elm 11.1

Question 1

what is the most commonly used local anaesthetic?

Answer 1

lidocaine

Question 2

local anaesthesia is what

Answer 2

analgesia of limited part of body. which the patient remains conscious

Question 3

the first local anaesthetic was what

Answer 3

cocaine

Question 4

close to the spinal cord, a spinal nerve divides into ____ and ___ branches

Answer 4

sensory
motor

Question 5

dorsal root ganglion neurones differ from general neurone structure - their cell bodies have a single ___ that splits with one branch going to ____ and other into _____

Answer 5

axon
periphery
spinal cord

Question 6

the peripheral axon terminal of nociceptors is a _______ that possesses reeptors for ________ stimuli (e.g. _________, and mediators such as __ and ____ that are released by damaged tissue)

Answer 6

bare nerve ending
noxious
high or low temp
H+
ATP

Question 7

______ can also respond directly to mechanical stimuli

Answer 7

nociceptors

Question 8

activation of receptors to noxious stimuli generates ______ that are transmitter from the ______ to the _______

Answer 8

action potentials
periphery
spinal cord

Question 9

the generatino of action potential involves the acivation of ___ channels

Answer 9

NA+

Question 10

the termination of action potential involves the inactvtion of ___ channnels and the delayed activation of ___ channels

Answer 10

na+
k+

Question 11

local anaesthetics act by blocking ______ channels
local anaesthetics therefore block _______, and therefore block______

Answer 11

sodium
action potential
nociception

Question 12

Voltage gated sodium channels - open when the membrane is__________

Answer 12

depolarized

Question 13

all voltage gated sodium channels are _______ selective

Answer 13

cation

Question 14

there are ____________ around mouth of voltage gated channels

Answer 14

rings of (negateive) charge

Question 15

a hydration shell is what

Answer 15

ring of water molecules that positive or negative ion attracts

Question 16

amide linked local anaesthetics are broken down in the __________

Answer 16

liver

Question 17

Amine group means that local anaesthetics can become________ - gives them_____ charg

Answer 17

protonated
positive

Question 18

Charged and uncharged forms are in equilibrium and the amount of the protonated form present will depend on the [] of_______ - pH dependent

Answer 18

protons

Question 19

Lower the pH, the _____ local anaesthetics block sodium channels

Answer 19

Lower the pH, the less well local anaesthetics block sodium channels

Question 20

________- form of local anaesthetic binds to sodium channel

Answer 20

Uncharged

Question 21

________ form of local anaesthetic - acting from inside the cell - dugs has to first cross the cell membrane

Answer 21

Charged

Question 22

there are two possibilites examined using a compound called QX314 - has four groups on its nitrogen

Answer 22

permanent positive charge
does not block Na channeles when applied to outside of cells

Question 23

These experiments showed that local anaesthetics like lidocaine - _________ from the inside and that the charged form acts on the channel

Answer 23

block sodium channels

Question 24

Uncharged form is also important - necessary to allow the local anaesthetics to __________ - once inside, local anaesthetics become_________ again and it is the________ form that blocks the channel

Answer 24

pass through membrane
protonated
charged

Question 25

Sodium channels are blocked more strongly when they are in the __________ states - gives rise to phenomenon known as '__________' - channels are more active are blocked more strongly than resting channels

Answer 25

open or inactivated use dependence

Question 26

topical anaesthesia

Answer 26

- Blocking the transmission of signals close to, or at the peripheral nerve terminal - Variation = EMLA (eutectic mixture of local anaesthetics) - Can be used for pain relief from minor conditions - sore throats, mouth ulcers, etc.. Also be used in minor procedures or to reduce pain caused by insertion of hypodermic needle

Question 27

Infiltration anaesthesia

Answer 27

- Injected into tissue around area that needs to be numbed - usually only affects more distal parts of the nerve - terminal branches - Important to avoid injecting into bloodstream - local anaesthetics have serious systemic effects - Possible to add vasoconstrictor such as adrenaline to injected local anaesthetic in order to prolong duration of anaesthesia Used for minor procedures - suturing a wound, or dentistry

