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

(a) myelinated fibres with unmyelinated fibres:- Smaller myelinated fibres are blocked easier than larger unmyelinated fibres. 

(b) pressure/touch nerves with the dorsal nerves that transmit pain impulses:- Fibres in the middle of a thick nerve bundle is blocked slower than those at the outside of the bundle. 

2.  A list of the effects of LA on other tissues.

Heart: Class 1 anti-arrhythmic drugs block the sodium channels in the heart with the goal of blocking the propagation of an action potential and prolonging the refractory period. 

Skeletal muscles: LA has very weak blocking action, therefore, are not used in clinical application. 

3. What is the basis for the selection of a LA?

Systemic or localized distribution and absorption. 

4. Why are LA solutions sometimes saturated with CO₂?

To lower the pH of the blood during the use of LA. 

5. Which of the LA are typically used for surface anaesthesia?

Benzocaine 

Cocaine 

Oxybupuvacaine