Synapses and reflexes
- Created by: ell1e24
- Created on: 19-02-16 20:05
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- Synapses and reflexes
- synapses
- A synapse is the connection between two neurones
- The nerve signal is transferred by chemicals which diffuse across the gap
- these chemicals then set off a new electrical signal in the next neurone
- synapses slow down the transmission of a nervous impulse as the diffusion of chemicals across the gap takes time (although is still fairly quick)
- Reflexes
- they are fast automatic responses to certain stimuli
- bypass your brain when a quick response is essential.
- reduce chance of being injured
- other examples of reflexes being used
- if someone shines a bright light in your eyes, pupils automatically get smaller. Means less light enters your eyes stopping them from being damaged
- if your shocked adrenaline is released automatically It doesn't wait for you to decide if your shocked or scared
- Reflex arcs
- the information in a reflex is called a reflex arc
- the neurones in a reflex arc go through the spinal cord or an unconscious part of the brain
- 1-a stimulus is detected by receptors and impulses are sent along a sensory neurone to the CNS
- 2- when the impulses reach a synapse between the sensory neurone and a relay neurone, they trigger chemicals to be released. It is these chemicals that cause impulses to be sent along the relay neurone
- 2- when the impulses reach a synapse between the sensory neurone and a relay neurone, they trigger chemicals to be released. It is these chemicals that cause impulses to be sent along the relay neurone
- 3-when the impulses reach a synapse between the relay and motor neurone the same thing occurs. Chemicals are released and sent along the motor neurone
- 4-the impulses then travel along the motor neurone towards the effector
- 5-If the effector is a muscle it will contract as a response to the impulse but if it is a gland it will secrete a hormone
- a reflex arc is quicker as you dont have to think about it
- synapses
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