Although the nervous system is very complex, there are only two main types of cells in nerve tissue. The actual nerve cell is the neuron. It is the "conducting" cell that transmits impulses and the structural unit of the nervous system. The other type of cell is neuroglia, or glial, cell. The word "neuroglia" means "nerve glue." These cells are nonconductive and provide a support system for the neurons. They are a special type of "connective tissue" for the nervous system.
Neurons
Neurons, or nerve cells, carry out the functions of the nervous system by conducting nerve impulses. They are highly specialized and amitotic. This means that if a neuron is destroyed, it cannot be replaced because neurons do not go through mitosis. The image below illustrates the structure of a typical neuron.
Each neuron has three basic parts: cell body (soma), one or more dendrites, and a single axon.
Cell Body
In many ways, the cell body is similar to other types of cells. It has a nucleus with at least one nucleolus and contains many of the typical cytoplasmic organelles. It lacks centrioles, however. Because centrioles function in cell division, the fact that neurons lack these organelles is consistent with the amitotic nature of the cell.
Dendrites
Dendrites and axons are cytoplasmic extensions, or processes, that project from the cell body. They are sometimes referred to as fibers. Dendrites are usually, but not always, short and branching, which increases their surface area to receive signals from other neurons. The number of dendrites on a neuron varies. They are called afferent processes because they transmit impulses to the neuron cell body. There is only one axon that projects from each cell body. It is usually elongated and because it carries impulses away from the cell body, it is called an efferent process.
Axon
An axon may have infrequent branches called axon collaterals. Axons and axon collaterals terminate in many short branches or telodendria. The distal ends of the telodendria are slightly enlarged to form synaptic bulbs. Many axons are surrounded by a segmented, white, fatty substance called myelin or the myelin sheath. Myelinated fibers make up the white matter in the CNS, while cell bodies and unmyelinated fibers make the gray matter. The unmyelinated regions between the myelin segments are called the nodes of Ranvier.
In the peripheral nervous system, the myelin is produced by Schwann cells. The cytoplasm, nucleus, and outer cell membrane of the Schwann cell form a tight covering around the myelin and around the axon itself at the nodes of Ranvier. This covering is the neurilemma, which plays an important role in the regeneration of nerve fibers. In the CNS, oligodendrocytes produce myelin, but there is no neurilemma, which is why fibers within the CNS do not regenerate.
Functionally, neurons are classified as afferent, efferent, or interneurons (association neurons) according to the direction in which they transmit impulses relative to the central nervous system. Afferent, or sensory, neurons carry impulses from peripheral sense receptors to the CNS. They usually have long dendrites and relatively short axons. Efferent, or motor, neurons transmit impulses from the CNS to effector organs such as muscles and glands. Efferent neurons usually have short dendrites and long axons. Interneurons, or association neurons, are located entirely within the CNS in which they form the connecting link between the afferent and efferent neurons. They have short dendrites and may have either a short or long axon.
Neuroglia
Neuroglia cells do not conduct nerve impulses, but instead, they support, nourish, and protect the neurons. They are far more numerous than neurons and, unlike neurons, are capable of mitosis.
Tumors
Schwannomas are benign tumors of the peripheral nervous system which commonly occur in their sporadic, solitary form in otherwise normal individuals. Rarely, individuals develop multiple schwannomas arising from one or many elements of the peripheral nervous system.
Commonly called a Morton's Neuroma, this problem is a fairly common benign nerve growth and begins when the outer coating of a nerve in your foot thickens. This thickening is caused by irritation of branches of the medial and lateral plantar nerves that results when two bones repeatedly rub together.
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FAQs
Nervous tissue is found in the brain, spinal cord, and nerves. It is responsible for coordinating and controlling many body activities. It stimulates muscle contraction, creates an awareness of the environment, and plays a major role in emotions, memory, and reasoning.
How can I improve my nerve tissue? ›
A person can use exercise to improve the functioning of the nerves that serve the muscles and other peripheral parts of the body. Increasing the activity in the peripheral nervous system strengthens the nerves, in the same way that exercise strengthens the muscles.
How do you strengthen nerve cells? ›
Maintaining a nutritious diet, engaging in physical activity, and cultivating the practice of meditation are just a few of the many paths that can enhance the body's nervous system. However, if you notice any changes in your nervous system, you should schedule an appointment with your physician as soon as possible.
