Can you measure your pupil in the light and dark? Remember don’t

touch your eye!

Reflexes

L.O: To know what a reflex is and how they work

Can you move your body without using your brain?

• What is a reflex?– Reflex action is a rapid automatic and involuntary

response to a stimulus which is not under the control of the brain.

• Can anyone think of any reflexes?– Knee-jerk reflex– Achilles reflex– Touching a hot plate– Coughing– yawning– blinking of eyes – Sneezing– movement of diaphragm during breathing

How could you prove that your brain isn’t coordinating a response?

Nervous system card sort - Sort the cards into a normal nervous system response and a reflex response- Match the example to the sequence

Your brain has no part in this pathways ie reflex arc

Co-ordinator:

Relay neurone

How do reflexes work?

• Video

Label your diagram and explain in your own words how a reflex works, using the words

Stimuli, Receptor, Sensory neuron, Interneuron, spinal cord, motor neuron, muscle, contracts, reflex action

Explain the reflex pathway when you touch a hot tripod

What are the differences between the motor and sensory neurones?

Motor Neurone:• Takes

messages from the brain or

spinal cord to the muscles and organs

Sensory Neurone: • Takes

messages from receptors to the brain or

spinal cord

Neurones join at synapses• Chemicals are secreted

between the gaps• Synapses slow down

impulses, but one neurone can synapse several

• A relay neurone has synapses with a sensory and motor neurone and also those to the brain

How do the following drugs work?

• Paracetamol• Aspirin• Dentists procaine injected into gums• Curare given to patients undergoing surgery to

stop muscles moving

PlenaryExplain what these words mean

• Stimulus• Receptor• Sensory neurone• Relay neurone• Motor neurone• Effector• Response• Reflex arc

1. Which is the correct sequence for a nervous response

A – Stimulus, receptor, co-ordinator, response, effector

B – Receptor, effector, stimulus, co-ordinator, response

C – Stimulus, Receptor, co-ordinator, effector, response

D – Stimulus, effector, co-ordinator, receptor, response

2. Which is the receptor in your eyes?

A – Sound receptorB – Smell receptorC – Pressure receptorD – Light Receptor

3. Which is the neurone which takes impulses from your receptor to your spinal cord?

A- Sensory neuroneB – Relay neuroneC – Connector neuroneD - Motor neurone

4. What part of your nervous system is missed in a quick reflex response?

A – Relay neuroneB – Spinal cordC – BrainD - Effector

5. Which of these stimulus is the correct one for feeling hot water

A – TasteB – LightC – TemperatureD - Touch

6. Which one of these is not an effector?

A – Leg muscleB – BicepsC - Salivary glandsD – Ear drum

Answers

1. Which is the correct sequence for a nervous response

A – Stimulus, receptor, co-ordinator, response, effector

B – Receptor, effector, stimulus, co-ordinator, response

C – Stimulus, Receptor, co-ordinator, effector, response

D – Stimulus, effector, co-ordinator, co-ordiantor, receptor, response

2. Which is the receptor in your eyes?

A – Sound receptorB – Smell receptorC – Pressure receptorD – Light Receptor

3. Which is the neurone which takes impulses from your receptor to your CNS

A- Sensory neuroneB – Relay neuroneC – Connector neuroneD - Motor neurone

4. What part of your nervous system is missed in a quick reflex response?

A – Relay neuroneB – Spinal cordC – BrainD - Effector

5. Which of this stimulus’s is the correct one for feeling hot water

A – TasteB – LightC – TemperatureD - Touch

6. Which one of these is not an effector?A – Leg muscleB – BicepsC - Salivary glandsD – Ear drum