B5: Nervous system Flashcards
What two parts does the nervous system consist of ?
1) The Central nervous system (CNS), this consists of the brain and spinal cord.
2) Nerve cells going to and from the CNS.
What is a key role of the nervous system?
Is to enable humans to react to their surroundings and co-ordinate their behaviour. One way this is done is via the reflex arc.
What is the order of the in the nervous system?
1) Stimulus.
2) Receptor.
3) Sensory neurones.
4) Relay neurone which is inside the CNS.
5) Motor neurones.
6) Effector.
7) Response.
What is the function of the sensory neuron?
Carries information as electrical impulses from the receptors.
What is the function of the relay neuron?
Carries electrical impulses from sensory neurones to motor neurons. They are found in the CNS.
What is the function of the motor neuron?
The neurons that carry electrical impulses from the central nervous system to the effectors.
What is a synapse?
Its the gap/junction between two neurones.
How are the nerve signals transferred through the synapse?
The nerve cell signal is transferred through diffusion of chemicals across the gap.
Why are neurones able to deliver information quickly?
The signal is transmitted by electrical impulses.
What is a reflex?
Fast, automatic response to certain stimuli.
Go back to video regarding reflexes bypassing brain.
Why are reflexes important?
Reflexes can reduce your chances of being injured.
What is the reflex arc?
Its the passage of information in a reflex (from the receptor to effector).
Where do neurones in the reflex arc go through?
1) Spinal cord
OR
2) Unconscious part of the brain.
What are the main stages of the reflex arc?
1) When a stimulus is detected by receptors impulses are sent along a sensory neurone to a relay neurone in the CNS.
2) When the impulses reach the synapse between the sensory neurones and relay neurone, they trigger chemicals to be released. These chemicals impulses to be sent along the relay neurone.
3) When the impulses reach a synapse between the relay neurone and motor neurone, the same thing happens. Chemicals are released and cause impulses to be sent along the motor neurone.
4) The impulses then travel along the motor neurone to the effector (which is usually a muscle).
5) If the effector is a muscle, it will respond to impulse by contracting. If its a gland it will secrete a hormone.
