The Human Nervous System

Parts Of The Nervous System

The human nervous system is like the body’s control center. It sends and receives messages all over the body, allowing you to interact with the world around you. There are two main parts of the nervous system:

• The Central Nervous System (CNS) includes the brain and spinal cord. The brain is like the executive decision-maker, and the spinal cord is like a highway, sending messages between the brain and the rest of the body.
• The Peripheral Nervous System (PNS) is made of nerves that spread from the brain and spinal cord to all body parts. These nerves carry signals from the CNS to your muscles and organs and from your senses (like your eyes, ears, and skin) back to the brain.

 

Messengers Of The Nervous System

The nerve cells, or neurons, are the basic units of the nervous system. 

Neurons have a nucleus or center and two or more long fibers or threads. Electric Impulses travel to and from the neurons along these fibers.

There are two main types of nerves: 

• Sensory Nerves handle information related to the senses and send information from the eyes, ears, mouth, nose, skin, and other body parts to the spinal cord and brain. 
• Motor Nerves carry messages from the brain and spinal cord to muscles and other body parts. Autonomic nerves are a special type of motor nerve. They control the organs inside the body. 

When your brain sends a message, an electrical signal travels along a neuron, jumping from one to another through small gaps called synapses. 

• These signals can move as fast as 100 meters per second (about 224 miles per hour!), allowing you to react almost instantly.
• For example, when you touch something hot, your body pulls away faster than you can blink!
• Nerves are coated in myelin, a special substance that acts like insulation around wires, speeding up the signals.
• This incredible speed is essential to keep the body safe and function smoothly!

 

Fun Facts

Here are some interesting facts about the nervous system:

• The brain has around 86 billion neurons, each sending messages to different parts of your body
• The longest nerve in the body is the sciatic nerve, running from the lower back to the feet.
• A single neuron can send 1,000 signals per second, making it super efficient at communication.
• Babies are born with all the neurons they will ever have, but the connections between them grow as they learn.

 

Review

Let’s quickly recap what we learned about the nervous system:

• What connects the brain to the rest of the body? Spinal Cord
• What carries signals from the brain to other parts of the body? Nerves
• What type of signals do nerves use to send messages? Electrical
• What is the part of the nervous system outside the brain and spinal cord? Peripheral
• What are the small gaps where signals jump from one neuron to another? Synapses