Title: Responding to Change
Learning
Objectives
Why do you need a nervous system?
Starter:
 Complete the following past exam question:
What is a receptor?
How do you respond to changes in your surroundings?
Key Words: stimuli, receptors, impulses, sense organs, CNS, neurons, nerves, secretory organs

The Nervous System
Learning
Objectives
Why do you need a nervous system?
• The primary goal of the nervous system is to enable you to react to your surroundings and co-ordinate your behaviour.
What is a receptor?
How do you respond to changes in your surroundings?
Key Words: stimuli, receptors, impulses, sense organs, CNS, neurons, nerves, secretory organs

The Nervous System
Learning
Objectives
Why do you need a nervous system?
• Changes in your surroundings (stimuli) are picked up by cells known as receptors
What is a receptor?
How do you respond to changes in your surroundings?
Key Words: stimuli, receptors, impulses, sense organs, CNS, neurons, nerves, secretory organs

The Nervous System
Learning
Objectives
Why do you need a nervous system?
• Receptor cells are clustered together in special sense organs, like your eyes or skin.
What is a receptor?
How do you respond to changes in your surroundings?
Key Words: stimuli, receptors, impulses, sense organs, CNS, neurons, nerves, secretory organs

The Nervous System
Learning
Objectives
Why do you need a nervous system?
What is a receptor?
How do you respond to changes in your surroundings?
Key Words: stimuli, receptors, impulses, sense organs, CNS, neurons, nerves, secretory organs

Learning
Objectives
Why do you need a nervous system?
How Your Nervous System Works
• Once a sensory receptor detects a stimulus, the information is sent in the form of an electrical impulse along cells known as neurons.
What is a receptor?
How do you respond to changes in your surroundings?
Key Words: stimuli, receptors, impulses, sense organs, CNS, neurons, nerves, secretory organs

Learning
Objectives
Why do you need a nervous system?
How Your Nervous System Works
• Neurons are usually arranged in bundles of round a thousand, known as a nerve.
What is a receptor?
How do you respond to changes in your surroundings?
Key Words: stimuli, receptors, impulses, sense organs, CNS, neurons, nerves, secretory organs

Learning
Objectives
Why do you need a nervous system?
How Your Nervous System Works
• The impulse travels along the nerve until it reaches the central nervous system
(CNS)
What is a receptor?
How do you respond to changes in your surroundings?
Key Words: stimuli, receptors, impulses, sense organs, CNS, neurons, nerves, secretory organs

How Your Nervous System Works
Learning
Objectives
Why do you need a nervous system?
What is a receptor?
How do you respond to changes in your surroundings?
• Sensory Neurons carry nerve impulses from receptors in the body to the CNS.
• Motor Neurons carry nerve impulses from the CNS to the rest of the body
Key Words: stimuli, receptors, impulses, sense organs, CNS, neurons, nerves, secretory organs

Learning
Objectives
Why do you need a nervous system?
How Your Nervous System Works
• Impulses that travel along motor neurones cause effector organs like muscles or glands to respond.
• Muscles contract and glands secrete chemical substances.
What is a receptor?
How do you respond to changes in your surroundings?
Key Words: stimuli, receptors, impulses, sense organs, CNS, neurons, nerves, secretory organs

Task
Learning
Objectives
Why do you need a nervous system?
1. Your ........ system carries fast....... impulses. Changes in the .............. are picked up by your................
What is a receptor?
How do you respond to changes in your surroundings?
2. Complete:
Receptor  ___  CNS  ___  Effector
3. Explain what happens in your nervous system when you see a piece of chocolate and eat it.
Key Words: stimuli, receptors, impulses, sense organs, CNS, neurons, nerves, secretory organs