How Neurons Communicate ?

Content Standards

In this lesson, students will understand the structure and function of neurons, the basic unit of the neural system. They will also explore how action potentials are generated and transmitted.

Performance Standards

Students will be able to:

Identify parts of a neuron and their functions.
Differentiate neuron types and axon types.
Explain nerve impulse generation and transmission.
Apply concepts to reflex actions and daily life.

Alignment Standards

Reference: NCERT Book Alignment

The lesson is aligned with the NCERT Grade 11 Biology Textbook, Chapter 18: Neural Control And Coordination, Section: 18.3 – Neuron As Structural And Functional Unit Of Neural System.

Learning Objectives

By the end of the lesson, students will be able to:

Describe the structure and function of neurons.
Differentiate between multipolar, bipolar, and unipolar neurons.
Explain resting potential, depolarisation, and action potential.
Understand synaptic transmission.
Apply the concept to real-world scenarios.

Prerequisites (Prior Knowledge)

Knowledge of cell structure.
Basic understanding of ions and diffusion.

Introduction

In this session, students will explore neurons, the structural and functional units of the nervous system. Through real-life examples and visual models, they will learn how neurons transmit signals to control thoughts, actions, and body functions.

Timeline (40 Minutes)

Title	Approximate Duration	Procedure	Reference Material
Engage	5	Ask: “Why does your hand instantly pull back when you touch something hot?” Show a diagram of a neuron and prompt: “What could be carrying this message inside your body?” Lead-in: “Let’s discover how neurons communicate with signals.”	Slides
Explore	10	Hands-on: Provide neuron diagrams/cut-outs. Ask students to label parts (cell body, dendrites, axon). Compare multipolar, bipolar, and unipolar neurons using visuals. Pair activity: Students discuss how signals might travel along these structures.	Slides
Explain	10	Explain: Structure of a neuron and its parts. Differentiate: Myelinated vs non-myelinated axons. Show: Resting potential (Na⁺-K⁺ pump), depolarisation, and action potential with diagrams. Demonstrate with VR Lab video: Students watch how electrical impulses move along the axon and jump at nodes of Ranvier, as well as how neurotransmitters transmit signals across synapses.	Slides and Virtual Lab
Evaluate	10	Students will attempt the Self Evaluation task on LMS.	Virtual Lab
Extend	5	Think–Pair–Share: “What happens if signal transmission fails?”	Slides

How Neurons Communicate ?

Introduction

In this lesson, students will explore neurons, the basic building blocks of the nervous system. Neurons are responsible for carrying messages in the form of electrical impulses. By studying their structure and working, we will understand how our brain communicates with the rest of the body, how reflexes happen instantly, and how thoughts and actions are controlled.

Theory

Why Neurons?

Imagine you touch a hot plate—within a second, you pull your hand back.

How does this happen so quickly?
It’s because neurons instantly transmit signals from your skin to your brain and then back to your muscles. This shows neurons are essential for sensing, thinking, and reacting.

What is a Neuron?

A neuron is the basic structural and functional unit of the nervous system. It helps in receiving, processing, and transmitting information through electrical and chemical signals. Neurons are excitable cells that generate nerve impulses and transmit them to other neurons, muscles, or glands.

The structure of a neuron has three main parts:

Cell Body (Soma): Contains the nucleus, cytoplasm, organelles, and Nissl’s granules (for protein synthesis).
Dendrites: Branch-like extensions that receive impulses and carry them towards the cell body.
Axon: A long fibre that carries impulses away from the cell body. It ends in synaptic knobs containing neurotransmitters.

Types of neurons:

Multipolar: One axon, many dendrites (e.g., cerebral cortex).
Bipolar: One axon, one dendrite (e.g., retina).
Unipolar: Only one process (mostly in embryos).

Types of axons:

Myelinated fibres: Wrapped with Schwann cells forming a myelin sheath; gaps are called Nodes of Ranvier. Found in spinal and cranial nerves.
Unmyelinated fibres: Covered by Schwann cells but no myelin sheath. Found in the autonomic and somatic nervous systems.

