The Nervous System (general) Flashcards
PNS
Peripheral nervous system consists of everything else
CNS
Central nervous system consists of spine & brain
Nervous system
Vast network of nerves in body
Nerve
Bundle of many neurones
Neurone
A cell specialised to generate and conduct electrical impulses from one part of the nervous system to another
Axon
The extension of a neurone that transmits the signal
Brain
Control centre of CNS
Stimulus
A detectable change in the environment
Receptor
A cell that senses a stimulus and starts transmission of the impulse
Sense organ
A specialised organ with clusters if receptor cells
Sense
A system or mechanism in the body that perceives a change
Nerve impulse
Information in the form of an electrochemical signal that travels through a neurone
Effector
Organ that brings about a response
Spinal cord
A bundle of nerves enclosed in the spine; connects nearly all parts of the body to the brain
Coordination
Stimulus - receptor - coordinator - effector - response
Cell body
The part of a neurone which contains the nucleus
Dendrites
Extensions which receive nerve impulses from other cells; the nerve impulses are then transmitted towards the cell body
Axon
Carries nerve impulses to an effector organ (muscle or gland)
Myelin sheath
Fatty sheath which insulates the axon (preventing short circuits of electrical impulses) and speeds up the conduction of nerve impulses
Motor neurone
Transmits impulses from the CNS to the effectors (muscle or gland)
Sensory neurone
Transmits impulses from receptors/sense organs to the CNS
Relay neurone
Within the CNS, transmits impulses from neurone to neurone
Synapses simplified
5
1-impulses arrive down axon of first neurone
2- neurotransmitter diffuses across synapse
3- neurotransmitter attaches to membrane of second neurone
4- impulse started in second neurone
5- neurotransmitter broken down by enzyme from second neurone
