ANP 1106 Lecture 16: Nerve Impulse and Synaptic Transmission pt. 2

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1106
• Professor: Jackie Carnegie

Document Summary

Physiology of ns (nerve impulse and synaptic transmission) Graded potentials: stimulus creates short lived localized changes in membrane potential current flow decreases with distance (decremental); they are graded b/c current flow caries with stimulus strength. Stre(cid:374)gth does(cid:374)"t de(cid:272)rease (cid:449)ith dista(cid:374)(cid:272)e (cid:271)/(cid:272) it is (cid:272)o(cid:374)sta(cid:374)tl(cid:455) (cid:271)ei(cid:374)g rege(cid:374)erated do(cid:449)(cid:374) the a(cid:454)o(cid:374)"s le(cid:374)gth. Neuron: dendrites ligand gated channels are activated by neurotransmitters, axons voltage gated channels are activated by depolarization. Synaptic terminals voltage gated calcium channels open to allow neurotransmitters release. Ranvier by graded potential, a new ap is generated at next node of ranvier, etc: myelin in the cns is formed by living oligodendrocytes; in pns its formed from living schwann cells. Blockades of action potentials: blockade of voltage gated sodium channels prevents peripheral nerve conduction = death by paralysis, tetrodotoxin is a neurotoxin found in blue-ringed octopus or pufferfish and some poison dart grogs, 200x more toxic than cyanide.