Generation and Conduction of Nerve Impulse

Neurons are excitable cells because they can change their electrical state.

Resting State (Polarisation):

Outside of the axon = positive charge (high Na⁺).
Inside of the axon = negative charge (high K⁺ and proteins).
Maintained by Sodium-Potassium Pump (3 Na⁺ out, 2 K⁺ in).
This difference is called Resting Potential.

Action Potential (Impulse):

When a stimulus is applied at a point (Fig. 18.2, Point A), sodium channels open.
Na⁺ rushes inside, reversing the polarity (inside becomes positive).
This reversal = Depolarisation = Nerve Impulse.
The impulse moves step by step along the axon as depolarisation travels forward.
Behind each impulse, K⁺ ions move out to restore the resting potential.

Thus, the nerve impulse is like a wave of depolarisation travelling down the axon.

Transmission of Impulses

How does one neuron pass its message to the next? Through synapses.

Types of Synapses:

Electrical Synapse: Direct flow of current; very fast but rare in humans.
Chemical Synapse: More common; uses neurotransmitters.

Process at a Chemical Synapse:

An action potential reaches the axon terminal.
Vesicles release neurotransmitters into the synaptic cleft.
These bind to receptors on the next neuron’s membrane.
Ion channels open, creating a new impulse in the next neuron.

Fun fact: Depending on the neurotransmitter, the message can either excite or inhibit the next neuron.

Applications / Why is it Useful?

Reflexes: Protect us (like pulling hand away from fire).
Brain-body link: Thinking, learning, and memory all depend on neurons.
Medicine: Helps explain diseases like Multiple Sclerosis (damaged myelin sheath) and Parkinson’s.

Technology: Neurons inspire Artificial Neural Networks (ANNs) in Artificial Intelligence.

Vocabulary

This is the list of vocabulary terms used throughout the lesson.

Neuron: Microscopic nerve cell that transmits electrical and chemical signals.
Cell Body (Soma): Main part of the neuron containing the nucleus and Nissl’s granules.
Dendrites: Branch-like structures that receive information.
Axon: Long fibre that carries messages away from the cell body.
Synapse: Junction between two neurons where communication happens.
Neurotransmitters: Chemicals that pass signals across synapses.
Resting Potential: Electrical difference across the neuron’s membrane when not active.
Action Potential: Electrical impulse that travels along the axon.
Myelin Sheath: Fatty layer around some axons that speeds up signal transmission.
Nodes of Ranvier: Gaps between myelin sheaths that help the impulse jump faster.

How Neurons Communicate ?

Introduction

In this activity, students will explore how neurons transmit information in the nervous system. They will watch animated simulations of nerve impulses, action potentials, and synaptic transmission to understand how the brain and body communicate.

Key Features

Animated simulation of how signals travel along a neuron
Visualisation of action potentials moving through the axon
Demonstration of synaptic transmission (neurotransmitters crossing the synaptic cleft)
Connection to body functions – how signals control thoughts, movements, and actions
Observation-based learning – no manual adjustments required
Embedded short quiz (2 MCQs) for quick reinforcement

Step-by-Step Procedure for VR Experience

Open the Virtual Lab
Access the simulation link provided to begin the activity.
Watch the Action Potential
View how a nerve impulse begins as an action potential and travels along the axon.
Observe Polarity Changes
Notice how the membrane depolarises and repolarises as the signal moves forward.
See Synaptic Transmission
Watch how neurotransmitters are released at the synapse and received by the next neuron.
Follow the Neural Network
Observe how impulses continue across neurons to connect the brain and the body.
Connect to Real-Life Functions
Understand how these signals control everyday functions like movement, reflexes, and thoughts.
Take the Quiz
Attempt the 2 MCQs embedded in the lab to check your understanding.
View Results
See your score instantly as feedback and reinforcement.