Unit 2.2 Control and Communication Flashcards
Function of the nervous system
Allows an organism to detect changes in its external and internal environment, analyse and store information and respond to changes.
What are the 2 main parts of the nervous system?
Central nervous system (CNS) and peripheral nervous system (made up of nerves linking the CNS to other areas).
Central nervous system (CNS)
The brain and spinal cord.
Receptors
Specialised cells that detect changes in the internal and external environment.
Receptors detect a stimulus and change it into an electrical signal (impulse) which is sent to the CNS.
Where are receptors found?
They are found in sense organs (eg. photoreceptors in the eye), the skin (pressure, pain and thermoreceptors) and inside the body (eg. stretch receptors in blood vessels and the gut wall).
Brain
A complex organ made of billions of nerve cells.
It interprets electrical signals from other parts of the nervous system and sends out more signals in response.
What are the 3 main areas of the brain?
Cerebrum, cerebellum and medulla.
Cerebrum
Responsible for high level processing - thought, memory, reasoning and intelligence
Medulla
Controls breathing and heart rate.
Cerebellum
Used for muscular co-ordination and balance.
Spinal cord
A bundle of nerve fibres that runs the length of the body from the brain through a hole in each vertebra (back bone).
Electrical signals travel up and down the spinal cord to/from the brain or enter and leave through peripheral (side) nerves during a reflex action.
Nerve
A bundle of nerve fibres wrapped in a protective cover (sheath)
Nerve fibres are bundles of axons (the long fibres of neurons - nerve cells)
Neurons
Specialised nerve cells that carry electrical impulses around the body.
They have long fibres called axons which carry the impulses, and smaller fibres that connect with other neurons.
What are the 3 types of neuron?
Sensory, inter (relay) and motor neurons.
Sensory neuron
Transmits impulses from a receptor to the CNS.
The cell body (containing the nucleus and most of the cytoplasm) is found in the middle of the sensory neuron - off to one side.