The Nervous System Flashcards
What does the PNS include
Nerves outside the CNS
What does the CNS include
The brain and the spinal cord (optic nerve)
Define coordination
The organisation of the different elements of the complex body
Define ‘effector’
An organ (muscle or gland) that brings about a response
Define nervous system
The vast network of nerves in the body
Define receptor cell
A cell that senses a stimulus and transmits the message along
Define stimulus
A detectable change in the environment
Define response
A change brought about following a stimulus
Define the CNS
Do you part of the nervous system that includes the brain, optic nerves and the spinal cord
Define Sense organ
A specialised organ with clusters of receptor cells that sense a change in the environment
Define brain
The control centre of the CNS
Define spinal cord
A bundle of nerves in closed in the spine that connects nearly all parts of the body to the brain
Define reflex
Involuntary and almost immediate response to a stimulus
Define neurone
A nerve cell-a specialised cell which transmits info through nerve impulses
Define nerve
Nerve cell-a single neurone
Nerve - A bundle of several neurons
Define nerve impulse
Electrical signals (current) that travels along a neurone
Define cell body
The part of a neuron which contains the nucleus
Define dendrites
Extensions at which nerve impulses are received from other cells at synapses and transmitted to the cell body
Define axon
Extensions which carry nerve impulses to another neurons or a effector organ (muscle or gland)
Define myelin sheath
Fatty sheath which insulates the axon (preventing short-circuits of electrical impulses) and speeds up the conduction of nerve impulses; made of Schwann cells
Explain the reflex Ark
Stimulus–> receptor–> sensory neuron–> relay neuron (CNS)–> motor neuron –> effector –> response
What are all receptors?
Transducer. When energy is changed from one form into another, this is called transduction. All receptors are transducers of energy.
What is the biological name for a nerve cell
A neuron
What do motor neurones do
Transmit impulses to the muscles and glands
