• How does the sensitivity for blockade by a LA compare regarding the following types of fibres:

(a) myelinated fibres with unmyelinated fibres; and

Small and myelinated fibers are therefore more easily blocked than large and unmyelinated fibers.

(b) pressure/touch nerves with the dorsal nerves that transmit pain impulses?

The dorsal nerves that conduct impulses are therefore more sensitive to the blockage and are thus also blocked faster than pressure / touch nerves.

• Make a list of the effects of LA on other tissues.

• Hard: The Sodium channels are blocked in the heart, thus shortening the action potential and prolonging the refractory period and thus may result in antiarrhythmic effects, usually caused by Class 1 antiarrhythmic drugs such as Lidocaine.

• Skeletal muscle: A weak blocking effect emerges. There is no clinical application.

• Cocaine: Has an effect on the state of mind, thus increasing the state of mind. May also affect central catecholamine-mediated neurotransmission, thus blocking NA reuptake.

• What is the basis for the selection of a LA?

• It depends on how long the LA will be used.

• What the LA will be used for, its clinical use.

• How long the LA lasts.

• Why are LA solutions sometimes saturated with CO₂?

It potentiates the LA, which therefore means the LA are accelerated.

• Which of the LA are typically used for surface anaesthesia?

• Cocaine

• Benzocaine

• Oxybuprocaine