Nervous System Swyk Response - M5

Question 1

Outline the roles of synapses in the nervous system

Answer 1

-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

Question 2

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

Answer 2

-decreases heart rate

-slows transmission of impulse from AVN to ventricles
-slows ventricular systole
-Contraction begins
-increases time in systole

Question 3

(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

Answer 3

-support is weak
- idea of classification based off phylogeny
-statocysts could have evolved on more than one occasion/be an example of convergent evolution