How do cells in the body communicate?
Success Criteria To use your scientific knowledge to produce a flow chart of the nervous system. To investigate how your body responds to stimulus. To complete a diagram to show the similarities and differences between hormone communication and nervous responses.
Nervous system Parts of our body we use to sense things are called SENSE ORGANS – eye, ear, mouth, skin, nose. Each SENSE ORGAN has special cells called RECEPTOR CELLS. Each receptor cell is sensitive to different things.
Eyes contain light receptors Ears contain sound receptors Mouth and nose contain chemical receptors Skin has receptors for temperature and pressure.
What causes a reaction? A stimulus is something that is detected by a receptor e.g. light, heat, sound. So what happens after the receptor detects the stimulus? What causes a reaction to happen?
The main part of our nervous system is called the Central Nervous system. The central nervous system is made up of the brain and spinal cord. Spinal cord cross section
Neurons are like messengers Sensory neurone Motor Neurone Neurons are like messengers They carry electrical impulses to and from the sensory organs and the spinal cord.
Now you will make a flow chart to describe this process Reflex in the finger Stimulus picked up by Receptor cells in finger (skin) Impulse passed on to sensory neurone Sensory neurone passes impulse to spinal cord Spinal cord sorts out response and sends message to motor neurone Motor neuron tells the finger to pull away Now you will make a flow chart to describe this process
Testing your reflexes A reflex is a response to a stimulus that doesn’t require thinking. This means that the reaction is very fast! Now we are going to do some experiments to look at different responses to stimuli.
Why are reflexes important? Now we have discussed it write a few sentences to explain why it is important that organisms have evolved to be able to respond to stimuli.
Are all responses nervous? No some responses to stimuli are caused by hormonal communication. Hormones are: Chemicals Secreted by glands Carried in the blood stream to target organs
The similarities and differences Nervous response to stimulus Hormonal response to stimulus