Biology - The Nervous System
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What is the main function of the nervous system?
To react to what’s going on around the organism
The nervous system is made up of lots of what?
Neurones (nerve cells)
What is the function of nerve cells?
To carry an electrical message or impulse when stimulated.
A bundle of neurons is called a what?
A nerve
Neurones go to all parts or only some parts of the body?
All parts
What are receptors?
Cells that detect stimuli and convert to electrical impulses.
What are effectors?
Muscles or glands that respond to nervous impulses
Define stimulus
Something that sets off a reaction in the nervous system, for example, light, heat, sound, gravity, smell, taste, or temperature. These changes in the environment are detected by receptors in an organism. The plural is stimuli.
Give an example of sensory receptors?
Light receptors in eyes detecting light
What is the function of the Central Nervous System (CNS)
To receive and send nervous electrical impulses in response to stimuli
What are the 2 main parts to the Nervous System?
Central Nervous System (CNS) - made of brain and spinal cord Peripheral Nervous System (PNS) - network of nerves outside the brain and spinal cord that connects the central nervous system to the rest of the body, enabling movement, sensation, and involuntary functions.
Name the three main types of neurones:
sensory motor relay
What is the function of the sensory neurone?
Carries impulses from RECEPTORS to the CNS
What is the function of the motor neurone?
Carries impulses from the CNS to EFFECTORS
What is the function of the relay neurone?
Connects sensory and motor neurones and carries through the CNS
Name the 4 parts of a neurone (see p 23 for learning)
1) cell body 2) dendrites 3) dendrons 4) axon
Which 2 parts of the neurone carry nervous system impulses TOWARDS the cell body?
Dendrites and dendrons (d and d)
Which part of the neurone carries nervous system impulses AWAY from the cell body?
Axons
Where would you find the myelin sheath in a cell body?
Surrounding the axons
What is the myelin sheath made up of?
A fatty material
What is the purpose of the myelin sheath?
To speed up electrical impulses.
What type of receptor carries impulses from RECEPTORS to CNS
Sensory neurone
What type of receptor carries impulses from CNS to effectors?
Motor neurone
What type of receptor carries impulses through the CNS?
Relay neurone (think relay race)