The Nervous System & Reflexes Flashcards
What does the nervous system do
It detects and reacts to stimuli
Why do multicellular organisms develop nervous and hormonal systems
So the cells of the multicellular organisms can communicate with each other first
What are the 4 parts of the nervous system
Central nervous system
Sensory neurones
Motor neurones
Effectors
What are the central nervous systems in vertebrates and in mammals
Vertebrates = the brain and the spinal cord only Mammals = the cns is connected to the body by sensory neurones and Motor neurones
What is the sensory neurones
The neurones that carry information as electrical impulses from the receptors to the cns
What are motor neurones
The neurones that carry electrical impulses from the cns to the effectors
What are the effectors and what do they do
All the muscles and glands in the body which respond to the nervous impulses
What are receptors and give some examples
They are the cells which detect stimuli
Taste receptors on the tongue
Sound receptors in the ears
What are effectors
They respond to nervous impulses and being about change
Give examples of effectors and what they do
Muscles = contract in response Glands = secrete hormones in response
What does the coordination’s centre (central nervous system) do
It coordinates a response
It will receive info from the receptors and then decides what to do then the response is carried out by the effectors
Give the order of what happens in the nervous system
Stimulus Receptor Sensory neurone CNS motor neurone Effector Response
What is a synapse
The connection between 2 neurones
What happens in a synapse
The nerve signal is transferred by chemicals which diffuse across the gap
These diffused chemicals then set off a new electrical signal in the next neurone
What’s quicker
Neurones or reflexes
Reflexes
What are reflexes
Rapid automatic responses which don’t involve the conscious part of the brain
What do reflexes help prevent
Injury
What is the passage of information in a reflex (from receptor to effector) called?
A reflex arc
In a reflex how are chemicals sent along the relay neurone
When the impulse from a stimulus reach a synapse between the sensory neurone and a relay neurone, they trigger chemicals to be released, these chemicals cause the impulses to be sent along the relay neurone
What do relay neurones connect and what does this mean
The sensory neurone and the motor neurone
The relay neurone goes through the cns (bypasses it completely) so you don’t have to think about the response
Therefore relay neurones make the response quicker
What reaction time test gives a more precise and accurate result and why is this
The computer test because the remove the possibility of human error and they can record the reaction time in millisecond
