2.1 Resonding for change

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

How Your Nervous System Works Learning Objectives Why do you need a nervous system?

• 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

How Your Nervous System Works Learning Objectives Why do you need a nervous system?

• 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

How Your Nervous System Works Learning Objectives Why do you need a nervous system?

• 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

How Your Nervous System Works Learning Objectives Why do you need a nervous system? What is a receptor?

• Impulses that travel along motor neurones cause effector organs like muscles or glands to respond. • Muscles contract and glands secrete chemical substances.

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? What is a receptor? How do you respond to changes in your surroundings?

1. Your ........ system carries fast....... impulses. Changes in the .............. are picked up by your................ 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