definitions Flashcards
Nervous system
consists of the central nervous system and peripheral nervous system
central nervous system (CNS)
consists of the brain and the spinal chord and is the origin of all complex commands and decisions
peripheral nervous system (PNS)
sends information to the CNS from the outside world and transmits messages from the CNS to muscles and glands in the body
somatic nervous system
transmits information from receptor cells in sense organs to the CNS. It also receives information from the CNS that directs muscles to act
autonomic nervous system
transmits information to and from internal bodily organs. The system operates involuntarily. it has two main divisions: the sympathetic and parasympathetic nervous systems
Neuron
nerve cells that process and transmit messages through electrical and chemical signals
sensory neurons
these carry messages from the PNS to the CNS
relay neurons
These connect the sensory neurons to the motor and other sensory neurons
motor neurons
these connect the CNS to effectors e.g. muscles and glands
synaptic transmission
the process by which neurones communicate by sending neurotransmitters across the synapse between each other
neurotransmitters
brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to the other. They either perform the excitatory function or an inhibitory function
Excitation
when a neurotransmitter increases the positive charge of the post synaptic neuron. This increases the likelihood that the neuron will pass on the electrical impulse e.g. adrenaline
inhibition
when a neurotransmitter increases the negative charge of the post synaptic neuron. This decreases the likelihood that the neuron will pass on the electrical impulse e.g. serotonin
