlea and vestibular lobes of the brain. The inferior cerebellar peduncle is a region of your brain where the cochlear part begins. Your pons and medulla are where the vestibular component starts. Therefore, the vestibulocochlear nerve is made up of both parts.
Both motor and sensory functions are carried out by the glossopharyngeal nerve, including:
- Transmitting sensory data from the back of your throat, your inner ear, your sinuses, and the back of your tongue.
- Giving the back of your tongue a feeling of flavor
- Causing the stylopharyngeus, a muscle in the back of your throat, to move voluntarily
The medulla oblongata, a region of your brainstem, is where the glossopharyngeal nerve begins. It gradually penetrates your throat and neck region.
The vagus nerve has a wide range of functions. It possesses both sensory and motor abilities, such as:
- transmitting sensory data from your throat and some of your ear canals
- conveying sensory data from your heart and intestines, as well as other organs in your chest and trunk
- enabling the control of your throat’s muscles
- encouraging the movement of the muscles that transport food through your digestive tract in your chest and trunk
- supplying taste receptors close to the tongue’s root
The vagus nerve has the longest course of any cranial nerve. It stretches all the way down into your belly from your head. It starts in the medulla, a region of your brainstem.
Your neck’s muscles are under the motor control of your accessory nerve. You can move your neck and shoulders by flexing, rotating, and extending these muscles. It is split into the spinal and cranial halves. Your upper spinal cord is where the spinal component starts. Your medulla oblongata is where the cranial portion begins. Before the spinal portion of the nerve proceeds to supply the muscles in your neck, these portions momentarily come together. Hence, the vagus nerve is followed by the cranial portion.
The 12th cranial nerve is your hypoglossal nerve. The majority of the tongue’s muscles move as a result of it. Moreover, it originates in the medulla oblongata and travels via the jaw to the tongue.
Spinal nerves function
Small sensory and motor branches can be found on the spinal nerves. Each spinal neuron performs tasks that are specific to a certain area of the body. These include autonomic, sensory, and muscular movements (involuntary functions). Because their functions are so well defined, it is frequently possible to identify which spinal nerve or nerves are compromised when a specific spinal nerve suffers from an impairment.
The brain sends motor commands to the spinal nerves. The brain’s motor strip, also known as the homunculus, issues the order to govern the muscles. This order is transmitted to the spine via nerve impulses, which subsequently go to the motor root and spinal nerve. Specific motor stimulation is required. What’s more, depending on the order of the brain, it may stimulate a relatively small group of muscles by activating the entire spinal nerve or only one of its branches.
Myotomes are regions of spinal nerve control distribution across the body. They are collections of muscles supplied by nerves from a spinal nerve root. Hence, a spinal nerve branch that activates a muscle or muscles is necessary for every muscular movement. For instance, C6 controls the triceps muscle and C7 controls the biceps muscle.
The spinal nerves autonomic, or involuntary, function aids in the regulation of the body’s internal organs, including the bowels and bladder. The spinal nerves autonomic branches are less numerous than their motor and sensory counterparts.
Small nerves in the skin, muscles, joints and internal organs of the body provide messages to the spinal nerves, including touch, temperature, position, vibration, and pain. Each spinal nerve is associated with a dermatome, which is a section of the body’s skin. Therefore, Sensations from the hand are transferred to C6, C7, and C8, while those from the area around the belly button are sent to T10.
Causes of nerves pain and damage
Nerve injury comes in more than a hundred different forms. Distinct varieties may exhibit different symptoms and necessitate diverse forms of care. About 20 million Americans are thought to have peripheral nerve injuries. Hence, the frequency of this kind of harm rises with age. Up to 70% of diabetics have some degree of nerve damage.
The following is a partial list of some of the potential causes of nerve discomfort and injury.
Nerve discomfort and damage are symptoms that can be caused by a range of autoimmune disorders. These include lupus, multiple sclerosis, Guillain-Barré syndrome, inflammatory bowel disease, and uncommon conditions where the immune system targets the peripheral nerves.
Numerous factors, including cancer, can harm or cause pain to the nerves. Cancerous tumors can occasionally press against or suffocate nerves. Other times, specific cancers might lead to dietary deficits that impair nerve activity. Additionally, some people may experience nerve discomfort and nerve damage from chemotherapy and radiation treatments.
Pain in the nerves and damage to the nerves can arise from anything that causes trauma to or compression on the nerves. This includes carpal tunnel syndrome, crush injuries, and pinched neck nerves. Find out more about compressed (pinched) nerves.
Nerve damage affects up to 70% of diabetics, and as the condition worsens, the risk increases. All three types of neurons may be impacted by the catastrophic condition known as diabetic neuropathy. Most frequently, damage to sensory nerves results in burning or numbness. You should seek medical advice as soon as you can if you have diabetes and are exhibiting signs of nerve pain or damage. Find out if you’re at risk for diabetic nerve pain by taking this assessment.
Hazardous compounds and negative effects of drugs
Numerous compounds that are intentionally or unintentionally ingested into the body have the potential to harm or even kill nerves. These include prescription pharmaceuticals, such as several cancer chemotherapies and specific HIV treatments. A common cause of nerve discomfort and damage to the nerves is chronic alcohol usage. Lead, arsenic, and mercury are among the toxic compounds that could mistakenly enter your body and harm your nerves. Discover more negative effects of specific drugs.
Disorders of the motor neurons
Your brain and spinal column include motor neurons, which are nerves that connect to the muscles all over your body. Progressively deteriorating nerve damage can be a result of diseases that affect these nerves, such as Lou Gehrig’s disease or ALS (amyotrophic lateral sclerosis). Learn more about the various motor neuron illnesses.
Symptoms of nerve pain and damage, such as weakness or burning sensations, can result from dietary deficiencies, especially those in vitamins B6 and B12. Additionally, excessive alcohol consumption or the development of nutritional deficits following gastric surgery can result in nerve injury. View a list of foods that are good suppliers of vitamins and minerals.
A contagious illness
Your body’s nerves can be impacted by a few viral disorders. These illnesses include hepatitis C, HIV, the herpes virus, and Lyme disease. Check out a slideshow on the most prevalent infectious diseases in the United States.
From the spinal cord, there are 31 pairs of spinal nerves that branch out. Each performs duties associated with a certain body part. Spinal nerves can be impacted by a variety of conditions that affect the spine, viral infections, and traumatic injuries, which can cause pain, weakness, or loss of feeling. However, a full or partial recovery is frequently feasible. Treatments for spinal nerve damage depend on the underlying reason. Hence nerves are a very important part of human beings. If issues in the nerves your whole body gets disturbed.