Neuronal communication past paper qs Flashcards
Outline the ways in which the structures of a sensory neurone and a motor neurone
are similar
-myelin sheath, axon, cell body containing nucleus, dendrites
. Alcohol causes vasodilation.
Explain why it is not a good idea to give alcohol to someone with hypothermia.
vasodilation results in more blood nearer to the
skin surface ;
2 idea that will lose (even) more heat /
further heat loss (from body) /
body temperature decreases further ;
3 (named) organ(s) will not be able to maintain ,
function / metabolism
Why is the Pacinian corpuscle described as a transducer?
-converts mechanical energy into chemical energy
The generation of an action potential follows the ‘All-or-Nothing’ law.
Explain what this means.
if the , stimulus is not strong enough /
threshold (value) is not reached /
depolarisation (of membrane) is insufficient ,
then , it / an action potential , is not ,
generated
Describe how information about the strength and intensity of a stimulus is communicated
to the brain
idea that it is represented by the frequency of the
action potentials ;
2 high , frequency / rate (of generation) ,
of action potentials shows ,
a strong / an intense , stimulus
Synapses are an integral part of the nervous system.
Outline the roles of synapses in the nervous system
-allows neurones to communicate
-ensures transmission of impulse in one direction
-ensures only large stimuli to be passed on
-allows low level stimuli to be amplified
Name the gap between two adjacent Schwann cells along the length of the neurone
-nodes of ranvier
Outline how the first neurone communicates with the second neurone across the gap
(named) neurotransmitter / acetylcholine , released from
pre-synaptic / first , cell / membrane ;
2 diffuses across , gap / cleft / synaptic cleft
or
reaches second , neurone / cell / membrane , by diffusion ;
3 attaches to , receptors / binding sites of sodium channels ,
on post-synaptic membrane / membrane of second cell ;
Outline the importance of the junctions between neurones in the functioning of the nervous system
ensures movement of , impulse / action potential ,
in one direction (only) ;
2 integration
or
one neurone can ,
connect to / receive impulses from / transmit impulses to ,
many neurones ;
3 allows summation ;
4 idea that filters out , ‘background’ / low level , stimuli
or
ensures that only stimulation that is strong enough
will be passed on;
describe the function of the myelin sheath
structure A / Schwann cell / it , produces myelin ;
(electrical) insulation / insulates ;
prevents movement of ions , into / out of , neurone / axon
or
prevents depolarisation ;
speeds up , conduction / transmission / passage , of ,
impulse / action potential ;
action potentials / local circuits / depolarisation /
only occur at , gaps / nodes (of Ranvier)
A feature of synapses is that they allow transmission in only one direction.
State how this is achieved.
-idea that only the presynaptic neurone
produces / releases / contains ,
acetylcholine / ACh / (neuro)transmitter ;
-only the presynaptic membrane has ,
Ca(2+) / calcium (ion) , channels ;
-idea that only the postsynaptic , membrane / neurone ,
has (ACh) receptors ;
ACh broken down at postsynaptic membrane
Atropine is a similar shape to acetylcholine. The presence of atropine prevents the
initiation of an action potential in the post-synaptic neurone.
Explain how the presence of atropine in the synapse will prevent the initiation of an action
potential
idea that atropine , binds to / occupies / competes for ,
(ACh) receptor on postsynaptic ,
membrane / neurone ;
idea that prevents ACh binding / blocks binding site /
blocks receptor ;
ion gates / ion channels / sodium channels /
protein channels , do not open / remain closed ;
Na+ cannot enter / K+ cannot leave ,
neurone / (nerve) cell ;
no / insufficient , depolarisation / postsynaptic potential /
excitatory postsynaptic potential / epsp /
generator potential ;
(so) does not reach threshold (value / potential
