Nervous System

What is the Nervous System?

The nervous system is a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body.

Here is the Nervous System Diagram:

The nervous system is made up of two main parts:

• The Central Nervous System (CNS) – This includes the brain and spinal cord, which process information and make decisions.

• The Peripheral Nervous System (PNS) – This consists of nerves that spread throughout the body, carrying messages between the brain, spinal cord, and muscles.

Every time you catch a ball, feel pain, laugh at a joke, or remember a friend’s birthday, your nervous system is at work.

The nervous system functions by sending and receiving signals at lightning speed, making sure our body responds instantly to whatever is happening around us.

Without the nervous system, we would not be able to experience the world in the way we do. It is the nervous system that helps us think, move, feel, and react.

Also Read: Digestive System

Anatomy of the Nervous System - What are the Parts of the Nervous System?

The two main components of the nervous system are:

Central Nervous System (CNS) – The Command Centre

This is the centre of the nervous system, where all the important decisions are made. It includes:

• Brain, the mastermind of our body plays a central role in controlling and coordinating all bodily functions
• Spinal Cord is connected to the brain at the brain stem and is covered by the vertebrae of the spine.

Peripheral Nervous System (PNS) – The Messenger System

• The peripheral nervous system (PNS) is the part of the nervous system outside of the Central Nervous System (CNS)
• It is mainly composed of nerves and ganglia, which function by sending signals to and receiving signals from the Central Nervous System (CNS)
• The peripheral nervous system (PNS) is divided into the somatic nervous system and the autonomic nervous system.

Somatic Nervous System:

The somatic nervous system controls all the body’s voluntary movements, such as walking, running, writing, or waving

Autonomic Nervous System:

The autonomic nervous system controls all the body's involuntary functions, such as breathing, the heartbeat and digestion.

The autonomic nervous system is further divided into:

The Sympathetic Nervous System:

• The sympathetic nervous system prepares our body for situations that require strength and situations that arouse fear, anger, excitement or embarrassment. This is called the fight-or-flight response
• During such situations, this nervous system causes the heart to beat faster, makes us breathe quicker and more shallowly, dilates the pupils and increases metabolism

The Parasympathetic Nervous System:

• The parasympathetic nervous system has a calming effect on the body
• It maintains the normal heart rate and breathing, constricts the pupil,s and slows down metabolism to conserve energy

Overall, the nervous system parts function in perfect sync, making sure we move, react, and stay alive without even thinking about it. 

Physiology of the Nervous System 

The main function of the nervous system is to coordinate body activities by transmitting signals, enabling perception, thought, movement and vital functions. Our nervous system uses nerve cells called neurons to send signals, or messages, all over the body. 

Here are the primary functions of the nervous system.

• Receiving and perceiving special sensations (taste, smell, vision, and sounds)
• Response generation (making our muscles move or causing us to feel pain)
• Integration of sensory information from different parts of the body and processing it
• Reception of general sensory information (touch, pressure, temperature, pain, vibration)

The nervous system is responsible for:

• Thinking & Decision-Making 
• Feeling Emotions & Memories 
• Sending & Receiving Messages
• Reflex Actions & Quick Responses

Here is what the nervous system does:

• Brain - It controls most body functions, including awareness, emotions, body movements, sensations, thoughts, speech and memory

• Spinal Cord - It functions by carrying signals back and forth between the brain and the nerves in the rest of the body

• Controls Movement – It tells our muscles when to move, whether we are walking, jumping, or even just waving at someone

• Processes Information – It helps us to understand the world by interpreting what we see, hear, touch, smell, and taste

• Sends Quick Responses – It helps us to withdraw our hands if we accidentally touch something hot before we even realise it!
• Handles Emotions & Memory – It helps us to feel happy, sad, excited, or nervous and even stores all our memories so that we can recall them later

The messages sent by the nervous system from various parts of our body to our brain, and from our brain back out to our body parts to tell our body what to do. These messages regulate our:

• Sleep
• Digestion
• Healing of wounds
• Metabolic functions
• Response to stressful situations
• Heartbeat and breathing patterns
• Movements (balance and coordination)
• Thoughts, memory, learning and feelings
• Senses (how our brain interprets what we see, hear, taste, touch and feel) and more

The nervous system functions non-stop to keep us alive, aware, and in action. 

