Chapter 1: activity 7

• a synapse is a functional connection between one neuron and another cell. This other cell could be another neuron or an effector organ (a muscle or gland).
• curare is a chemical substance competes with acetylcholine to block its action since it has similar structure to it.

  curare and acetylcholine are antagonistic substances.
• excitatory synapse:

  the membrane potential of the post-synaptic membrane increases its electropositivity. this moves the membrane potential towards the threshold of depolarization (Irh) and hence, excitatory post-synaptic potential (E.P.S.P) is created. such a response ensures the transmission of the nerve impulse to the post-synaptic neuron and therefore, we call this synapse as excitatory synapse.
• inhibitory synapse:

  the post-synaptic membrane increases its electronegativity. this moves the membrane potential away from the threshold of depolarization (Irh) and hence, inhibitory post-synaptic potential (I.P.S.P) is created. such a response blocks the transmission of the nerve impulse to the post-synaptic neuron and therefore, we call this synapse as inhibitory synapse.
• factors affecting the speed of conduction of a nerve impulse on a nerve fiber:

  1. presence of myelin which speeds up the rate of conduction. (saltatory conduction aka jumping effect)
  2. diameter of the nerve fiber. speed increases with the increase of the diameter.
  3. temperature. speed increases with the increase of temperature.