Wreb La- Ch. 1, Neurophisiology And Pain Control

Front 1

What is local anesthesia?

Back 1

A loss of sensation in a circumscribed area induced by 1)Depression of excitation
2)Inhibition of conduction
(based on Dr.DiMarco's pp)

Front 2

List 6 Methods of inducing LA?

Back 2

1. trauma (hit, or cut the nerve)
2. low temp(ice)
3. anoxia (no oxygen in a nerve)
4. chemical irritants
5. neurolytic agents (alcohol, phenol)
6. Chemical agents (local anesthetic)

Front 3

T/F. Local anesthetics that are only transient and reversible are used in dentistry.

Back 3

True

Front 4

6 Characteristics of useful local anesthetic agents

Back 4

1. Non-irritating
2. no damage or alteration to neural structures
3. low systemic toxicity
4. effective in tissue and on mucous membranes
5. short onset
6. reasonable duration

Front 5

5 more other useful charecteristics of la

Back 5

1. potent w/o high or harmful doses
2. nonallergenic
3. stable in solution; biotransformable on injection
4. sterile or capable of sterilization
5. does not induce unconsciousness

Front 6

T/F. Local anesthetics prevent generation of nerve impulses only.

Back 6

F. LA prevents generation and CONDUCTION of nerve impulses.
(i.e they block the transmission of impulses)

Front 7

T/F. Sensory neuron bodies are located away from the axon and do not participate in impulse transmission. Motor neuron cell bodies are found between axons an dendrites and participate in impulse transmission.

Back 7

T. talking about cell BODY's not axon. Cell body in a motor neuron is located in the middle b/w the axon and dendrites and is involved in impulse transmission. pg.5

Front 8

Dendritic zone of sensory neurons

Back 8

1.The most distal part(from the CNS)
2. An "arborization" of free nerve endings
3. free nerve endings lie in tissue
4. Respond to stimuli by "provoking" impulses

Front 9

Axon

Back 9

Thin, cable-like structure with a 'terminal arborization' that synapses with various nucleii of the CNS.

Composed of specialized cytoplasm, called "axoplaxm" enclosed in long cylindrical sheath called "axolemma"

Front 10

Axolemma

Back 10

~Also called nerve membrane.
1. May be myelinated or non-myelinated. Myelin acts as an electrical insulator to increase the efficiency of nerve conduction
2. Both myelinated and nonmyelinated nerves are surrounded by Schwann cell sheaths

Front 11

Constrictions that occur every 0.5-3mm along the myelinated nerve that are the gaps b/w the Schwann cells are called?

Back 11

Nodes of Ranvier.
~Large nerves tend to have wider gaps and thicker sheaths so that impulses conduct more rapidly

Front 12

T/F. Unmyelinated nerves have no gaps b/w their Schwann cells.

Back 12

True. They have a thin stretched Scwann cell over them. The nerve membrane separates axoplasmic fluid from extracellular fluid by having an electrical resistance 50 times greater than that of the extracellular fluid. This prevents passage of ions down their concentration gradients maintaining the status quo.

Front 13

Sequential depolarization

Back 13

Occurs along the UNMYELINATED nerve membranes by letting the nerve impulse creep or "propagate" down the membrane.

Front 14

Saltatory Conduction

Back 14

Impulses speed along MYELINATED nerves by leaping from node to node.

Front 15

Function of the cell body

Back 15

It and the cytoplasm provide metabolic support for the neuron