Nervous System Diagram Explanation

Introduction to the Nervous System

The nervous system is the control and communication system of the human body. It receives information from the surroundings, processes it, and sends responses to different body parts.

According to NCERT, the nervous system helps organisms react to changes in the environment through coordination and control.

Main Functions of the Nervous System

Receives information through sense organs
Processes information in the brain
Sends instructions to muscles and glands
Controls voluntary and involuntary activities
Maintains coordination in the body

Nervous System Diagram (Human)

Components of the Nervous System

Component	Function
Brain	Control center of body
Spinal Cord	Transfers messages
Nerves	Carry impulses
Neurons	Structural and functional unit

1. Central Nervous System (CNS)

The Central Nervous System consists of:

Brain
Spinal Cord

Its function is:

Processing information
Decision making
Controlling body activities

Diagram of Central Nervous System

2. Brain – Structure and Explanation

The brain is protected by:

Skull
Cerebrospinal fluid

The brain has three major parts.

A. Forebrain (Cerebrum)

Functions:

Thinking
Memory
Intelligence
Voluntary actions
Interpretation of sensory information

B. Midbrain

Functions:

Controls visual and auditory reflexes

C. Hindbrain

Functions:

Balance
Posture
Involuntary actions

Includes:

Cerebellum
Medulla
Pons

Diagram of Brain

3. Peripheral Nervous System (PNS)

This system connects:

Brain
Spinal cord
Entire body

Functions:

Carries messages between CNS and body

Two divisions:

Sensory Nerves

Carry information to CNS

Motor Nerves

Carry response from CNS

4. Neuron – Basic Unit of Nervous System

Neuron is the structural and functional unit of the nervous system.

Parts of Neuron

Part	Function
Dendrites	Receive impulse
Cell Body	Processes signal
Axon	Transfers impulse
Axon Terminal	Passes message

Diagram of Neuron

Working of Nervous System

Step 1: Stimulus

Change occurs in surroundings.

↓

Step 2: Receptors

Sense organs detect change.

↓

Step 3: Sensory Neuron

Message travels to brain.

↓

Step 4: Brain Processing

Decision is made.

↓

Step 5: Motor Neuron

Signal sent to muscles.

↓

Step 6: Response

Action occurs.

Reflex Action and Nervous System

Reflex action:

Immediate response
Controlled by spinal cord
Faster than normal response

Example:

Pulling hand away from hot object

Reflex Arc

Important NCERT Points

Neuron is the structural and functional unit.
Brain is protected by skull.
Reflex action occurs through spinal cord.
Nervous system coordinates body activities.
Messages travel as electrical impulses.

Practice Questions with Answers

1. What is the nervous system?

Answer: The nervous system is the body’s control and coordination system.

2. Name the parts of CNS.

Answer: Brain and spinal cord.

3. Which part controls balance?

Answer: Cerebellum.

4. What is a neuron?

Answer: Structural and functional unit of nervous system.

5. What controls reflex action?

Answer: Spinal cord.

Fill in the Blanks

The __________ is the control centre of the body.
Answer: Brain
__________ carries messages throughout the body.
Answer: Nerves
Reflex action is controlled by __________.
Answer: Spinal cord
The basic unit of nervous system is __________.
Answer: Neuron
__________ receives signals.
Answer: Dendrites

MCQs (with Answers)

1. Functional unit of nervous system is:

A. Blood
B. Neuron
C. Bone
D. Muscle

Answer: B

2. Which controls intelligence?

A. Cerebrum
B. Medulla
C. Spinal cord
D. Nerve

Answer: A

3. Reflex action is controlled by:

A. Brain
B. Heart
C. Spinal cord
D. Kidney

Answer: C

4. Which receives impulse?

A. Axon
B. Dendrite
C. Muscle
D. Bone

Answer: B

5. CNS stands for:

A. Central Nervous System
B. Cell Nervous System
C. Controlled Nerve Signal
D. Central Neural Section

Answer: A

6. Brain is protected by:

A. Skin
B. Skull
C. Bone marrow
D. Muscle

Answer: B

7. Peripheral nervous system connects:

A. Body to CNS
B. Bone to muscle
C. Skin to blood
D. Heart to lungs

Answer: A

8. Which controls posture?

A. Hindbrain
B. Liver
C. Kidney
D. Stomach

Answer: A

9. Messages travel as:

A. Hormones
B. Electrical impulses
C. Air
D. Water

Answer: B

10. Sense organs detect:

A. Stimulus
B. Blood
C. Food
D. Bone

Answer: A

Summary

The nervous system is responsible for control, coordination, communication, thinking, movement, and responses in the human body. It consists of the brain, spinal cord, nerves, and neurons working together to process information and produce actions.