Nervous System Swyk Response - M5 Flashcards
Outline the roles of synapses in the nervous system
-allows neurones to communicate
-ensures transmission on one direction
-allows convergence
-allows divergence
-filters background/low level stimuli
-prevents fatigue/overstimulatiom
-allows many low level stimuli to be amplified
-inhibitory + stimulatory synapses allow impulse to follow particular path
-permits memory ect
TTX, a neurotoxin is know to reduce the speed of conduction in the purkyne fibres of the heart
Suggest and explain the effect of this on the heart rate
-decreases heart rate
-slows transmission of impulse from AVN to ventricles
-slows ventricular systole
-Contraction begins
-increases time in systole
(squids), Lobsters and sea cucumbers have statocysts
A student conuded from this info that “squids, lobsters, sea cucumbers evolved from a recent common ancestor and are probably classified in the same phylum”
Evaluate extent to which the info about lobsters and sea cucumbers supports the students conclusion
-support is weak
- idea of classification based off phylogeny
-statocysts could have evolved on more than one occasion/be an example of convergent evolution
