Let's learn about our body's 'wiring system' - Peripheral Nervous System

Have you ever wondered how your brain senses that a hot cup of tea is hot when you hold it in your hand? Or how you can move your arm or walk whenever you want? Behind all this is an amazing 'wiring system' in our body. That's what we call the Peripheral Nervous System (PNS) .

What is the difference between the central and peripheral nervous systems?

Okay, let's understand this simply. Our entire nervous system is divided into two main parts.

1. Central Nervous System (CNS): This is our 'Head Office'. It consists of only our brain and spinal cord . All decisions in the body are made and everything is controlled from here.

2. Peripheral Nervous System (PNS): This is the 'telephone wire' or 'wiring' network that extends from the 'head office' throughout the body. Simply put, it includes all the nerves in our body except the brain and spinal cord. The word "peripheral" literally means "from the center out."

What is really going on with this PNS?

This system is divided into two main parts that do their jobs.

• Somatic System: This is the part of the body that controls the things we do consciously and consciously , such as waving our arms, walking, or turning a book.
• Autonomic System: This is the most amazing part. It controls things that happen to us without us even realizing it . We don't even think about them. For example, things like heart rate, breathing, digestion, and blood pressure.

Together, these two systems perform three main functions of the PNS. Let's take a look at what they are.

Types of nerve messages

Our nerves are like a rope made up of many threads. Inside this rope are different types of threads, or nerve cells. Some of them carry information to the brain, and some of them carry information from the brain.

• Sensory nerves: These carry information from different parts of the body to the brain and spinal cord , like spies.
• Motor nerves: These carry commands from the brain to places like muscles. Like an army carrying out orders.
• Autonomic nerves: These are the nerves that control the automatic functions of our organs. They receive commands from the brain and also carry information about the state of the organs back to the brain.

What is the PNS made of?

If we compare our nervous system to an upside-down tree, the brain is the root of the tree. The spinal cord is the trunk. Then the PNS is the part that spreads out from the trunk of the tree, like branches and shoots. That means it is spread throughout the body.

This system is mainly made up of two types of nerve cells.

1. Neurons: These are the main cells that send and receive messages. They have several main parts.

• Cell body: The main part of the cell.
• Axon: The long, arm-like part that extends from the cell body. This is where electrical signals are sent.
• Dendrites: Small, branch-like structures that receive chemical signals from other cells.
• Myelin:A fatty sheath. This provides a protective covering around the axon. It's like the plastic sheath on a wire that carries current . It helps signals travel quickly and safely.

2. Glial cells: These are a type of cell that helps, protects, and maintains neurons. They are like the neurons' 'helpers'.

What are the common medical conditions that affect this system?

We usually call peripheral neuropathy when the peripheral nerves are damaged. There can be many reasons for this. Some of the most common reasons we see in Sri Lanka include:

• Type 2 Diabetes: Uncontrolled diabetes is the most common cause of damage to the PNS. When blood sugar levels are high over time, it damages the small nerves. That's why diabetics experience numbness and tingling in their feet and hands.
• Autoimmune conditions: Conditions in which our own body's immune system attacks our own nerves. Examples include conditions such as lupus and Guillain-Barré syndrome.
• Infections: Some viral and bacterial infections can damage nerves. Examples include HIV, Lyme disease, and shingles.
• Medications and surgery: Some chemotherapy drugs for cancer, some antibiotics, and surgeries can cause nerve damage as a side effect.
• Poisons and toxins: Heavy metals like mercury and lead, and chemicals released from factories can be toxic to the nerves.
• Trauma: An accident can cause permanent damage to nerves by cutting, crushing, or pulling them. Sometimes, an injury can cause swelling and pinching of a nerve. Carpal tunnel syndrome is a good example of pinching of a nerve in the wrist.
• Tumors: Nerves can be compressed and damaged by cancerous or benign tumors.

What are the symptoms of a problem with the PNS?

The symptoms depend on which type of nerve is damaged.

How do I find out if there is a problem like this?

If you have these symptoms, the first thing to do is see your doctor . The doctor will examine you and, if necessary, refer you for these types of tests.

• Blood tests: To detect things like diabetes, vitamin deficiencies, and immune system problems.
• Nerve conduction tests:It measures the speed at which signals travel through nerves.
• Electromyogram (EMG): Tests the electrical activity of muscles.
• An MRI scan.
• Nerve biopsy: Sometimes a small piece of a nerve is taken and examined.

What are the treatments for these?

Treatment depends on the cause of the nerve damage. In many cases , treating the underlying cause can reduce the impact on the nerves.

• Medication: There are various types of medications to reduce pain and restore nerve function.
• Physical therapy: This is very helpful in strengthening muscles and making movements easier.
• Surgery: Surgery may be performed to release pinched nerves or reconnect severed nerves.
• Lifestyle changes: Diet and exercise are very important, especially if you have a condition like diabetes.

What should we do to maintain the health of the PNS?

In most cases, it is best to prevent these problems before they occur.

• Eat a balanced diet: Get essential nutrients for nerves, especially vitamin B12.
• Stay active and maintain a healthy body weight: This can help prevent diseases like diabetes.
• Wear safety equipment: Prevent nerve damage from accidents at work or while playing sports.
• If you have a chronic disease like diabetes, manage it well: Follow your doctor's instructions exactly. Controlling your blood sugar levels is very important to protect your nerves.

Our peripheral nervous system is an amazing network that keeps us alive and allows us to experience the world. Therefore, it is our responsibility to take care of it.