How do you retrain nerves? ›
Exercise can also retrain the nervous system. Regular physical activity can decrease the sensitivity of our nervous system by changing processes at a cellular level, seemingly re-calibrating danger message transmission. Importantly, exercise doesn't have to be high intensity or involve going to the gym.
What stimulates nerve growth? ›
Growth factors, such as NGF, brain-derived neurotrophic factor (BDNF), and Neurotrophin-3 (NT-3), have also been used to stimulate nerve growth. These bioactive factors were physically incorporated into scaffolds or chemically conjugated.
What rebuilds nerves? ›
Schwann cells can help damaged nerves regenerate and restore function. On average, damaged nerves can grow back at a rate of about 1 inch per month or 1 millimeter per day. Surgery is needed if there is significant scar tissue or a gap between cut nerve ends.
What are the 7 vitamins that repair nerve damage? ›
8 Great Vitamins for Neuropathy
- Acetyl-l-carnitine. Also known as ALC, Acetyl-l-carnitine is naturally produced by the liver and kidneys and can often be supplemented to treat a variety of symptoms. ...
- B-Complex Vitamins. ...
- Alpha-lipoic acid. ...
- Magnesium. ...
- Calcium. ...
- Glutamine. ...
- Glutathione. ...
- N-acetyl cysteine.
Antioxidants like CoQ10 and acetyl-l-carnitine can help to prevent or reverse nerve damage, and they help to reduce pain. Antioxidant packed foods include blueberries, fish, beans, walnuts, green veggies, and beans.
What foods repair nerve damage? ›
Lean proteins, such as poultry, fish, and legumes, are invaluable, supplying the amino acids essential for nerve repair. Whole grains, fruits, and vegetables emerge as nutrient powerhouses, brimming with vitamins and antioxidants that bolster nerve function.
How to reverse nerve damage? ›
A surgeon can remove the damaged section and directly reconnect healthy nerve ends. This is known as nerve repair. Or the surgeon may implant a piece of nerve from another part of the body to close a gap between the nerves.
B vitamins like B12, B6, B3, B1 are essential for nerve health. These vitamins can help with the healing of nerve damage and relieve nerve damage symptoms like numbness and tingling—this is why they are called 'neurotropic' vitamins.
What are the signs of nerve healing? ›
Sharp, shooting, electric pains are normal signs of nerve recovery. The signal should extend to the farthest distal nerve ending. It is the body's way of communicating the direction of where to travel. The scar should become less sensitive as a sign of recovery.
How long does it take for nerves to rebuild? ›
Regeneration time depends on how seriously your nerve was injured and the type of injury that you sustained. If your nerve is bruised or traumatized but is not cut, it should recover over 6-12 weeks. A nerve that is cut will grow at 1mm per day, after about a 4 week period of 'rest' following your injury.
Can the body rebuild nerves? ›
Some damaged nerves heal on their own, but some injuries are too severe for the nerve to regrow. If a patient has a serious peripheral nerve injury, we have methods to restore muscle function that didn't exist 30 years ago. But it's also important to know there's often a ticking clock with nerve injuries.
Can nerves regenerate? ›
Central nervous system (CNS) axons do not spontaneously regenerate after injury in adult mammals. In contrast, peripheral nervous system (PNS) axons readily regenerate, allowing recovery of function after peripheral nerve damage.
How can I repair my nerve cells naturally? ›
Green and leafy vegetables. Broccoli, spinach and asparagus all contain vitamin B, a nutrient important for nerve regeneration and nerve function. Spinach, broccoli and kale also contain a micronutrient called alpha-lipoic acid that prevents nerve damage and improves nerve function.
Can nerve tissue damage be repaired? ›
If your nerve is only injured, you may recover over time without surgery. Nerves heal slowly, sometimes over many months. For these mild nerve injuries, nonsurgical treatment options include medication, physical therapy or massage therapy. Peripheral nerve surgery can reconstruct or repair damaged nerves.
Can nerve tissue repair itself? ›
In the peripheral nervous system, nerves can regenerate on their own if injuries are small. Larger injuries must be surgically treated, typically with nerve grafts harvested from elsewhere in the body. Spinal cord injury is more complicated, as there are factors in the body that inhibit repair.
