Nervous system Flashcards
Name stimuli?
Light, chemicals, sound, touch, pain and changes in temperature
What is a receptor?
A special sensory cell that detects change in environment
What is meant by stimuli?
A change in the environment which is detected by sensory receptors
Why is it important the nervous system can detect stimuli?
To react/respond (to the surroundings)
Prevent harm to body (avoid danger)
To coordinate behaviour/ process information
What are sense organs?
Organs that contain receptors that are sensitive to stimuli
What is meant by neurons?
Nerve cells that carry information as electrical pulses around the body?
What are sensory neurons?
Carry impulses from receptors to CNS
What are relay neurons?
Carry impulses from one part of the CNS to another
What are motor neurons?
Carry impulses from the CNS to effector organs
Suggest how the reflex action of the eye to bright light useful to the body?
Reduces / controls amount of light entering the eye
So there is a less of a chance of damage
How do the impulses travel from the receptor to the CNS?
As electrical impulses along a sensory neuron
Describe how information passes from the relay neurone to the motor neurone?
A chemical is released from a relay neurone
Chemical diffuses across a synapse gap
Chemical attaches to motor neuron causing impulses
What do light receptors contain?
Nucleus
cell membrane
cytoplasm
Summary of the nervous system?
Receptor Sensory neurone Coordinator (CNS) Motor neuron Effector
Describe differences between a reflex action and a voluntary action?
Faster Automatic (not thought about) Involve fewer neurones Involves fewer synapses Does not always involve the brain
