B3.1.1 - Nervous System Flashcards
How does your nervous system work?
By detecting changes in your external environment and sending this information to your brain where it is processed and an appropriate response is created
What is the change of environment in the nervous system?
Stimulus
What are the groups of cells that detect the stimulus?
Sensory receptors
What is the response in a nervous system caused by?
Effectors
What are effectors?
Muscles or glands - muscles respond to an impulse by contracting, while glands react by releasing hormones
Where are your receptor cells found?
In your sense organs
Do all receptors detect all stimuli?
No, different receptors detect different stimuli
What do receptors do?
They change the stimulus into electrical impulses
Where do the electric impulses made by the receptors travel to?
The central nervous system (CNS)
What does CNS stand for?
The central nervous system
What is the CNS made up of?
The brain and the spinal cord
What would receptor cells be for skin?
Pressure and temperature
What would receptor cells be for a nose?
Smell and taste
What would the stimulus be for a tongue?
Chemical
What are the 3 different types of neurones?
Relay, sensory and motor
What do sensory neurones do?
Carry electrical impulses from receptor cells to the CNS
What do relay neurones do?
Carry electrical impulses from sensory neurones to motor neurones
What do motor neurones do?
Carry electrical impulses from the CNS to effectors
What are nerves?
Bundles of hundreds or thousands of neurones
What is the direction of impulse in a sensory neurone?
Left to right
What is the direction of impulse in a relay neurone?
Dendrites to axon
What is the direction of impulse in a motor neurone?
Left to right
What are the steps involved in a coordinated nervous reaction?
Stimulus -> Receptor Cells -> Sensory Neurone -> Spinal Cord -> Brain -> Spinal Cord -> Motor Neurone -> Effector -> Response
How long does a coordinated nervous reaction last?
0.7 seconds
