Human Biology - The Nervous System Flashcards
What are your sense organs?
The five sense organs are your eyes, ears, nose, tongue and skin.
What do sense organs do?
Sense organs detect stimuli.
What is a stimulus?
A stimulus is a change in your environment which you may need to react to.
Stimuli include light, sound, touch, pressure, pain, chemical, or a change in position or temperature.
What are receptors?
Receptors are groups of cells which are sensitive to a stimulus. They change stimuli into electrical impulses.
What receptors do these sense organs have? Eyes Ears Nose Tongue Skin
Light receptors Sound and balance receptors Smell receptors Taste and chemical receptors Touch, pressure, pain and temperature change receptors
What are the nerve cells called that carry signals as electrical impulses from the receptors in the sense organs to the central nervous system?
Sensory neurones
What are the tiny nerve cells called that carry signals from sensory neurones to motor neurones?
Relay neurones
What are the nerve cells called that carry signals from the central nervous system to the effector muscles or glands?
Motor neurones
What are the muscles and glands known as?
Effectors. These respond in different ways. Muscles contract in response to a nervous impulse, whereas glands secrete hormones.
What do synapses do?
Synapses connect neurones
How is the nerve signal transferred?
The nerve signal is transferred by chemicals which diffuse across the gap. These chemicals then set off a new electrical impulse in the next neurone.
What are reflexes?
They are automatic responses to a certain stimuli
What is the main reason for reflexes?
Reflexes help to prevent injury
What would your reflexes do if somebody shone a bright light in your eyes?
Your pupils would automatically get smaller so that less light gets into your eye, this stops it form getting damaged.
What is the passage of information in a reflex from a receptor to an effector called?
A reflex arc
