EXCERCISE 3 (Neurophysiology of nerve impulses)

5. Electrical, mechanical, thermal, and chemical stimuli are all capable of generating an action potential.

10. Curare had no effect—an action potential was still generated when the nerve was stimulated at threshold voltage.

11. Curare works by blocking synaptic transmissions so that neural impulses do not travel from neuron to neuron. The detached nerve which we are experimenting with does not have any synapses to be blocked. In a living animal, however, curare will kill, as neural impulses cannot jump synapses to allow the heart to work or the animal to breathe.

Answers to your questions:

5. what kinds of stimuli can elicit an action potential? Electrical, Chemical, Mechanical, and Thermal can elicit an action potential. Another words all of them.

10. Testing the Effects of Curare: Does this generate an action potential? It had no effect.

11. What explains this effect? Curare stops Acetylcholine. It creates a depolarisation block. Disinhibition from blocking interneurons that express nicotinic accetylcholine receptors.

What do you think would be the overall effect of Curare on the organism? Curare affects the synapse rather than nerve propagation. Therefore, it had no effect on the action potential.