Nervous System Flashcards
What is homeostasis?
Homeostasis is the maintenance of a constant internal environment.
Example of homeostasis
Examples include blood glucose, water levels and body temperature.
What do all control systems have?
Receptors
Coordination centres
Effectors
What is a Receptor
cells that detect stimuli
What is a coordination centre?
process information given by the receptors
Example of a coordination centre
Brain
Spinal cord
Pancreas
What is an effector?
bring about responses to bring the conditions in the body back to optimum levels
Example of an effector
Muscles
Glands
How does the nervous system help us react and coordinate actions in response to stimuli?
1. Receptor cells convert stimulus in to an electrical impulse
2. Electrical impulse travels along sensory neurons to the CNS
3.Information is processed
4.Appropriate response is coordinated and electrical impulse is sent along the motor neurons to the effector
5. Effectors carry out response
CNS
Central Nervous System
Why are reflex actions different to usual stimuli?
The reflex arc skips out the conscious part of your brain
Example of a reflex
Sharp stimuli
Burning stimuli
Describe the reflex arc
1. Stimulus detected by receptors
2. Impulses are sent along a sensory neuron
3. In the CNS the impulse passes to a relay neuron
4. Impulses are sent along a motor neuron
Neurons
specialised cells that conduct electrical impulses through the body
Nerve
bundle of many nerve fibres enclosed within a protective sheath
Nerve fibres
long axons of neurons together with any associated tissues
Stimulus
Change in environment that prompts receptors
What is the function of the nervous system?
Make quick short term reactions to environment and coordinate behaviour
What is in the peripheral nervous system?
Neurons bundled in to nerves
Parts of CNS
Brain
Spinal cord
What is a synapse?
Gaps between two neurons
How many synapses does the human body have?
500 Trillion
Describe how a synapse completes its function
1. When impulse reaches the end of the first neuron a chemical is released in to the synapse
2. Chemical diffuses across the synapse
3. When the chemical reaches the second neuron it triggers the impulse to begin again in the next neuron
What is reaction time?
How long it takes you to respond to a stimulus
