Topic 5a- The nervous system Flashcards
What is the function of the nervous system?
The nervous system and hormones enable us to respond to external changes. They also help us to control conditions inside our bodies.
What makes up the central nervous system?
Brain and spinal cord.
What are stimuli?
Changes in the environment.
What are receptors?
Cells that detect stimuli.
What is a nerve impulse?
An electrical signal that passes along a neuron.
What is a nerve impulse?
An electrical signal that passes along a neuron.
What are neurones?
Nerve cells.
What are some ways that a neurone is specialised to suit its function?
Very long so nerve impulses can travel quickly to different parts of the body.
Branched ends to form connections with many other neurones.
Insulating sheath to maintain the nerve impulse.
What are the stages in the nervous system from stimulus to response?
Stimulus
Receptor
Sensory neuron
Co-ordinator (CNS)
Motor neurone
Effector
Response
What are synapses?
Junctions between nerve cells.
What happens when a nerve impulse reaches the end of a neurone?
Chemicals are released that diffuse across the synapse and cause a new nerve impulse in the next neurone.
Explain how a reflex arc works.
A receptor responds to a stimulus (for example finger pricking a cactus).
A sensory neuron sends the nerve impulse to the spinal cord that sends a response back through a motor neurone which causes the effector to act (in this case a muscle in the hand pulling away from the cactus).
