Lecture 1 Flashcards
What is Dysesthesia and paraesthesia?
D-abnormal and unpleasant sensation to normal stimuli
P-altered sensation (pins and needles)
What are a couple good qualities of LA?
short onset good duration doesn't cause permanent damage reversible low systemic toxicity not irritating to tissues
Three parts of the sensory nerves?
peripheral process (dendritic), soma, axon (which has the “axoplasm”)
What makes up the nerve cell membrane?
phospholipid bilayer, proteins, lipids, carbs
70-80 angstroms wide
What is the concentration gradient measurement of neurons?
-70 mV with the sodiums lining the outside of the membrane (Extracellular area).
What is fiber class A delta nerves? myelinated?
yes myelinated, afferent sensory for pain temp and touch
What is fiber class C d gamma c?
not myelinated, afferent sensory for pain temp and touch as well as autonomic fxns
Stimulus of a nerve gets up to what mv? and how long is firing process?
+40 mV (started at -70mV).
1ms
What are the four stages of nerve conduction?
- initial - slow depolarization
- rapid depolarization (after threshold)
- reversal of electrical potential
- repolarization
What is the membrane readily permeable to?
Potassium and chlorine
What are the two gradients involved with neurons?
concentration and electrostatic
What is the firing threshold?
–55 mV
What effect does LA have on the firing threshold?
Raises it, more Na needed to cross membrane
What are the two refactor periods?
Absolute (right after) and relative (in hyper polarized area) refractory
What is salutary conduction?
myelinated cells - signal jumps from gap to gap fast
