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

a. myelinated fibres with unmyelinated fibres 

Smaller and myelinated fibres are easier blocked than larger and unmyelinated fibres. 

b. pressure/touch nerves with the dorsal nerves that transmit pain impulses

Activated pain fibres fire faster and the pain sensation can be selectively blocked by LA. Fibres in the middle of a thick bundle is blocked slower than those at the outside of the bundle. 

2. Make a list of the effects of LA on other tissues: 

Cardiac tissue: class 1 anti-arrhythmic drugs (e.g. lidocaine) blocks sodium channels in the heart to shorten the action potential and prolong the refractory period. 

Skeletal muscle tissue:  weak blocking action, no clinical application. 

It can improve a person's state of mind - it influences catecholamine-mediated neurotransmission, inhibiting noradrenalin reuptake  (e.g. cocaine). 

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

The clinical indication it is needed for, like the type of procedure being performed, as well as the duration of action of the drug and how long it is going to be needed for its anaesthetic properties. 

4. Why are LA solutions sometimes saturated with CO2? 

CO2 potentiates the effects of local anaesthetics, increasing the rate of action. 

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

Benzocaine, cocaine and oxybuprocaine.