Nervous system Flashcards
There are two types of reactions. Name them.
Reflex action and a conscious action
What is a reflex action?
A reflex action is when the body needs to react quickly to the stimuli so when sending the electrical impulse through the sensory neurone it bypasses the brain and goes to the spinal cord instead which then sends a quick message back.
In reflex actions does the brain take time to think about what to do?
No. The reaction to the stimuli is so quick that there is no thought e.g. If there was a hot flame you’d pull your hand away without thinking about it.
Name the five receptors.
Tongue, eyes, nose, skin, ears
what stimuli do the eyes detect
light
what stimuli does the tongue detect
chemicals
what stimuli do the ears detect
sound and orientation
what stimuli does the skin detect
pain, temperature and pressure
what stimuli does the nose detect
chemicals
what are the three main parts of a nerve cell
nucleus, cytoplasm and cell membrane
where do the sensory neurones carry signals from and to
from the receptors to the spinal cord and brain
where do the motor neurones carry signals from and to
from the spinal cord and brain to the effector
where do the relay neurones carry messages to and from
carry messages from one part of the CNS to another
what is a synapse
the gap between two nerves where the chemicals have to diffuse across to pass the message on.
state a simple reflex action
stimulus- receptor- sensory neurone- relay neurone- CNS- motor neurone- effector- response