8.1 - The nervous system and nerve impulses Flashcards
what part of the nervous system is the autonomic and somatic nervous system part of?
peripheral nervous system
what part of the nervous system is the sympathetic and parasympathetic nervous system part of?
autonomic nervous system
what part of the nervous system imitates a fight or flight response?
the sympathetic nervous system
what three structures do all neurones have?
a cell body, dendrites and an axon
what is the structure of a sensory neurone?
dendrites on both ends and cell body is located on the side of the axon
what is the structure of a relay neurone?
dendrites at both ends and cell body in the middle of the axon
what is the structure of a motor neurone?
cell body at the end of the axon with dendrites attached and dendrites at the other side
what to sensory neurones receive impulses from and where are they transmitted to?
from the sensory cells to the CNS
where are relay neurones found?
in the CNS
what to motor neurones receive impulses from and where are they transmitted to?
from the CNS to effectors
what is an adaptation of dendrites?
they are highly branched to conduct nerve impulses from many other neurones
what is an adaptation of the axon?
they are long to transmit impulses over a long distance and also covered in lipid to ensure the signal travels in one direction
what two muscles control the size of the pupil?
radial and circular
are radial muscles the sympathetic or parasympathetic reflex?
sympathetic
are circular muscles the sympathetic or parasympathetic reflex?
parasympathetic
what is the refractory period and why is it needed?
it is a break between action potentials and it ensures impulses travel in one direction
what changes the intensity of a stimulus?
the frequency of impulses and the number of neurones in a nerve conducting impulses
what are two types of synapse?
excitatory and inhibitory
what is summation?
the build up of sufficient concentrations of neurotransmitter to cause the threshold value to be exceeded to generate an action potential
what is spacial summation?
when multiple pre-synaptic neurones each release neurotransmitter
what is temporal summation?
a single pre-synaptic neurone releases neurotransmitter multiple times
give an example of an auxin
IAA
what does IAA cause?
cell elongation and inhibits root growth
