Reflex Actions Flashcards
Why are reflexes important
They help to avoid danger or harm because they happen so fast. There are also lots of reflexes that take care of your basic body functions like breathing and food moving through the gut
Describe the pathway of a reflex arc from stimulus to response
Stimulus-receptor-sensory neurone-relay neurone-motor neurone- effector- response
What is a reflex
An automatic response to certain stimuli.
To reduce chance of injury
What is the passage of information in a reflex from receptor to effector called
Reflex arc
Describe the reflex arc in more detail
1) Bee stings finger
2) stimulation of the pain receptor
3) impulses travel along the sensory neurone
4) impulses are passed along a relay neurone via a synapse
5) impulses travel along a motor neurone via a synapse
6) when impulses reach muscle it contracts
Reflex arc and nervous system
The neurones in reflex arc go through the spinal cord or through an unconscious part of the brain.
When a stimulus is detected by receptors, impulses are sent along a sensory neurone to the CNS
When the impulses reach a synapse between the sensory neurone and a relay neurone, they trigger chemicals to be released. These chemicals cause impulses to be sent along the relay neurone.
When the impulses reach a synapse between the relay neurone and a motor neurone, the same thing happens chemicals are released and cause impulses to be sent along the motor neurone
Impulses them travel along the motor neurone to the effector
If it’s a muscle it then contracts and moves your hand away from the bee
Because you don’t have to think about the response which takes time it’s quicker than a normal response
Synapses connect neurones
The connection between two neurones is called a synapse.
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
