Reflexes L.O: To know what a reflex is and how they work Can you measure your pupil in the light and dark? Remember don’t touch your eye!

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

Co-ordinator: Relay neurone 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? Takes messages from receptors to the brain or spinal cord Motor Neurone: Takes messages from the brain or spinal cord to the muscles and organs

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

Plenary Explain 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 receptor B – Smell receptor C – Pressure receptor D – Light Receptor

3. Which is the neurone which takes impulses from your receptor to your spinal cord? A- Sensory neurone B – Relay neurone C – Connector neurone D - Motor neurone

4. What part of your nervous system is missed in a quick reflex response? A – Relay neurone B – Spinal cord C – Brain D - Effector

5. Which of these stimulus is the correct one for feeling hot water A – Taste B – Light C – Temperature D - Touch

6. Which one of these is not an effector? A – Leg muscle B – Biceps C - Salivary glands D – 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 receptor B – Smell receptor C – Pressure receptor D – Light Receptor

3. Which is the neurone which takes impulses from your receptor to your CNS A- Sensory neurone B – Relay neurone C – Connector neurone D - Motor neurone

4. What part of your nervous system is missed in a quick reflex response? A – Relay neurone B – Spinal cord C – Brain D - Effector

5. Which of this stimulus’s is the correct one for feeling hot water A – Taste B – Light C – Temperature D - Touch

6. Which one of these is not an effector? A – Leg muscle B – Biceps C - Salivary glands D – Ear drum