Question 28

Nerve block

Answer 28

- Anaesthetic is injected around spinal nerve trunk - everything distal to this point will be numbed - Vasoconstricting drugs - e.g. adrenaline - often added to injected anaesthetic in order to extend duration of anaesthesia - Needle is guided into place with the aid of ultrasound Gives better pain relief than infiltration or topical anaesthesia - allowed for complicated surgeries like knee replacements

Question 29

IV regional anaesthesia

Answer 29

- Pressure cuff to cut off blood supply to limb - local anaesthetic is injected and then wait 20 min Wait time is important to allow anaesthesia to develop and reduce [] of local anaesthetic in blood vessels (avoids system toxicity)

Question 30

spinal anaesthesia

Answer 30

- Local anaesthetic = injected into subarachnoid space just above spinal cord - Results in pain sensation being lost from all regions supplied by nerves that emerge from spinal cord below level of injection - Often used for surgery on lower body but can only be used in bottom part of spinal column - this is where subarachnoid space is large enough to avoid damage to spinal cord when placing the needle - Less versatile than epidural anaesthesia - also tends to produce more motor block than epidural Faster onset and less anaesthetic needed than epidural

Question 31

epidural anaesthesia

Answer 31

- Local anaesthetic = injected into epidural space - just below vertebral column - Performed via a catheter - can be left in place to facilitate further doses being administered - Epidural space is larger volume than subarachnoid space - more anaesthetic is needed and the onset of anaesthesia is slower - Placement of epidural needle is easier than spinal needle and can be performed anywhere along spinal column - Used for analgesia alone - e.g. during childbirth - Or for treatment of chronic pain - Do not tend to affect motor function as much as spinal anaesthesia - advantage in childbirth - Common in procedures where it is desired to keep patient awake during surgery C-section

Question 32

IV lidocaine

Answer 32

- Sometimes used as post-operative pain management strategy - Advantage is that it allows the use of opioids to be reduced Must be carefully monitored to make sure that they are not showing signs of local anaesthetic toxicity

Question 33

3 things of differential blockade

Answer 33

degree of myelination fibre diameter position with the nerve

Question 34

The cells that provide the insulation around A alpha fibres are the: a. myocytes b. Leydig cells c. Schwann cells d. oligodendrocytes

Answer 34

c oligodendrocytes for CNS

Question 35

Select a local anaesthetic with an amide linker group: a. cocaine b. lidocaine c. procaine d. tetracaine

Answer 35

B

Question 36

The pH of inflammed tissue is frequently lowered. This means that local anaesthetics will be: a. less protonated and thus less potent b. less protonated and thus more potent c. more protonated and thus less potent d. more protonated and thus more potent

Answer 36

C

Question 37

Cocaine is no longer used for spinal anaesthesia due to its effects on the CNS. The psychotropic effects of cocaine on the CNS are due to: a. activation of mu-opioid receptors b. block of noradrenaline reuptake c. block of sodium channels on excitatory neurones d. block of sodium channels on inhibitory neurones

Answer 37

B

Question 38

Adrenaline is often added to local anaesthetic injections in order to: a. keep the patient awake b. maintain the patient's heart rate c. restrict blood flow to the area d. increase the diffusion of local anaesthetic into the blood

Answer 38

c

Question 39

Which of the following types of local anaesthesia is most likely to produce block of motor function in a patient? a. Infiltration b. Spinal c. Epidural d. Topical

Answer 39

b

Question 40

Spinal nerve fibres show the following sensitivities to local anaesthetics a. A delta > A alpha > B > C b. B = C > A delta > A alpha c. A delta > C = B > A alpha d. C > B > A delta > A alpha

Answer 40

b

Question 41

A low dose of local anaesthetic entering the brain is likely to cause a. coma b. convulsions c. long-lasting anaesthesia d. pronounced loss of motor function

Answer 41

b