The Human Brain:

Our brain is like the control centre of the nervous system that makes decisions and sends instructions. It also helps us to think, feel, and remember things.

The Spinal Cord:

The spinal cord functions by carrying messages between the brain and the rest of the body. 

Nerves -The Messengers: 

Nerves are the fundamental units of the nervous system, which are spread throughout our body, and function by delivering signals to cells, tissues, muscles and other organs, such as:

• Nerves send signals to the skin when to feel
• Nerves send signals to muscles on when to move
• Nerves send signals to the organs or organ systems when to function

For example:

If we touch something hot, our nerves instantly send a message to our brain, which quickly tells us to withdraw our hand.

Thus, the nervous system plays a fascinating role by keeping us safe, helping us to think, and allowing us to experience the world around us!

Conditions and Disorders: What are Common Conditions or Disorders that Affect the Nervous System?

The nervous system is called the command centre of the human body, which is mainly composed of our brain, spinal cord and nerves. The nervous system functions by controlling both the voluntary and involuntary activities in our body.

Certain conditions and nervous system disorders can affect the functioning of our nervous system, causing problems with movement, memory, or even emotions. 

Here are some of the most common nervous system diseases:

Stroke:

This happens when the blood flow to the brain is blocked, causing brain cells to stop working. It can lead to difficulty in speaking, moving, or remembering things.

Epilepsy:

A condition that causes seizures, which are sudden bursts of electrical activity in the brain. This can make a person lose control of their body for a short time.

Meningitis:

An infection that causes swelling in the brain and spinal cord. It can be very serious and needs immediate medical attention.

Parkinson’s Disease:

This affects movement and balance, making simple tasks like writing or walking difficult over time.

Alzheimer’s Disease:

A condition that affects memory and thinking, usually in older people. It can make remembering names, places, or even loved ones very hard.

These are just a few examples of common conditions or nervous system diseases that affect the Nervous System.

Since the nervous system is delicate, many factors such as injuries, infections, and even stress can affect its functioning process. 

Hence, it is always recommended to stay physically active, including a healthy or balanced diet and nutritious food, adequate sleep and staying stress-free for a healthy brain and nervous system.

Key Facts about the Nervous System

Fact No. 1: A human brain needs a lot of blood and oxygen. About 20% of the blood pumped by our heart goes to the brain

Fact No. 2: Axons and dendrites vary in size, but axons are generally longer, and sometimes an axon can be up to a meter long

Fact No. 3: The human brain contains approximately 86 billion nerve cells or neurons. As people get older, they have fewer nerve cells in their brain

Fact No. 4:  Neurons receive signals in a short antenna-like part called the dendrite, and send signals to other neurons with a long cable-like part called the axon

Fact No. 5: Older people are more likely to remember recent events or learning new things, and this is mainly because of the fewer nerve cells in their brain

Fact No. 6: Our brain is like the central processing unit (CPU) in a computer, our spinal cord is a long tube of nerves like a thick electrical cable, and our nerves are like signal wires

Fact No. 7: Our body comprises billions to trillions of nerve cells, among which our brain comprises 100 billion nerve cells, and the spinal cord is composed of  13.5 million nerve cells

Fact No. 8: Our central nervous system resembles a tree trunk that contains the brain and spinal cord. The branches are our peripheral nervous system. These branches extend from the trunk, i.e. from the brain and spinal cord, to reach all parts of your body. 

Fact No. 9: According to recent research, Scientists are developing ways to “hack” into the human nervous system, gaining the ability to control brain cells with a flash of light. However, it should be noted that these studies were performed using mouse cells only.

*Source

Also Read: The Facts about the Digestive System.